Make a cone stop for your slip roller that bolts to the left green angled piece. That guides the cone from spiraling and eliminates the work of “slipping” it in the roller by hand. Also start all cone ends backwards in the roller to eliminate the natural tendency to leave a flat spot. I made many pipes the same way as you demonstrate. I Laser cut now to avoid the tin snips. Keep it up!
Cheers for the tips - I'll look to make a stop before the next phase of construction. Noted about the backwards start - I'll try that too. Cheers for the help 🙂 I've done a few laser cut pipes too... And yes it does make life a bit easier... But I need to get my money's worth out of the new tin snips 😂
Excellent video. I’m about to build pipes for a 73 Brutanza liquid triple snowmobile. Was the first liquid sled ever factory made. Rare. You gave me some nice tips that will make my end result much better.
Hi Scott, I'm pleased you found it helpful. Are you planning on building an expansion chamber? I'm just getting ready to film making the header and flange etc... and the egt bosses. Cheers Dave.
Good stuff! You certainly put a lot of effort into getting each cone dead right and a spot on fit with the next cone, to be honest I doubt that the 'professionals' take as much care as you do!
Cheers Pete - I learnt the good fitment lesson on my first RGV pipes. I spent as long smashing filler rod into the holes made from bad fit-up as it would have taken to spend more time with prep.
Hi Stephen, pleased you found the channel and hope you enjoy the content. My first motorbike was an MT5 so same engine as your MB as I remember? Could be a fun project 😊
My first bike was an Mb5 -loved it but it was way too slow when my mates had fuzzies and Ap50s . As I remember there is a washer welded in the stock exhaust and MOST annoyingly the exhaust port is an astonishing 5mm too low :( The carb is also probably also to small but I loved the bike as a first bike . Next bike was a KH 250 - that was incredible at 17 years old !!!
Cool, what did you make pipes for? I've heard of that method. It sounds quicker than what I use but I have always worried about cutting it up and keeping the ends flat and accounting for the cuts.
made for my lambretta sprint bike in the 1980s if you cut and turn its the same shit worked well got 14 second quarters and 90 mph ..... im sure i could do over 100 now 40 years on ..... make exhaust port wider in the blow down area in a trapisoid shape . the more area you have when the exhaust port first openes the better .... good luck .... i used blairs formula . @@AutoBeta2T
Looking great Dave, love the attention to detail. In a previous comment I mentioned making the front pipe from a single piece of sheet, it's not too difficult to achieve but I only used to do it in the early proof of concept stages, when EVERYTHING is cut and try (I didn't have software) anything to shorten the process is helpful, including converting a 2 cylinder engine to a single lol.... in order to do it you'd probably need to print the segments eye shaped rather than bowtie though. My philosophy then was get it working first then make them pretty. Don't think I'd do it that way now though as I'd guess the software gets it VERY close to ideal. Also when I mentioned the cylinder head cowl a lot of people will say the ram air concept didn't work as Suzuki dropped it for the last 2 models of GT250 however I'm inclined to believe it did work, I've seen GT250 heads with the cowl removed and the fins are about half the length of the later models, I think it was dropped to reduce costs not because of any kind of design failure .
Cheers Roy - I think more time on prep does help ultimately but does take time. I'm in less of a rush now and I'm enjoying having a bit more space to do this with certainly helps
@@AutoBeta2T The software will probably get you to the stage where I would begin to make them with an eye to quality rather than speed of manufacture. Regarding the marking out, I did it the same way, even down to the pritt adhesive lol but I always seemed to have part cans of spray paint lying around, a quick coat once they're stuck down saves all the drawing and highlights the offcuts better. The steel I used was 20 gauge which I got from work ( the pit workshops ) even direct from the supplier there were sometimes sheets with hard patches where maybe the temperature had dropped a little while it was going through th thickness rollers. Final cutting/trimming of blanks I always tried to do at work using a cutter called a Monodex, it's like a 3 prong fork with the center one moving up and down between the outer two, very precise and very low distortion. I was able to use slip rolls at work but anything at home was hand formed on sections of hydraulic ram in a vise as battle scarred as yours lol.
