วีดีโอ

muchas gracias por no dejar morir la pasion por los motores 2 tiempos

I have a Honda PXR with various bigger barrels like 65cc Athena,Zeta,Polini but a proper exhaust is hard to come by off shelf so I took a Proma pipe from a Honda MB5 and welded it to fit the pxr and boy that pipe made this thing pull :D .also had it on a Honda MT5 with Malossi.it gave more torque than any of the other off shelf tuning pipes. exhaust design is very critical on 2 stroke ;)

Apologies to tthe DT80 guy who was in the live chat. I was gonna try designing an expansion chamber based on 125LC port maps and timings but there's gonna be far too much guesswork for it to work properly.

whats the 'pipe' called at 14:00

Mike.......some sort of 2t Jedi master

Which correction factors except for ambient temperature and air pressure do you use when running the dyno? It can give big difference comparing tests from different time of the year.

What is MSV?

What about a thinner base gasket ?

the first top with high compression 14/1 is good if you have an expansion chamber the pipe should be 32 mm inside soft bend down or up goes to a strut that is 32 mm inside big side 95 mm inside this joint should be 760 mm counted long way from the piston counted outside expansion chamber middle rear cone should be 95 mm inside 250 mm long cone 27 mm outside tail pipe 220 mm long 18 mm inside end silencer is mounted on it! intake 70 mm long 26 mm carburetor the intake should be narrowed so that it is only 9 mm high 34 mm wide the last 12 mm should be the size of the intake on the cylinder this system makes high speeds in the intake and exhaust chamber close to the speed of sound 1200 meters per second the carburetor will get so cold that ice forms -cold lye makes many horsepower -have pulled off the drive shaft the drive outside many times 50 cc 187 km per hour larger engine volume up to 250 km per hour

what exactly is the red mold stuff?

Infinite thumbs up

For testing could you not space the jug up the amount you want to raise the port then mill the head. to get compression back. A head is easier to replace than the jug.

Does ur lathe not do single point threading?? Only standard threads?? Or you haven’t gotten used to it yet?

tagboard and tin, G@d that brings back memories, before my retirement. PEACE thanks for sharing. Fun Watching. GRD

...water cooled cannot run as high a compression, the head gasket won't take it.Have you seen the 50cc-100cc, drag bikes run mid 9's? (on you tube) I beleive it was right at 100 mph, again 1/4 mile so your goal is very do-able. With proper porting, raise the transfers and exhaust, if you have reeds on intake you can still lower the port. The reeds limit ramming force, but my YZ250 was as quick , and as fast as my 750 Honda, bone stock in a lightened frame, and it, the YZ, was reed block, with slick in custom lay down frame ( I don't care for reeds, but cast my own head to get the plug back to the middle of the chamber). Don't overdo the compression (size of the chamber), but squish is essential to efficiency. Best of luck to you, PEACE GRD

Just found your channel, your videos are really well done and you’re doing all kinds of creative things, very cool. Well done! How’s the bike running these days? How many MPH are you up to? I did something similar as a kid with a minibike, it was a 4 stroke but I slowly got it from 23mph all the way up to 67mph from ages 13 to 18. It was so fun, still have it, hasn’t made noise in about 15 years at least.

Are you running a stroker if not think you need to watch a lad from USA Monzboys he got a tiny scooter CBT clutch doing 99mph it's insane the speed of it

You have got a lot of material to open up that bore

Have you ever had a go at melting Aliminum and pouring it out to make Aliminum rods /bars for rewelding the heads back up save scrapping them there's some very good videos on TH-cam there are Indian/ Pakistani that to it you would save a lot of money 💰 may be worth having a look into

Hello, you asked below "Hi, what do you use to monitor pipe pressure...", here is how to do it th-cam.com/video/gwU-OCX8Vd0/w-d-xo.html You need sensor for pressure (MPX4250 is ok), TDC or ignition pulse to see engine position and oscilloscope.

..I built, rebuilt all my own pipes. ALL OF THEM! PEACE GRD

...yes, and start at about 10" for all sizes, cc. All the boost is expansion chamber, and exhaust port height, (stop widening, instead raise it, square with rounded corners) any exhaust size beyond the head pipe diameter is going in the wrong direction. My 220cc cylinders ended up at 24 mm from cylinder top. I'm 64 and could no longer ride so gave the entire, mod sled to Palace Motorsports in Mitchell, SD. Work with zero squish(really) and use compression instead of worrying about revving. My H2 740cc beat a Paul Gast motor of 1000 cc, and this guy who owned it could hardly contain himself when we raced. His speed 140, mine 130.9. He beat me, but he raved and raved about how my time was quicker ( I always bogged on take-off, as my frame was not up to full throttle laubnches. PEACE GRD I studied Jennings and Cameron for years, but I dissagreed on many points. With 21 mm stingers from Aaen Performance my sled would barely pull itself, it's that critical, ( to the porting) PEACE GRD

