Honda TRX ATV Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hey guys, I have a 2002 400ex. I bought it and it needed valves and a new piston with rings. I bought a spare motor and swapped the cylinder and piston onto the motor that is in my bike. The head had a bent valve, I took a good valve from my other head and put it right in there, I didn't get it lapped or anything. I put everything back togather and tried starting, it fired up right away for about 1.5 - 2 seconds, at this point I didn't have the gas tank on so I figured it had no gas, so I put the gas tank back on, but she would not start up again! I don't know what to do. I'm pretty sure the timing is set dead on. Could you guys give me some suggestions please? Thanks
 

·
Super Moderator
Joined
·
4,400 Posts
Engines are like cakes - put in the right stuff in the right amounts and you get an acceptable result.

Start with the simple stuff - you need spark, spark at the right time, compression, fuel and air in the right amounts and it's going to run.

If you have spark then check the compression - with a guage and the throttle held wide open - compression should be about 120psi

Let me know what you find out and we'll go on to the next step
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 ·
L

hey, thanks for the reply, i appreciate it. my stepdad was convinced that it was a timing issue however, i was convinced the timing was dead on. sure enough, the timing was ever so slightly off. i got it started. but i have another problem. when re installing the valve cover there were 3 or 4 bolts that just wouldnt tighten down any, they would grab the threads and then as soon as i start cranking down on them they stripped. i dont think they are completely stripped though. my valve cover has a pretty decent oil leak now. any ideas on what i could do to get it tightened down?

also, i have an issue with my clutch. if i pull it in all the way, and then try and push the bike when its in gear it will still turn over the motor, so obviously the clutch is not working right. i have another clutch that i could just drop into it. but do you have any idea what may be causing it to not work properly? thanks again buddy, your help is appreciated!!
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #4 ·
:)

hey, thanks for the reply, i appreciate it. my stepdad was convinced that it was a timing issue however, i was convinced the timing was dead on. sure enough, the timing was ever so slightly off. i got it started. but i have another problem. when re installing the valve cover there were 3 or 4 bolts that just wouldnt tighten down any, they would grab the threads and then as soon as i start cranking down on them they stripped. i dont think they are completely stripped though. my valve cover has a pretty decent oil leak now. any ideas on what i could do to get it tightened down?

also, i have an issue with my clutch. if i pull it in all the way, and then try and push the bike when its in gear it will still turn over the motor, so obviously the clutch is not working right. i have another clutch that i could just drop into it. but do you have any idea what may be causing it to not work properly? thanks again buddy, your help is appreciated!!
 

·
Super Moderator
Joined
·
4,400 Posts
First - the stripped bolts - the best fix is to have the threads replaced with "Heli-coil" thread repair or something similar. "Re-coil" is another option. But, "on the cheap" would be to get bolts about 5mm (1/4 inch) longer. There is usually threads deeper into the hole than the length of the original bolt. A longer bolt will "catch" the unused threads. Use care when tightening the longer bolt. If it bottoms out in the hole and you continue to tighten, it will strip out the remainder of the threads. You might have to use a washer or two to get the bolt to put pressure on the head cover without bottoming in the hole. Another thing - silicone seal is a no-no. If the head cover was sealed with silicone seal, excess silicone may be pushed into the bolt holes causing the bolts to push against the rubber material before they get tight against the head cover and will cause the bolts to strip the threads before they ever put pressure against the cover. If you suspect silicone in the bolt holes, use a small pick to remove the stuff from the holes to prevent more problems. If you didn't, you should clean the gasket surfaces with something like lacquer thinner and use a new gasket every time you take it apart and put it together - NO SEALANTS!

The clutch? Might have to take it out and inspect all the parts to find the problem. Sometimes it's as simple as too heavy a grade of oil (I use 10W40 year round) - it might be a bad cable, broken friction disk, warped driven plates, deep wear notches in the fingers of the clutch basket, something loose or not assembled properly. Start with the simple - take the cable off and see how easily the inner wire moves within the sheath. It should slide freely without resistance just using your fingers to push and pull on it.

Good luck
 
1 - 5 of 5 Posts
Top