Hi there, my ancient machine (engine) starts to cough once running at operating temp. Only way to keep from stalling is to put choke on 1/2 to full. Engine seems to run better cold. Although after running for 5 or ten mins idle speed starts to fluctuate greatly? Just started engine from cold… it fired up then promptly quit had to restart which has been usual lately especially when temp is +5 deg celsius current temp or colder ever since carb was rebuilt with new jets etc last fall at Honda dealer. New honda carb not being made for my machine. Did check my batt got 12+ volts. Have replaced fuel pump in the past, could it be causing my problem? Read about cut out relay?? sounds complicated!!!! Also had CDI replaced about 2 or 3 yrs ago. Can feel pulse in pump. is there an easy way to check it? Any help appreciated!
Frustrated with the old horse.
Just for some info on this quad its an 02 400ex I have had for probably4 years now. I want to pass it down to my son who rides it (when its running already). Being its almost spring I am done with screwing this up.
I had a blown piston in the end of last year. The cylinder had some scratching so I picked up the next size piston from wiseco to make it a 416. I then mailed the cylinder and piston to have it bored/honed to match. I replaced the timing chain, and found my cylinder valve cover had a broken engine mount so I replaced that. I then found that my valve guides were out of spec so changed them, and did new valve springs, seats, seals.
Long story short I broke a tooth on my outer clutch basket and replaced it with the wrong year basket, it was hitting the gear and I didn’t notice. I also put my cylinder scraper and compression ring on upside down so they were in the right spot but upside down. Didnt realize that either… :icon_ cry:
So I had it all back together and it ran seemingly fine. It wasnt smoking or rattling or anything. I rode it around a few hours and changed the oil didnt see anything out of the ordinary.
I took it out again and noticed it was not really picking up in 4th and 5th gear, then all the sudden while in 5th it just shut off. I restarted it but it had no power, it started but when I throttled it would rev up but wouldn’t move an inch.
So I spent today tearing it down and found the upside down rings and a scratched up piston, nicked ring, and cylinder walls were slightly discolored in a small area.
So what in your opinion do I need to do to get this going again. Would the ring having a small nick cause complete power loss? When I had it in 1st I was able to roll it with out the clutch pulled? Now that its apart the quad wants to roll when the crank is rotated.
Do I need to get a new piston and have the cylinder honed again? Or just new rings? What else should I check for before reassembling this thing? Whats the best way to be sure the bottom end is all cleaned of possible metal shards?