Okay - so .9mm... I've worked with that before and it was good. I got one of the X7 pipes Lasered and it was 0.7mm (22 gauge) and an absolute dick-head to weld. Paint sounds like a good 'hack'! Please to hear the trusty pritt-stick has been going for a while.
I'll have a look at the Monodex. Was it hydraulically operated? It's amazing what you can do with a piece of metal bar! And yes the Record vise has some time in ☺️
Great work. This takes me back almost 50 years when I used to stop behind on the afters shift and cut up 45 gallon drums to make expansion chambers. Oxy acetylene welded with a mumber 1 nozzle turned down as low as it would go. All cut and formed by hand. The expansion chambers were used on 250 singles and made using the trial and error techneque. I would love to have a go hydro forming expansion chambers just for the fun of it.
Cheers Malc ☺️ What was the metal from the drums like to work with? It sounds weird but you can feel the difference between different metal. As the drums would have been formed I wonder if they were fairly soft to work with or had work hardened? I'd love another go on oxy acetylene (last time was BTEC at college in 94...) Hydroforming is interesting. I'm not sure if it's quicker than cones as there's quite some faff with template layout but quicker to make. As for if there's a performance benefit, I'm curious 🧐
I mainly used 20 gauge steel from work but I've been known to cut them from fridges, washing machines, and cookers etc when I couldn't get any lol. And like you it was cut and try, I only had the generic maths formulas from books which do get you into the ball park but obviously aren't optimised
@@AutoBeta2T Back in those days for me it was a matter of using what you could get hold of metal wise. Materials were thicker in those days and did vary from one make of drum to another. We chose the thickest material we could which seemed to be quite stiff, better for welding but harder for forming. Truing was done with a 9" angle grinder fixed to a bench with a new disc which was not too true. By removing the guard you had a good 7" to play with. Welding wise, the material warped with too much heat. I used to love gas welding. At that time I had good eye sight and a steady hand while using my own BOC ultra light welding torch with 1/4" bagging. I found that I could get more into the zone by using the old fashioned twin eye piece BOC goggles, it was like wearing blinkers. One advantage of segments is that you can make one at a time. When working on afters I used to get finished from 11-30 onwards so this gave 1 hours playtime to do my own work. I personally doubt if there's any real performance increase between the two types if made to the same dimensions and build quality. Thanks for your interest.
@@madmaxsdog8040 It seems so easy to get things now the internet is here to stay, There is no shortage of white products littering the fields and street corners
@@madmaxsdog8040 Near home there's a fridge that has been dumped that I've had my eye on... I think most appliances are made from CR1 or 2 sheet steel that has better forming properties and is good for hydroforming. By some fluke I seemed to have found somewhere that does it! I spent a long time some years ago trying to find some CR 1 or 2. coilslitting.co.uk/mild-steel/#:~:text=CR1%20is%20the%20softest%20from,strength%20%26%20quality%20of%20the%20steel.
