NEED HELP gsxf 750

[Raiznkain]

HIi guys and gals, im working on a 98 gsxf 750,,, the bike runs great when warming up,,,ride about a couple miles,,,it starts running like its loading up at lower rpm's,,crack the throttle to 3/4 open or so it cleans out,screams,let off to lower rpm's it sounds like it loading up again,,runs terrible,, tank cleaned,,fuel cock cleaned carbs went through and cleaned, checked plugs they are nice and white,,,still same problem,,im lost lol,,,any help appreciated thanks

[Kreylyn]

Any mods to the carbs, air filter, or vacuum system?

Krey

[Raiznkain]

Reply:

Hi,, no mods to the carbs,,,,stock type air filter,,,when the engine cools for ten minutes or so,,,then it fires up instantly,,,same thing,clean smooth through all the gears,,,,a mile or two,,have to nurse it back to the shop,,,plugs clean,,,no sooting or fowling,no mods to the vacuum,all stock,, you have a great bike by the way,,,i love the mods you made to it,,,id like to convert my swingarm for a bigger rear wheel,,,ill just have to wait a bit,,,

thanks again for the quick response

[suzukiray]

If you have an extra key, stick it in the tank lock & go for a ride. As soon as it starts acting up, open the gas cap. If the problem goes away right then, you have a vent issue. If not, you have elininated one of the possibilities. Ray.

[Kreylyn]

If you have an extra key, stick it in the tank lock & go for a ride. As soon as it starts acting up, open the gas cap. If the problem goes away right then, you have a vent issue. If not, you have elininated one of the possibilities. Ray.

This... If it's still doing it, also switch the petcock over to prime, and verify if it's still doing it as well.

Krey

[Raiznkain]

Reply:

Hey guys,,,great tips,,,also checked the vacuum tube from the petcock to the carb,,,found a very small crack along the tube,,,changed the hose,,,ran great for about 30 minutes,,,,ran it through the rpm's strongly,,,ran good,,,then out of nowhere it just shut down and quit,,,i had put a clear fuel filter on it when i changed the vacuum hose,,so i could watch the fuel flow to the carbs,,,i checked the venting issue,,,the vent hose from the bottom of the tank doesnt seem to have any clogging issues,,when it shut down,,i coasted to the side of the road,,,i checked the see through filter,,,it was dry,,completely dry,,,i put it on prime,,no flow,,,,i took my fingers and squeezed the hose like i was priming it and fuel filled up the filter again,,,i tried to start it,,,fired right up,,,nursed it back home,,,,im totally confused now,,,lol,,,,im sorry to ask so many questions,,but this issue is driving me crazy,,,,,thanks again for all the help,,,,,

[kevin2502000]

Make sure the hoses aren't kinked or too long. If the lines are too long it can make the fuel run uphill which we all know doesn't work so well. Keep the hoses as short as possible without kinks and not too tight as well. Find the balance. Also pull you petcock off the tank, there is a screen in there that could be plugged.

[The CyberPoet]

The fuel filter needs to be installed virtually at the carbs, so it's are virtually perfectly vertical -- if the filter lays on it's side (even part-ways, like at a 45 degree angle), it'll trap a big air bubble in there and be unable to flow fuel correctly. The last bit of hose at the carbs on the 98+ has a flex-shield around it -- I find you may actually need to trim some of that shield away to get the fuel filter into place well.

Also note that aftermarket fuel filters may not work for you (insufficient flow or too large to sit vertically enough).

Cheers
=-= The CyberPoet

[Kreylyn]

Yep, definately a fuel flow issue.

You probably fixed one issue by changing out the vacuum line that was cracked, and then at the same time added an issue by putting the filter on there.

Pre Kats have issues (just like you experianced) with inline fuel filters. CPs advice on moving it closer to the carbs may help you get it to work, but I can't promise on that.

Krey

[Raiznkain]

Reply:

thanks,,, you guys,,,are the best,,,sounds like a good diagnosis on the filter problem ill get right on it,,,thanks again for all the help