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Discussion Starter · #1 · (Edited)
i have my friends quad here that is driving me Nuts. 07 450er.
brought to me in boxes. 3 local shops could not get it to run or didn't want to work on it.
I picked it up and the last motorcycle shop here in town.
its been apart for 7 years.

it would not run. the last shop took the motor apart and said they cant find a reason way its not starting.
I worked on it for 2 month off and on and it all came down to the Spark plug cap resister being bad.

it ran but was never 100%. it would pop and sputter from time to time.
he road it around for a few months and it stopped running again.

so we took it completely apart to see what has been done by other people.
we split the cases and put a complete new motor together.

New crank, top end, valves, starter, stater, exhaust, coil and boot and ecu.
put it all together and it started it. it has a bad lag and pop/sputter at 1/8 throttle.
and has a bad lag sputter on top end.

he said it started doing that before it died.
i pulled the carb apart to try to jet it.
this carb dose not have an adjustable needle.

someone has put a plastic spacer under the needle clip to raise the needle.
i removed it and have jetted from the 120 main all the way up to 190 main
ran harder but still has issues.

i jetted down from the 42 pilot to a 40 and up to a 48 pilot. no change.

i bought a tuned ecu and cut and spliced the throttle switch. starts better but still has the sputter/popping issue.

if you touch the throttle at all it will not start. its like its flooded and backfires, then it will start if you let it sit for about 10 minutes.
. you also CAN NOT use the choke at all, it acts the same as above.

from what i have read on line. this year Honda went to a 42mm carb. it seam's like a lot of people with this year have the same problem.
I have read that people have put a 39mm from a Yamaha and had good results.

just talked to sudco and a new fcr39mm is over $700.
I have been burnt too many times buying crap off of ebay and will not go that wrought.

i have cleaned this carb 5 times.
all passages are open. someone did put an adjustable fuel screw in it and the tip looks ok.

throttle and carb switch's were adjusted by the book before i cut and soldered them

I am beginning to believe this may not be the original carb for this quad other than it having to correct plug ends on it..

I am hoping to hear what you guys think before he spends that kinda money on a carb and or what carb he can use.

2006 trx 450er. Stock motor, sparks full exhaust, elka legacy series shocks, and many more boltons!!
466 Posts
What about putting on the 06 carb? 41mm I believe, same carb on trx 250 as well. It’s a good carb
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