Thanks for making this. I just got a z50 with the same motor and a 88cc kit. I had to tear it down as the head gasket wasn't sealing up and it had a few oil leaks. Never worked on one of these so this was a huge help. Thanks!
At 1:05 you install the oil return passage o-ring onto the cylinder without the steel sleeve/collar, I had to do the same thing. In video 2 of 4 of this series (at 6:32), you can see the collar I'm talking about. (Its part #4, 90603-GB0-911 (Collar 14.8mm) on www.partzilla.com/parts/search/Honda/Motorcycle/2007/CRF50F+A/CYLINDER/parts.html). I couldn't find the original o-ring I removed, but the ones in the kit wouldn't fit around the collar anyway. Just checking to see if you think it's OK without the collar, because I had to do it the same way. Great video's BTW, I've watched ones for bikes I don't even own.
An excellent video. Any engine builder/modifier should know the relationship between the crankshaft and the camshaft. The camshaft spins at at EXACTLY one half the speed of the crankshaft. If any engine builder does not understand this basic design, he should not build an engine. I've actually encountered an engine builder who did not know this basic principle. He refused my business. Thank my lucky stars that I knew what questions to ask. He didn't appreciate that I question his expertise.
Matthew, I must say...this is the best mechanic video I've seen in a long time! Great job! I do have a few questions though. Would this engine be the same as a Passport 70 and if I purchase an 88 kit, do I need the larger carburetor? Also, any estimation on power difference between the original 72cc and 88cc? Thanks again for the great video!
Anytime i remove a cylinder head that i plan on reinstalling i remove the cam, lifters, and valves. Inspect the valves for cupping. If the valves look good, lap them with course lapping compound, then fine. After cleaning the carbon from the head, install valves using NEW valve seals with some assembly lube on valve stems. Not to forget to clean cam lifter parts and assembly lube cam and lifter assembly. Then test valves to ensure they are sealing by pouring gas in head with a spark plug installed and wait for half hr. with head upside down. Unless the head is practically new i suppose. Why wouldn't you? Serious question.
I may be missing something, but wouldn't it take some possible error out of the process by taking a paint pen and making a mark across the cam sprocket and timing chain before removal?
Great video, very informative, but why isn't there any, "run videos" out there showing the performance of the new engine. I think that would be an obvious expectation to see the difference in performance.
At 10:00, maybe those 2 screws could be exchanged for bolts. I am installing a 88cc kit on a 1970 CT70 engine and it has bolts, not screws. So much easier.....then I look closer and your screws have flats too. Is there a reason you are not using a wrench on those instead of a screwdriver? Excellent video, thanks.
My head has oil all over the "gears" inside. Also my piston has carbon on the top of it. How can I clean these? Can I dunk the head in water with the valves still in the head? Thanks
hey man my CRF 50 has the big kid in it to but when I got it I don't know what it is but when I hold my hand over the filter it runs right but when I take my hand off of it isn't back firing starts raining like s***
I'm putting an 88cc kit on my crf50. I got the kit from 50 caliber Racing. For some reason when I assemble the head and cylinder back together the cam sprocket is about 1/4 inch from where it needs to be on the cam. I didn't change the Chain or the sprocket. The only thing I can think of is the cylinder is slightly taller or the gaskets are thicker. Unfortunately, like an idiot, i trashed the gaskets and sold the cylinder before I reinstalled the new Parts. Any insight as to what I may be doing wrong? I checked to make sure the Chain was on correctly inside the crankcase and even spun the crank over multiple times. No kinks in the Chain or anything!
Hey, i dont know much but i have a problem with the original engine.It sounds like screaming silently and it comes from the head i dont know what it is and how to fix it, can you understand the problem?(bad english)
does anyone know if you're going from a CRF 52 and 88 Bore Kit if you have to change the head as well as a cylinder? Where the top of the piston hits the head there is a black resin like Mark that is perfectly the same size as my old cylinder. but when I put my new cylinder on my old head the new hole is now bigger than that black hole is that okay?
I got a problem, i have chinese 50cc minibike and i got a 72cc automatic motor which cluch is toastand i had topend of the 72cc put on the 50cc but after it all is together if i have the head tightened the piston would not move after it is at almost the top dead center and if i loosen the head it moves the heqd a litle, was gona try to put a second gasketbetween the head and sylinder, would that be ok/work?
Great Videos. U should stripped it all the way down and powder coated the Frame, Swing Arm and engine covers, but I am sure you ride the shit out of it instead of more of a Show Bike. Great Job !!