Nice work! I'm now working on an exhaust for my tuned 117cc maxiscooter (lots of videos about it on my channel) but with all free calculators I've used the best exhaust would look like a straw for some reason. There's no pipes available for tuned Yamaha 4VP10 100cc engine, it's so rare. So I've been testing with performance pipes for Yamaha 70cc scooters because the fitment is almost identical. Top speed went from 80km/h to 120km/h so I believe I have done something right but I'm sure the exhaust is now holding me back. I think all those exhaust calculators I've tested are meant for wide powerband and for scooter you don't really need that. My current pipe is about 2x wider and 30cm longer when comparing to average calculator outcome and still it works the best from all pipes I've tested so far 😃
Hi JoniK, cheers. Yes, the online calculators are not always the best. I've had really good results with Graham Coker's calculator and also with EngMod2T. There are a few more I'd like to try for the AR. What sort of rpm does your maxiscooter peak at? I'd say the pipe I'm currently making could possibly work well on it. Saying that if you've gone.from.80 to 120 km/h then it looks like the pipe you have is in the ballpark 😁
Also if you stress relieve the weld it will release all the distortion. Use a hammer with a solid block on the inside and tap until you see the distortion come out. A ball pein hammer on the inside would do it
so when the pipe expands does that send a pressure wave back towards the exhaust port?? for 2 strokes this is to push the escaping fuel air mix back into the cylinder, is this correct? Also for a 4 stroke is it best to keep the exhaust system the same diameter all the way through, cause I got a 180cc 4 stroke here I'm using the stock downpipe 28mm ID, but the only mid pipes I can find with a 32mm inlet are all 51mm out, its too fucking big for the displacement. We dont want pressure waves going back towards the exhaust port on a 4 stroke IIRC?? So currently I got 28mm header, 32mm mid pipe inlet to 50.8mm OUT, 51mm muffler but inside the diameter is slightly less, with dB killer and the torque is better than the previous owners setup as there was a hugely oversized old scorpion exhaust 51mm NO dB killer. Didnt have much torque until like 7000rpm (im running CVT btw). The one I installed is like half the length half the weight also. I have got plans for the future to change to 32mm ID muffler, can find those online no problem but i would have to find a mid pipe with 28 or 32mm outlet and there aint any i can find. I was thinking of maybe getting a 32mm to 51mm mid pipe and just cutting it back to where it's 32mm?? would this be viable? other option would be same 32 to 51 mid pipe and just add an adapter or bush but i dont think i want that expansion shit in the middle of my exhaust, not for a 4 stroke. Can anyone clarify this please also I dont know welding, i aint fucking around with that
Hi, yes, all correct about the two-stroke pipe theory but there are two waves, a positive and a negative. The negative wave is generated by the first part of the pipe (diffuser) and it sends a negative wave back to the exhaust port to help scavenging around bdc. The rear cone of the pipe sends back a positive wave that then stuffs the spilt out fresh mixture back into the cylinder just before the exhaust port closes. 4 strokes, as I understand, can benefit from the negative wave to help extract gasses from the cylinder and help cylinder filling. Having a stepped pipe acts like a megaphone, which is a bit like the front part of a two stroke exhaust. Note, I'm not that well up 4 stroke theory, so take what I say with a pinch of salt.
Hi and thanks. What cc is your AM6? The dimensions for the pipe are in one of my vids but I can't remember which one. If you drop me an email I'll send you the dimensions Autobeta2t@yahoo.com
Great video. Thanks. I've been following evening classes TIG welding and I think I'm ready for trying out my first 2-stroke expansion exhaust. I have been doing some exercises with pie cuts from a pipe (1mm) and am happy with the result. On the inside of the pipe, there is some (minimal) relief of material on the welds. No issue for 4-stroke. But what about this for 2-stroke?? I can imagine this can have some impact on the flow. Do you file/sand on the inside after welding?
Hi Carrejans, thank you. With the inside of the pipe I do grind the welds to smooth out any weld boogers. Generally it's not too bad if the welder is set correctly. Note: I don't use filler wire on the weld I just fusion weld it; however, on occasion a little filler may be required if there's a gap and this can lead to some blobs inside that need grinding. I also hammer each weld. I'll make sure I cover these points in the part 2 vid. Cheers Dave
True, but possibly the excess material left with the mig would require it being removed that could cause additional time required. I may have a go with the mig to see how it goes. Cheers for watching and have a very merry Christmas ⛄
I'm no authority on expansion chambers by any means so feel free to correct me. I do weld a bit though so here goes. Being such thin material, logic to me dictates , would it be stronger to stagger the seams so they don't all run together. Perhaps try to crush 1 ring by itself and see how the joint holds up. If it is stronger at that point, by the opposing stagger method would it give it more rigidity ?? I would be interested in your thoughts. However As you already run the seam in a straight line have you come to the conclusion it's stronger this way or just for visual evenness . ?
