Page 1 of 1

Rebuild kit for a CRF80

Posted: Fri Jun 28, 2019 10:00 am
by 1_black_dyna
Bought a CRF80 with the understanding all it needed was a compensator cover and a rear tire. The top end is totally screwed on this bike. Cam chest seems hallowed out maybe from previous owner running too hot and/or no oil. Cam is very loose as well, anyone have suggestions on a rebuild kit or what would be best approach? Got the bike cheap but now I’ve replaced so much stuff I’m worried I couldn’t even get my money back as a parts bike

Re: Rebuild kit for a CRF80

Posted: Fri Jun 28, 2019 12:04 pm
by JimDirt
Welcome to the site !! \:D/

I guess it depends on what your goals are for the bike ..... if its just for the kids to putt around , then you could save some money buy buying used parts on EBay , etc. , (head, cam etc.) , if it was lack of oiling causing the issue , then a whole rebuild would be in order , needing crank/rod , piston ,bearings , gaskets and whatever needed to be done (parts or machining wise) for the head ,or even locating (EBay again) a complete running used engine , so the cost can vary , and the depth of the repair/rebuild can vary greatly ...... Again , the goal you have for the bike (along with your budget) will determine what you need to pursue , as there are many variables here ....

So ...... Determine your budget and goals , then decide how far into this you personally want to go (doing the work yourself , farming it out to a dealer or machine or bike shop) , and what you expect out of the bike (trail riding or putting around the yard , etc.) , that will get you started , but there are so many variables , that there is no "do this" answer , without more info

You did not mention the year and that will play a huge factor in if its worth the cost versus cutting your losses and finding something else ..... again . many factors at stake here ......

Re: Rebuild kit for a CRF80

Posted: Fri Jun 28, 2019 1:52 pm
by 1_black_dyna
Sorry Jim, it’s a 2005 model. And yes it was bought cheap to just let the kids scoot around the house and field behind us. It will turn over, has compression and spark. But like I described on the head the valves are waaaay off. Seems like it’s jumped timing and the cam etc is shot. I’ve heard the 100 motors will bolt up as well, so I guess just look to replace motor all together? It wasn’t bought with the intention of being anything special. I just want to get it running...

Re: Rebuild kit for a CRF80

Posted: Fri Jun 28, 2019 4:10 pm
by JimDirt
Yea , being that old , if you want to do the most for the least , then I would just go the used route (either head or complete engine) , and call it good ...

Those engines are fairly bulletproof , so if you just get the "needed" parts it should still last a long while after that .... The kids will outgrow it before it wears out completely ............

Re: Rebuild kit for a CRF80

Posted: Sat Jun 29, 2019 5:14 am
by 124
You can get a head, cam, valves, and new cam cover for $350-ish. I'd be surprised if it needed all of those new parts but even if it did, the bike is worth it. You say you picked it up cheap, guess you got what you paid for! :shock: Just kidding...

Seriously tho, if it has compression, then the cylinder is likely ok. Even with oil starved head damage, $300 shouldn't put you out of the ballpark for value. Decent running/looking CRF80's of that vintage go for $800-1200 around here. Not sure where your market it but regardless, kids will enjoy it.

I'd open it up, but out the calipers, and see what is going on inside of there.