Thanks for making this. I just got a z50 with the same motor and a 88cc kit. I had to tear it down as the head gasket wasn't sealing up and it had a few oil leaks. Never worked on one of these so this was a huge help. Thanks!
At 1:05 you install the oil return passage o-ring onto the cylinder without the steel sleeve/collar, I had to do the same thing. In video 2 of 4 of this series (at 6:32), you can see the collar I'm talking about.
(Its part #4, 90603-GB0-911 (Collar 14.8mm) on www.partzilla.com/parts/search/Honda/Motorcycle/2007/CRF50F+A/CYLINDER/parts.html).
I couldn't find the original o-ring I removed, but the ones in the kit wouldn't fit around the collar anyway. Just checking to see if you think it's OK without the collar, because I had to do it the same way.
Great video's BTW, I've watched ones for bikes I don't even own.
Excellent video man ! congrats ! one question... what is the parts do I need to buy in order to install your full suspentions? thanks in advanced...
An excellent video. Any engine builder/modifier should know the relationship between the crankshaft and the camshaft. The camshaft spins at at EXACTLY one half the speed of the crankshaft. If any engine builder does not understand this basic design, he should not build an engine. I've actually encountered an engine builder who did not know this basic principle. He refused my business. Thank my lucky stars that I knew what questions to ask. He didn't appreciate that I question his expertise.
Matthew, I must say...this is the best mechanic video I've seen in a long time! Great job! I do have a few questions though. Would this engine be the same as a Passport 70 and if I purchase an 88 kit, do I need the larger carburetor? Also, any estimation on power difference between the original 72cc and 88cc? Thanks again for the great video!
You can do a 88 kit with stock carb but you may need to go a size bigger on the main jet and pilot jet
Dang! Setting the timing with the head off was a boss move. Even as an initial eyeball step, that's still really helpful!
I'm sorry, I did not write that info down. The owner recently sold the bike. It did need a richer pilot jet though.
Anytime i remove a cylinder head that i plan on reinstalling i remove the cam, lifters, and valves. Inspect the valves for cupping. If the valves look good, lap them with course lapping compound, then fine. After cleaning the carbon from the head, install valves using NEW valve seals with some assembly lube on valve stems. Not to forget to clean cam lifter parts and assembly lube cam and lifter assembly. Then test valves to ensure they are sealing by pouring gas in head with a spark plug installed and wait for half hr. with head upside down. Unless the head is practically new i suppose. Why wouldn't you? Serious question.
Hold one end of a screwdriver to your ear and the other to problematic areas. Locate the problem and tear it down.
Sounds like it is running lean?
Thanks for the 4 part videos. It helped me a lot.
No problem!
I may be missing something, but wouldn't it take some possible error out of the process by taking a paint pen and making a mark across the cam sprocket and timing chain before removal?
Yes, Chris, I suppose you can make that mark and have it assemble quicker that way.
Great video, very informative, but why isn't there any, "run videos" out there showing the performance of the new engine. I think that would be an obvious expectation to see the difference in performance.
I don't think I had a go pro at the time.
Sure sounds & starts nicely! I hope my CT70 does the same.
Thumbs up man..Very well made, informative video. Think I may get a big bore kit for my Xr50 after watching this.
Thanks
At 10:00, maybe those 2 screws could be exchanged for bolts. I am installing a 88cc kit on a 1970 CT70 engine and it has bolts, not screws. So much easier.....then I look closer and your screws have flats too. Is there a reason you are not using a wrench on those instead of a screwdriver?
Excellent video, thanks.
IIRC I could not get a box wrench closed end over the hex. So I used a P3 instead.
My head has oil all over the "gears" inside. Also my piston has carbon on the top of it. How can I clean these? Can I dunk the head in water with the valves still in the head? Thanks
great videos man, very well done. I feel like i owe you a 12 pack
Thanks Dave!
Your welcome!
Hello how can i know that the oil pump is working properly how can i check this?
hey man my CRF 50 has the big kid in it to but when I got it I don't know what it is but when I hold my hand over the filter it runs right but when I take my hand off of it isn't back firing
starts raining like s***
No problem. Glad it helped :)
Can you rephrase your question?
No problem!
Great videos! Very well done! Thanks for putting this out there.👍🙏🇺🇸
I have two leftover small black orings?
I'm putting an 88cc kit on my crf50. I got the kit from 50 caliber Racing. For some reason when I assemble the head and cylinder back together the cam sprocket is about 1/4 inch from where it needs to be on the cam. I didn't change the Chain or the sprocket. The only thing I can think of is the cylinder is slightly taller or the gaskets are thicker. Unfortunately, like an idiot, i trashed the gaskets and sold the cylinder before I reinstalled the new Parts. Any insight as to what I may be doing wrong? I checked to make sure the Chain was on correctly inside the crankcase and even spun the crank over multiple times. No kinks in the Chain or anything!