Hi, I generally put them in a line so the angle is correct, if you turn them it shallows the angle of the bend. However, I too have wondered about how it affects the strength. I would have thought it would want to weaken but in reality the rings stay in very good shape. I think it helps as most cone ends meet at an angle making it nearly impossible to bend very easily. So I guess a mixture of aesthetics and keeping the correct bend in the pipe.
Hey i have a question im currently pretty new to designing pipes and im making a pipe for an mhr team 2 77 am6 but whats some good software to do the calculations
There is one here that I haven't used but should give you a good start. www.kiwibiker.co.nz/forums/showthread.php/187285-2-stroke-excel-for-ports-heads-and-pipes
@Cryst_the_sweat yes, I used Mota to print them. There is a free programme (or fairly cheap) that will generate the flat cone templates too. I'll have a look for it.
I dont know how to design a pipe my self so it would even be beter than stock so i dont see the point in trying i will go look else where if people can give their designs
Hi, I used EngMod2T for this one starting with a base design known to work. I also use Graham Cokers' exhaust calculator which works extremely well: m.facebook.com/groups/671081149638729/permalink/3119951054751714/
@kingbarcarsi5661 hi, I don't have any patterns in electronic format. I print them from MOTA straight to paper. I do have the pipe design if you want that?
Gidday Mate, thanks for your video on making an expansion chamber.What was the metal you used please? ive got a bantam that i want to make less ugly.i reckon if i can get it lookig,sounding and goig like i hope it will,i might be able to knock it out to one of these dicks looking for "investment condition" classic bikes. With a backstory like,"it was used by the young Frey Bentos in the welsh reverse hillclimb. good on you mate pat
Hi Pat, I got the metal from here. www.ebay.co.uk/itm/223575488268?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=IcPlBqziTCy&sssrc=2349624&ssuid=rNYQvC4RT7e&var=522320678669&widget_ver=artemis&media=COPY It's the 0.8 mm mild steel sheet. It forms and welds pretty good too. Haha, Frey Bentos 🤣 You've got me hungry now - 🥧 and 🍟's for tea (with gravy) tonight.
Make a cone stop for your slip roller that bolts to the left green angled piece. That guides the cone from spiraling and eliminates the work of “slipping” it in the roller by hand. Also start all cone ends backwards in the roller to eliminate the natural tendency to leave a flat spot. I made many pipes the same way as you demonstrate. I Laser cut now to avoid the tin snips. Keep it up!
Cheers for the tips - I'll look to make a stop before the next phase of construction. Noted about the backwards start - I'll try that too. Cheers for the help 🙂
I've done a few laser cut pipes too... And yes it does make life a bit easier... But I need to get my money's worth out of the new tin snips 😂
@@AutoBeta2T tin snips build character! And it demonstrates simplicity.
Excellent video. I’m about to build pipes for a 73 Brutanza liquid triple snowmobile. Was the first liquid sled ever factory made. Rare. You gave me some nice tips that will make my end result much better.
Hi Christopher - I'm pleased it was of some help. Good luck with the triple pipe build :)
Love your attention to detail- making expansion chambers is lots of fun !
Cheers 😊
Yeah, it's good to get back into it after a few years.
I've always wanted to build my own expansion chamber. Great job and excellent explanation as you progressed. Thank you for your time
Hi Scott, I'm pleased you found it helpful. Are you planning on building an expansion chamber?
I'm just getting ready to film making the header and flange etc... and the egt bosses.
Cheers
Dave.
@@AutoBeta2T yes I have always tinkered with it and now its tome to go for it!!!!!
Sweet - good luck with it 😀
It's a great thing to be able to do!
Good stuff! You certainly put a lot of effort into getting each cone dead right and a spot on fit with the next cone, to be honest I doubt that the 'professionals' take as much care as you do!
