XR70/CRF70 Top End Rebuild (How to) Pt. 2

[@davoshacks2467]

One of the clearest, thorough and understandably “How To” videos I have seen on KZbin!

[@zchilli0808]

Thank you for helping me rebuild the top end of my daughter’s crf70! Without this video I don’t think I would have been able to. The bike runs fantastic. I think I will do a big bore kit next trip around. I appreciate all of your hard work on this video.

[@cjKnettel]

Just bought a 2006 CRF 70 today and came across you video. Bought it for 700 has a slight knock but guy already purchased all the parts for the rebuild but he didnt want to do it himself and all the quotes were over 2k by mechanics. So now im gonna use this video to do it myself. great video!!

[@turdpike]

Eeesh 2k to fix a lil 70…. Shameful! You’ll have it right as rain for a smoking deal

[@madscotsman3390]

Powerhouse quoted me a worst case scenario of $1440 CAD parts + up to 12 hours labour @ $90/hour. Crazy.

[@wisdomspitter7688]

The seals that you shared part numbers for were helpful. The manual calls that washer for the cylinder to head seal a collar. The exploded diagrams don’t show it very good. I should’ve paid more attention on disassemble. I’ve taken the shit apart 3x to address the POS seal. Runs fine just has a “shitty little oil leak”. Good vid my guy.

[@BrianAuer]

I really appreciate this Video! We’re going to do a rebuild this weekend, and this will be my step-by-step guide 🙏

[@jonmersinger8237]

Doing mine this week. Thanks for the video

[@BrianAuer]

6:16 i’d put something over that crank case hole, just in case that pin flies out and falls in there. Great video by the way thank you!

[@josephbrown5525]

Thanks a lot for the video, very clearly explained!

[@djtindall7236]

Question. But why not ask. I have a 2001 Honda xr70 n we need to do a top end on her. But I guess 2 questions for u 1. Bike starts first kick yet smokes when u railing it hard n has become worse 2. Curiousity question. This bike seems to have the same motor setup as a 110cc pitbike. So we was thinking would the crank accept a 110cc piston n cylinder?? If so would the head not work for us ? Thx for your time awesome video. My son is gunna attempt this job himself ❤️👊💯

[@a.camden4631]

Was this one of the unbranded piston and rings ? Wondering about the cheaper ones on eBay? ... If so how did it hold up

[@turdpike]

No, this was a Pro-X piston kit. Japanese made, same quality as OEM. Unsure of the cheap ones- have never run them before

[@a.camden4631]

@turdpike that's what I just purchased I noticed afterwards in the photo of the video lol, thanks for the help and info

[@themadmedic3804]

I put everything together but meeting a lot of resistance when kickin to start any tips?

[@leetimmins5184]

Where do you dispose of the jet fuel?

[@turdpike]

I butt chug it

[@yahyacelik9062]

@@turdpike where do you located

[@paigetimmins973]

Thanks for posting both parts, I’d hate to be left hanging

[@turdpike]

You’re welcome. My manager tried to tell me that it was a dumb idea. Idk why

[@kraigvanderwyk1153]

Did you perhaps make an error with ring gap spec? I’ve got a brand new cylinder, piston and ring kit and the rings gap at .015” not .05”

[@turdpike]

I pulled those numbers straight from the Honda service manual. Again, I was displaying mm’s, but .015mm sounds tight to me. Have a good double check of yours and compare to what you find online (you can find free manuals) but you will likely need to file the gaps a bit bigger.

[@kraigvanderwyk1153]

@@turdpike my Google search results varied between.009” - .014” with a limit of .020. I put it together at .015”

[@turdpike]

@@kraigvanderwyk1153 you’re talking in inches. I’m talking in MM.

[@pnwnative4465]

Just tried my first top end job, but didn’t see how you remove the valves. I’m still blowing massive amounts of smoke, so I assume the valve stem seals are shot. I didn’t replace them cause I couldn’t find any help on how to. Can you give me a hint?

[@mustardbackpack]

A brake hone works for these tiny cylinders

[@billymiller8936]

Can you use the one old oil o-rings?

[@turdpike]

That’s up to you, they are technically single use only. To do the job properly, you change all the o-rings. That being said, most people would be lying to you if they said they’ve never re-used one

[@billymiller8936]

@@turdpike it makes sense that while your in there to replace them but some cheap rebuild kits don’t come with them

[@turdpike]

@@billymiller8936 Yup. Get what you pay for in those kits! Just use your judgment, if it’s still round looking and not as flat as a pancake, odds are it’ll continue to do it’s job.

[@greentire_media]

The studs that run through the top end doesn’t have enough room to put the 4 nuts on the front any idea why?

[@turdpike]

The cylinder is mated completely flat to the case, and the head mated completely flat to the cylinder?

[@greentire_media]

@@turdpike so the piston housing is matted on the end of the crank case but we just took a look at the piston and it’s not going flush with the housing but we can’t find a way to get it in anymore

[@turdpike]

Not sure what you mean by piston won’t go flush with housing- what was being done to the bike in the first place? A piston change?

[@greentire_media]

@@turdpike big bore kit going from 72cc to 97cc same bike that you’re working on just upgrading the piston and the piston housing

[@turdpike]

@@greentire_media oh I see. Haven’t done a big bore myself, but you should compare the height of the new cylinder vs the old cylinder. Maybe the new one is slightly taller, thus taking up more space on the studs

[@stevedewolf1]

Valve lash adjustment?

[@turdpike]

Is that a question or a statement?

[@stevedewolf1]

@@turdpike sorry, thought the question mark implied that. how bout: did you adjust the valve lash?

[@turdpike]

I did double check the last and it was still in spec- didn’t remove too much material from the seats

[@stevedewolf1]

That’s good. The head I got was totally loose.

[@nolangamezhd8503]

The exhaust was still smoking why’s that?

[@turdpike]

Becaus it was around 3 degrees celsius at the time

[@kylebabcock5756]

torque spec @13:00?

[@nortexnewberry3103]

The cam sprockets won’t fit why is the chain too short I don’t get it

[@turdpike]

If you can’t get it you need to remove the cam chain tensioner. Its mounted on the bottom of the engine, kinda looks like an oil drain bolt

[@Garbagejuicewaterfall]

This man answered your question ! Thank you sir!

[@lobito6998]

Freedom speak ahh 😭