As some of you may have seen in my introduction post, almost a year ago I had a major top end failure on my 88 Fourtrax 300… After talking to a local guy that knows a lot about the older Honda stuff, mainly since he’s a 3 wheeler nut, I think it was a timing chain tensioner issue… He claims he’s seen the tensioners release tension every now and then when they get hot as they get older.. How likely that is, I don’t know, but I do know somehow my timing chain managed to skip a few teeth on the gears, making the valve timing be wayyy off when I was running it at high RPM’s in 5th gear…(little late night country cruise with a buddy and we were screwing around trying to hurry up since it was about 25 degrees out) anyways, the piston smacked the intake valve and broke it along with bending the exhaust valve, and knocking a nice big hole in the piston.. It also broke the intake rocker arm off. Up until that point, I had done just enough to keep the ol Honda going since it was a cheap four wheeler for me, and I was still in college.. I figure I’ll document my rebuild on here, that way it’s easier for me to ask for help when I need it, and to kind of get my feet wet on this forum finally.. I’ve put a little list together of what all I’m going to need, but I’m debating how to go about it all, so I figure I’ll ask you guys for some advice..

Here’s my list as far as I have put it together:
1. Piston kit- I found the Namura kit on eBay, and was wanting some feedback if anyone has used this kit before? I’ve heard good things about Namura before, but want to be sure
2. Both valves, probably just going back with OEM ones, found a decent deal..
3. Intake valve guide
4. Top end gasket kit, I’ve went with the Tusk kit before, and really liked it, so I’m probably going to go back with it..
5. Camshaft- mine shows excessive wear(one of the things I kind of chose to overlook before) I’ve read that the early 300’s have a different cam, how much power loss would I notice if I went with a later style one? Or should I go with one from a big red? (Which I’m guessing is the old 250’s)
6. Timing chain guides and chain- mine are worn really weird and need replaced, and obviously I might as well go ahead and replace the timing chain…
7. Rocker arm- probably just going with OEM here as well..
8. Jug- mine was kind of messed up when I got the 300, as the bottom of the timing chain tunnel where the two bolts goes through was broken away from the jug, but I had that tig welded back together.. The bore was beat up just a little bit from the valve beating around inside so I’m either going to see about getting it machined by a local machinist that does a good job, or buy a used one in decent shape(which do you guys think I should do?)
9. Head- I’m not sure if I’m going to get a replacement one, or try mine.. It was beat up a little from the valve, but I took and essentially polished the combustion chamber with a die grinder which I know will lower my compression ratio some, but I don’t think it’ll be bad(I’m a mechanic which has come in very handy so far on this) I can post pictures and see what you guys think..

I’m completely open to suggestions on this entire thing, which is partially why I have everything listed out like it is.. If anyone has suggestions on a brand or type of part that I should get for it, just say so.. Haha I really want to do this thing one last time for at least a good long while and do it right, but I don’t want to throw an entire bank at it.. I’d like to keep it at a feasible budget.. Or any suggestions as to where to get parts other than eBay, since some things are kinda limited to find on there.. Oh and with the jug and piston deal, if I go with a replacement jug, should I still just go ahead and use this as a chance to go to a bigger bore? I noticed piston kits didn’t vary much in price due to bore size..

With this four wheeler, I mainly use it to ride around the country roads and zip around my farm, with the occasional light trail riding in a very remote wooded area/creek.. I have 25 or 26 inch tall tires on the back, and hardly ever have a second rider, usually just a cooler on the back.. I know with the taller tires on the back I’ve had it running continuously about 55-60 Mph before(riding next to a 420ES of a buddy…) thanks in advance guys.. I’ll get some pics up of everything soon, since I know that you all are picture lovers… lol