Cheers Pete - I learnt the good fitment lesson on my first RGV pipes. I spent as long smashing filler rod into the holes made from bad fit-up as it would have taken to spend more time with prep.
thanks
Only just found your channel, nice work. I've always wanted to do similar to my old Honda mb5
Hi Stephen, pleased you found the channel and hope you enjoy the content. My first motorbike was an MT5 so same engine as your MB as I remember? Could be a fun project 😊
My first bike was an Mb5 -loved it but it was way too slow when my mates had fuzzies and Ap50s . As I remember there is a washer welded in the stock exhaust and MOST annoyingly the exhaust port is an astonishing 5mm too low :( The carb is also probably also to small but I loved the bike as a first bike . Next bike was a KH 250 - that was incredible at 17 years old !!!
Yep - the things they did to keep the power down. The standard AR 50 exhaust port is very low too... And very small.
nice work . i used to make pipes 30 years ago with gas welding , but i was lazy and rolled the header and just cut it and turned it to get my bends .
Cool, what did you make pipes for? I've heard of that method. It sounds quicker than what I use but I have always worried about cutting it up and keeping the ends flat and accounting for the cuts.
made for my lambretta sprint bike in the 1980s if you cut and turn its the same shit worked well got 14 second quarters and 90 mph ..... im sure i could do over 100 now 40 years on ..... make exhaust port wider in the blow down area in a trapisoid shape . the more area you have when the exhaust port first openes the better .... good luck .... i used blairs formula . @@AutoBeta2T
Cool, that sounds fast for a Lambretta! A few people have mentioned about getting the area open quick with the exhaust.
Blair for the exhaust too?
Really good. Got them spot-on for roundness 👍
Cheers Dave. ☺️
Looking great Dave, love the attention to detail. In a previous comment I mentioned making the front pipe from a single piece of sheet, it's not too difficult to achieve but I only used to do it in the early proof of concept stages, when EVERYTHING is cut and try (I didn't have software) anything to shorten the process is helpful, including converting a 2 cylinder engine to a single lol.... in order to do it you'd probably need to print the segments eye shaped rather than bowtie though. My philosophy then was get it working first then make them pretty. Don't think I'd do it that way now though as I'd guess the software gets it VERY close to ideal.
Also when I mentioned the cylinder head cowl a lot of people will say the ram air concept didn't work as Suzuki dropped it for the last 2 models of GT250 however I'm inclined to believe it did work, I've seen GT250 heads with the cowl removed and the fins are about half the length of the later models, I think it was dropped to reduce costs not because of any kind of design failure .
Cheers Roy - I think more time on prep does help ultimately but does take time. I'm in less of a rush now and I'm enjoying having a bit more space to do this with certainly helps
@@AutoBeta2T The software will probably get you to the stage where I would begin to make them with an eye to quality rather than speed of manufacture. Regarding the marking out, I did it the same way, even down to the pritt adhesive lol but I always seemed to have part cans of spray paint lying around, a quick coat once they're stuck down saves all the drawing and highlights the offcuts better. The steel I used was 20 gauge which I got from work ( the pit workshops ) even direct from the supplier there were sometimes sheets with hard patches where maybe the temperature had dropped a little while it was going through th thickness rollers. Final cutting/trimming of blanks I always tried to do at work using a cutter called a Monodex, it's like a 3 prong fork with the center one moving up and down between the outer two, very precise and very low distortion. I was able to use slip rolls at work but anything at home was hand formed on sections of hydraulic ram in a vise as battle scarred as yours lol.
Okay - so .9mm... I've worked with that before and it was good. I got one of the X7 pipes Lasered and it was 0.7mm (22 gauge) and an absolute dick-head to weld. Paint sounds like a good 'hack'!
Please to hear the trusty pritt-stick has been going for a while.
I'll have a look at the Monodex. Was it hydraulically operated?
It's amazing what you can do with a piece of metal bar! And yes the Record vise has some time in ☺️
Very nice and informative video.
Thank you Stijn 😃
Dave, happy new year to you, your family and all the other subscribers. Hope 23 is good to all of you.
