sputter problem been chasing for 5 months

[nick03]

ok first off bought the bike it had a bad sputter problem at all times. took it to a shop, they cleaned the carbs and synced them. i went and rode it every time i ran it wide open it would sputter and jump but would cut through it after a few seconds so i took it back they raised the needles and seemed to fix it until i got on the high way and was moving at 5,000rpm and decide to go wide open to pass and it sputters bad the shop says it is raised as high as it can go what else could it be. so if i am cruzing any gear and decide to go wide open it sputters but if i wide open from first on runs good ??? any ideas and replaced plugs (tips where really white) no difference tried pulling choke out will riding(no change) emptied tank cleaned and filled with fresh gas changed pet cock and cleaned lines (no change) ran seafoam though it (no change)

[DonTZ125]

First off, stop going to that shop - they have no clue about carbs. If you have bone-white plugs, you're lean to the point you could be doing engine damage.

Second, do a quick check to determine what you have in the way of: carbs, air filter, air box / pods, exhaust system, main jet size(s), fuel level. We can probably make some suggestions from there, but you're going to need to learn how to do some tuning. This link from Factory Pro is one of the better how-to's out there.

[nick03]

ok i should have mentioned it is the vance and hines special edition so it has full exhaust has a k&n drop in air filter and that is it i pulled the carbs off and found the boots under the carbs are all jb welded up i gess cuz of cracks so i am ordering those but somthing is telling me i should probably take the main jet out and see what size it is and i checked the needle and they are maxed all the way out

[DonTZ125]

Definitely check the main size(s) - they sound WAY too small. You may find the 2-3 mains are one size smaller than the 1-4 mains; this is not unusual. The 2-3s run hotter (less airflow around them), the mix is less dense, so less fuel is needed / desired.

[nick03]

i found a hole in one of my diaphragms if i was to buy a used set of carbs for a diaphragms will a 91 work on my 92

[nick03]

One of the jets say 525 and the other 106

[lawmer]

Don's prolly getting tired of me banging on about it. But a faulty ignition system shows it's first sign of weakness UNDER LOAD or WOT.

You now have downtime with you machine, so maybe use that time to inspect your ignition system. IMO the first port of call on any performance related issues/or none START, is to inspect the ignition system. Here's Dons very helpful link. http://fzronline.com/wiki/doku.php?id=no_spark_now_what

I noticed "i found a hole in one of my diaphragms" the shop missed that so yeah dump those clowns, Some clowns claim to be what they are not, I.E. Yamaha Certified Technicians, Please check out their credentials before you give the charleton your hard earned cash.

I've witnessed those who CLAIM to be a "Yamaha Certified Technician" suggesting in a possible low compression issue to well.... "Place your thumb over the plug hole, turn the motor over" I'm leaving it there for another day with him. I do know he is a clown, My warning is don't give them your cash for something you later need to rectify yourself.

If anyone is unclear. I hate anyone having to pay for an unsuccessful repair on their vehicle. Why should they the customer suffer if the "Technician" is dumb? No customer ever paid me anything if I couldn't repair their problem, reason. I always fixed it.