The head on the right looks like a Yamaha TZ250 RR head

One question and one comment Dave. What is the header I.D. on your AR? I'd guess it's the same as an RD/DT 80 or very similar. See if I can come up with a pipe design for the guy who wanted one. I used to melt candles to mould combustion chamber shapes, I'd guess its a lot more rigid than the silicon rubber you're using so prolly easier to match when machining, wouldn't work on transfer ducts and that kinda thing tho, you'd have to melt it back out lol. Edit, I have port maps for 125LCs and I don't think the 80 will be much different, maybe slightly more radical but it'll only be a couple of degrees, close enough to "make" a street pipe with a decent power boost, might be a couple of hundred rpm away from the proper tuned length but it'll still work Another edit. It might be worth actually riding the bike with the different heads, dynos are great but only tell part of the story and head design affects part throttle ( which you prolly won't be doing much ) as well as the willingness to over rev and how hard the engine actually pulls when you change up and the rpm drops. Yet another edit. I found a very sheltered stretch of road and painted markers along the side for "seat of the pants" tuning and sometimes found that the engine/pipe which may be one or two bhp down on the "best" dyno configuration was better in real life cos it.pulled harder after gear chamges. Might be worth trying Regards Roy. And yet another edit. When I mentioned trading peak power for "pull" I'm talking about 45--65 bhp RD race engines, 250/350/400 and various overbores where the trade off is prolly worth while but on a 90cc? Dunno, it seemed to me at the time the trade off works better on larger capacity but who knows for sure until they try it. Best bet is ask Aprillia, or someone like Kevin Cameron, Jan Thiel etc, and Luc Foekema, all of them are on FB or TH-cam. Another other extra edit. Ron Haslam taught me a lot about porting in the mid 70s when he was on the Pharoah Yamahas, he'd been to Kennys training sessions and saw what Kel was doing to the TZ engines and I just started chatting with him at Croft when the "Paddock" was literally a field with tents and about a million 10 mil spanners lost in the grass 😂❤ but the main things he mentioned was gaining blowdown without extra timing ie make the exhaust port a "flat bottomed vee" and re directing the transfers a little more to the rear of the cyl at different angles to standard, the main ports needed a slightly more rear flow to match Kels exhaust port shape, Ron knew I wasn't a competitor so spoke freely about it, but anyone who has met Ron will tell you in spite of the fame he's one of the most down to earth guys you'll ever talk to about anything. He knew f☆☆☆ all about expansion chambers at the time tho lol😅, all he knew was Stuart Toomey, Kevin Cameron, Erv Kanemoto and Dave Swarbrick all made better ones than the standard TZ750. I've got no idea how many RD250 cyls I wrecked trying to get that somewhere near right but at the time the 125 law had just been introduced and RD250 engines could be bought for about 20 or 30 quid from a breaker, or even whole bikes for 50 sometimes if they had "cosmetic damage" ie almost everything apart from the engine and frame lol

Too bad it broked so quick. I think resleeve it first

I recommend putting spark plugs made in the USSR a17b

X7 is a Nice Bike👍🏻

I would get it resleeved, PJME do them. They are weak across that part. It would weld but chances are other side is going as well

Contact Alex on the two stroke stuffing you tube channel, he’s working one 2 stroke concept stuff , but more importantly he’s got a cnc which seems to need constant love and attention 😂 which he is able to give. Keep up the good work

Can i tru tonhelp you from Spain?

PJ engineering @ Wolverhampton will put you a new liner in , they do an excellent job

Get a blank sleeve from L.A Sleeve or a local sleeve company. Cut to the bore you want and cut the ports out!

That's 1 of the old school good kits

Start monitoring pipe pressure and set your finish timing to get your pipe pressure. Very cool setup you have

I reckon you could have that laser welded for sensible money. I've used EMP Tooling in Havant near Portsmouth a few times over the years for laser welding.

Thank you for Research and information. I watch this video 3 days ago , it help me to find out why "Mechanical Wave" too strong when i install "High flow Silencer" This Video help me alot to learn How in control "Mechanical Wave" inside Exhaust port and Exhaust chamber , too strong "Mechanical Wave" make Air and spray-fuel Separate (Air/fuel burn slower at high RPM + small black dust on spark plug) , too weak "Mechanical Wave" losing power Thank you very much.

The real A. Graham bell in 2024

Your looking for disaster with no chamfer on the port you will snag a ring.

More octane needed ? More timing ?

Port flow is not all there is... you have to have a lot of things right, EX. A good tuned exhaust expansion chamber, max compression, tuned intake, high flowing carb.an exellent high quality ignition, good cooling, etc.Study how you can improve every component on the engine and bike and you will be a winner, Now i know 2 strokes pretty well, did a lot of winning with them, they called me ,Fast Freddie, because of it .

Great guy, he ported my 75 RD250, and made a set of pipes to match we had 46 at the rear wheel on the dyno, I still use the bike absolute transformation, great video thanks 👍

I could have told you these results and saved you time. lol.. Yes, reducing compression reduces power. That's a given

I don't understand why lowering compression ration would help you unless you are trying to avoid detonation (ala turbo). NA Race engines increase the compression riding the fine line of detonation.

16+hp .. you should be around the 30hp mark with all yhe work and effort. Whats home wrong 😮

Can I use modeling clay in this way?

B10EV plugs that should have read.

I remember using specs from a motorcycle magazine to tune one of my 350LCs years ago. I still remember some of the requirements: raise exhaust ports 1mm, squish clearance 0.9mm, set ignition timing to 1.9mm BTDC, and run NGK B9EV plugs. Standard pipes, air box but no filter. I also ran slightly larger 28mm choke carbs from an RD250/400. I recall it being a successful tune, boosting power but maintaining reliability.

I had an AE80 back in the day. Great fun!

This is probably going to sound odd but I’m watching because of my love for ported chainsaws and to see if there’s anything that can I apply for more power.?