Cheers buddy, happy New Year to you and the family too 🎊
I can smell the extra hp 🦾
Nice gloves 😁
Cheers Jim - hopefully 😊
Great work. This takes me back almost 50 years when I used to stop behind on the afters shift and cut up 45 gallon drums to make expansion chambers. Oxy acetylene welded with a mumber 1 nozzle turned down as low as it would go. All cut and formed by hand.
The expansion chambers were used on 250 singles and made using the trial and error techneque.
I would love to have a go hydro forming expansion chambers just for the fun of it.
Cheers Malc ☺️
What was the metal from the drums like to work with? It sounds weird but you can feel the difference between different metal. As the drums would have been formed I wonder if they were fairly soft to work with or had work hardened?
I'd love another go on oxy acetylene (last time was BTEC at college in 94...)
Hydroforming is interesting. I'm not sure if it's quicker than cones as there's quite some faff with template layout but quicker to make. As for if there's a performance benefit, I'm curious 🧐
I mainly used 20 gauge steel from work but I've been known to cut them from fridges, washing machines, and cookers etc when I couldn't get any lol. And like you it was cut and try, I only had the generic maths formulas from books which do get you into the ball park but obviously aren't optimised
@@AutoBeta2T Back in those days for me it was a matter of using what you could get hold of metal wise. Materials were thicker in those days and did vary from one make of drum to another.
We chose the thickest material we could which seemed to be quite stiff, better for welding but harder for forming. Truing was done with a 9" angle grinder fixed to a bench with a new disc which was not too true. By removing the guard you had a good 7" to play with.
Welding wise, the material warped with too much heat. I used to love gas welding. At that time I had good eye sight and a steady hand while using my own BOC ultra light welding torch with 1/4" bagging. I found that I could get more into the zone by using the old fashioned twin eye piece BOC goggles, it was like wearing blinkers.
One advantage of segments is that you can make one at a time. When working on afters I used to get finished from 11-30 onwards so this gave 1 hours playtime to do my own work.
I personally doubt if there's any real performance increase between the two types if made to the same dimensions and build quality.
Thanks for your interest.
@@madmaxsdog8040 It seems so easy to get things now the internet is here to stay, There is no shortage of white products littering the fields and street corners
@@madmaxsdog8040 Near home there's a fridge that has been dumped that I've had my eye on... I think most appliances are made from CR1 or 2 sheet steel that has better forming properties and is good for hydroforming.
By some fluke I seemed to have found somewhere that does it! I spent a long time some years ago trying to find some CR 1 or 2.
coilslitting.co.uk/mild-steel/#:~:text=CR1%20is%20the%20softest%20from,strength%20%26%20quality%20of%20the%20steel.
Nice work! I'm now working on an exhaust for my tuned 117cc maxiscooter (lots of videos about it on my channel) but with all free calculators I've used the best exhaust would look like a straw for some reason. There's no pipes available for tuned Yamaha 4VP10 100cc engine, it's so rare. So I've been testing with performance pipes for Yamaha 70cc scooters because the fitment is almost identical. Top speed went from 80km/h to 120km/h so I believe I have done something right but I'm sure the exhaust is now holding me back. I think all those exhaust calculators I've tested are meant for wide powerband and for scooter you don't really need that. My current pipe is about 2x wider and 30cm longer when comparing to average calculator outcome and still it works the best from all pipes I've tested so far 😃
Hi JoniK, cheers.
Yes, the online calculators are not always the best. I've had really good results with Graham Coker's calculator and also with EngMod2T.
There are a few more I'd like to try for the AR.
What sort of rpm does your maxiscooter peak at? I'd say the pipe I'm currently making could possibly work well on it.
Saying that if you've gone.from.80 to 120 km/h then it looks like the pipe you have is in the ballpark 😁
great job lad keep it going
Cheers Mark - will do.
Dave. That poor vice 🤣 Happy New Year buddy
Happy New year mate 🎊
Yep, the old Record is a trooper!