Could you used the stock head?
Very nice presentation for sure. Could you have put a better cam in without changing anything else? Thanks
Cam only upgrade would not create as much power as the 88cc kit.
Thank you!
Great Work - very helpful - thank you for sharing your knowledge.
Used cylinder?
is that the standard cylinder head off the 50cc you've paired up with the 88cc bore kit?
Yes.
cheers pal I have the same engine in my cub 50 that I'm turning into a streetcub
Cool project.
Wat too diode u use to take first wheel u put on
What oil do you use?
Hey, i dont know much but i have a problem with the original engine.It sounds like screaming silently and it comes from the head i dont know what it is and how to fix it, can you understand the problem?(bad english)
What a great vid, thanks for taking the time to post!
Did you loosen the rocker arms or does the cam spin freely when you were installing the cam gear
Thanks
Install was done at TDC, so rockers were off cam lobes. Cam will not spin.
Go for it!
Honda GN4 10w-40
Question why use the low compression piston with this kit? Why not dome?
These are the parts I had on hand at the time.
MatthewMCRepair I hear yah there
Is here any thing else you need to do if it is a stock motor with no kit at all.
Can you restate the question?
What is the cylinder diameter?
Hey what sise carburetor do you recommend for a 88cc big bore kit
Contact Tboltusa, they can help you out.
Micuni 70mm
does anyone know if you're going from a CRF 52 and 88 Bore Kit if you have to change the head as well as a cylinder? Where the top of the piston hits the head there is a black resin like Mark that is perfectly the same size as my old cylinder. but when I put my new cylinder on my old head the new hole is now bigger than that black hole is that okay?
IF I GOT AN 88 BIG BORE KIT DO I NEED A NEW CARB FOR THE 88 BIG BIRE OR CAN I USE MY 50 CARB IS THERE AN 88 CARB?
It will work with stock carb. You might have to mess with the jetting though.
I have a 70cc baja dirt bike four stroke is there any bore kits for it?
Contact these guys: tboltusa.com/
Can i use the stock 50cc head to a 72cc uppgrade (so I only buy the Cylinder kit)
+Sandizxx I think you can. Contact tboltusa, they should be able to help you.
What forks do you have on there" they look like kx 60 forks if they are what have done to them to make them work.
I'm sorry I don't know. It's not my bike and the owner sold it.
What kind of oil did you put in there
Probably Honda 10w40
I got a problem, i have chinese 50cc minibike and i got a 72cc automatic motor which cluch is toastand i had topend of the 72cc put on the 50cc but after it all is together if i have the head tightened the piston would not move after it is at almost the top dead center and if i loosen the head it moves the heqd a litle, was gona try to put a second gasketbetween the head and sylinder, would that be ok/work?
I have no experience with the chinese stuff....sorry.
thank you very much this helped me a lot :)
Great vid! 👌 really helpful
How tall is the cylinder. I saay this because im a 69mm cylinder.
Not sure sorry
You think a 125cc heah can fit on a 110cc motor
I have no idea.
You forgot to add "no douche bag" music in the background :)
Your welcome.
oh man just saw the beer buy link ha, did it.
how many torgue you use on the head nuts?
I forgot. Grab the service manual from my site and look it up: www.howtomotorcyclerepair.com/honda-z50a-z50r-service-manual/
MatthewMCRepair man another thing..i tried to do the same today but the head lose oil and smoke what gone wrong?
Leaking oil and smoking out exhaust? Did you put in all the correct orings and gaskets?
MatthewMCRepair oil and and snoke came out between head and cylinder nowhere else i open it again i replace everything and the same thing happens
Email me some pics here: www.howtomotorcyclerepair.com/contact/
Thanks
Thanks for the info! :)
i like your vids , cool
Ok thanks
Great Videos. U should stripped it all the way down and powder coated the Frame, Swing Arm and engine covers, but I am sure you ride the shit out of it instead of more of a Show Bike. Great Job !!
+Silk Boxing Thanks, and FYI this is not my bike.
crf50*
thx for the videos!!! Nice work! Ready to through mine on :-) 2006 CRF50
Cool. I just picked up an 89':
th-cam.com/video/lyC-iuOE4sg/w-d-xo.html
It’s not really a big bore because your using the same sized cylinder and head lmao