Also if you stress relieve the weld it will release all the distortion. Use a hammer with a solid block on the inside and tap until you see the distortion come out. A ball pein hammer on the inside would do it
Nice progress. Merry christmas!
Cheers Einar - Merry Christmas and a Happy New Year 🌲🎉
Looks awesome 👍Have a great Xmas mate
Cheers Andy - you too 🌲🎉🎊
so when the pipe expands does that send a pressure wave back towards the exhaust port?? for 2 strokes this is to push the escaping fuel air mix back into the cylinder, is this correct?
Also for a 4 stroke is it best to keep the exhaust system the same diameter all the way through, cause I got a 180cc 4 stroke here I'm using the stock downpipe 28mm ID, but the only mid pipes I can find with a 32mm inlet are all 51mm out, its too fucking big for the displacement.
We dont want pressure waves going back towards the exhaust port on a 4 stroke IIRC??
So currently I got 28mm header, 32mm mid pipe inlet to 50.8mm OUT, 51mm muffler but inside the diameter is slightly less, with dB killer and the torque is better than the previous owners setup as there was a hugely oversized old scorpion exhaust 51mm NO dB killer. Didnt have much torque until like 7000rpm (im running CVT btw).
The one I installed is like half the length half the weight also.
I have got plans for the future to change to 32mm ID muffler, can find those online no problem but i would have to find a mid pipe with 28 or 32mm outlet and there aint any i can find. I was thinking of maybe getting a 32mm to 51mm mid pipe and just cutting it back to where it's 32mm?? would this be viable? other option would be same 32 to 51 mid pipe and just add an adapter or bush but i dont think i want that expansion shit in the middle of my exhaust, not for a 4 stroke. Can anyone clarify this please
also I dont know welding, i aint fucking around with that
Hi, yes, all correct about the two-stroke pipe theory but there are two waves, a positive and a negative. The negative wave is generated by the first part of the pipe (diffuser) and it sends a negative wave back to the exhaust port to help scavenging around bdc. The rear cone of the pipe sends back a positive wave that then stuffs the spilt out fresh mixture back into the cylinder just before the exhaust port closes.
4 strokes, as I understand, can benefit from the negative wave to help extract gasses from the cylinder and help cylinder filling. Having a stepped pipe acts like a megaphone, which is a bit like the front part of a two stroke exhaust. Note, I'm not that well up 4 stroke theory, so take what I say with a pinch of salt.
Superb!!! I am currently rebuilding an am6 engine and need a pipe. Any chance of a link to your section dimensions.
Much appreciated
Hi and thanks.
What cc is your AM6?
The dimensions for the pipe are in one of my vids but I can't remember which one.
If you drop me an email I'll send you the dimensions
Autobeta2t@yahoo.com
Great video. Thanks.
I've been following evening classes TIG welding and I think I'm ready for trying out my first 2-stroke expansion exhaust.
I have been doing some exercises with pie cuts from a pipe (1mm) and am happy with the result. On the inside of the pipe, there is some (minimal) relief of material on the welds. No issue for 4-stroke. But what about this for 2-stroke?? I can imagine this can have some impact on the flow. Do you file/sand on the inside after welding?
Hi Carrejans, thank you.
With the inside of the pipe I do grind the welds to smooth out any weld boogers. Generally it's not too bad if the welder is set correctly. Note: I don't use filler wire on the weld I just fusion weld it; however, on occasion a little filler may be required if there's a gap and this can lead to some blobs inside that need grinding. I also hammer each weld.
I'll make sure I cover these points in the part 2 vid.
Cheers
Dave
If you use a MIG welder you wouldn’t have to mess about with all the clamps. You could hold it with one hand and buzz a quick tack with the other
True, but possibly the excess material left with the mig would require it being removed that could cause additional time required. I may have a go with the mig to see how it goes.
Cheers for watching and have a very merry Christmas ⛄
Hey great video, do you have the file to print out the pieces?
Cheers, I did most of the templates on Mota and that won't export a DFX file. I just prints.it out.
@ is there no way I could print it at home?
@schweiggl1876 I'll have to have a look but I could export as a pdf.
That said I could send you the design and you use the cone program
I'm no authority on expansion chambers by any means so feel free to correct me. I do weld a bit though so here goes. Being such thin material, logic to me dictates , would it be stronger to stagger the seams so they don't all run together. Perhaps try to crush 1 ring by itself and see how the joint holds up. If it is stronger at that point, by the opposing stagger method would it give it more rigidity ?? I would be interested in your thoughts. However As you already run the seam in a straight line have you come to the conclusion it's stronger this way or just for visual evenness . ?
Hi, I generally put them in a line so the angle is correct, if you turn them it shallows the angle of the bend. However, I too have wondered about how it affects the strength. I would have thought it would want to weaken but in reality the rings stay in very good shape. I think it helps as most cone ends meet at an angle making it nearly impossible to bend very easily.
So I guess a mixture of aesthetics and keeping the correct bend in the pipe.
Nice!
Cheers Mark.
How are the RD400 pipes coming along?
@@AutoBeta2T I am moving the shop 100 miles away so the pipes are on hold.
@@SpeedofCheeseRacing ah - I remember seeing on FB. Good luck with the move and have a Happy Christmas 🎄
@@AutoBeta2T You too brother!
Hey i have a question im currently pretty new to designing pipes and im making a pipe for an mhr team 2 77 am6 but whats some good software to do the calculations
Sorry for the late reply. I use Graham Coker's spreadsheet. His site is down, but is on FB last I checked
facebook.com/graham.coker.54
There is one here that I haven't used but should give you a good start.
www.kiwibiker.co.nz/forums/showthread.php/187285-2-stroke-excel-for-ports-heads-and-pipes
can i get the paper templates somewhere i am planing on making an exhaust myself
Hi, I don't have a DXF file for the templates I'm afraid. Only the physical templates.
@@AutoBeta2T did you make them yourself
@Cryst_the_sweat yes, I used Mota to print them. There is a free programme (or fairly cheap) that will generate the flat cone templates too. I'll have a look for it.
www.conelayout.com/
I dont know how to design a pipe my self so it would even be beter than stock so i dont see the point in trying i will go look else where if people can give their designs
What program to calculate you use?
Hi, I used EngMod2T for this one starting with a base design known to work. I also use Graham Cokers' exhaust calculator which works extremely well:
m.facebook.com/groups/671081149638729/permalink/3119951054751714/
what stainless is that sir..
Hi, mild steel sheet. CR4, 0.8mm thick
@@AutoBeta2T thankyou sir..can i use 304 or 201 stainless
@@AutoBeta2T sir send me that pattern pls how to make chamber and cones..
@kingbarcarsi5661 hi, I don't have any patterns in electronic format. I print them from MOTA straight to paper.
I do have the pipe design if you want that?
ok sir..thankyou..
Need all size and paper of cutting size
Hi - are you after the pipe sizes?
Gidday Mate,
thanks for your video on making an expansion chamber.What was the metal you used please? ive got a bantam that i want to make less ugly.i reckon if i can get it lookig,sounding and goig like i hope it will,i might be able to knock it out to one of these dicks looking for "investment condition" classic bikes. With a backstory like,"it was used by the young Frey Bentos in the welsh reverse hillclimb.
good on you mate
pat
Hi Pat, I got the metal from here.
www.ebay.co.uk/itm/223575488268?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=IcPlBqziTCy&sssrc=2349624&ssuid=rNYQvC4RT7e&var=522320678669&widget_ver=artemis&media=COPY
It's the 0.8 mm mild steel sheet. It forms and welds pretty good too.
Haha, Frey Bentos 🤣
You've got me hungry now - 🥧 and 🍟's for tea (with gravy) tonight.
pegalo con iman a los papeles
Cheers - I'll try some magnets.
You actually think that file has any flex in it? Bwahahaha
Hi Phil, I'm not quite sure what you are getting at?
I said I use it because it is rigid.