Hey there . . i have a 98 F3 And The bike runs great at idle it revs just fine but when i take it out it starts bucking and jerking. ive rebuilt the carbs resynched them (on the bench) rebuilt the fuel pump and still having the same issue . . .ive jumped the fuel cut relay and no change, disconnected the air solenoid . .no change, ran new fuel lines with no restriction . .. no change . .my question is well . . several questions . . .how often is the fuel pump supposed to click when the bike is running? and is it possible when i synched the carbs i have it set to lean? any input would greatly help im starting to fear i will never be able to ride this season

 

yeah sounds like a fueling issue. it could be your fpr

 

im assuming FPR meens fuel pressure regulator . . . . .where might that be loacted?

 

On a fuel injected bike. Since your bike is carbed, it doesn't have one.

If you only synced the carbs on the bench, they are way out of sync. They have to be synced by vacuum. That could be a big part of your issue.

Once you get the carbs properly synced and it still acts up. I would lean towards a thorough ignition inspection. It sounds like you may be loosing spark at higher loads. this can happen with a weak spark. The weak spark will run the engine fine at ilde or a no load condition. The weak spark cannot keep up with the demand of the load on the engine. It is actually still misfiring at no load, you just don't notice it because the engine freely spins past the point, where the loaded engine has all the weight of the bike pulling back on it, then it bucks and jerks.

The fuel pump should only come on to gain pressure, then only as needed. As the float bowls empty, the fuel pump comes on and refills them. As soon as they are full, the float raise and close the needle to the carb inlet, which builds pressure on the pump, and it shuts off.

do you have any air box mods? a jet kit? an exhaust that is flowing too freely?

 

it has a D&D slip on been jetted but not to severely and no airbox mods, if by any chance what kind of ohms should be runnign through the coil to determine if its bad? or voltage however you would go about checking it, also i talked to the previous owner and he said it just basically did this to him on the interstate and he limped it home and screwed things up more then it got dumped in my lap . .any ideas? or is it still sounding like a ignition issue?

 

im also running premium fuel in the bike if that makes any difference . . . .im looking at any and all angles . .well trying to

 

ok just one more thing i forgot to add . . . .if i just lay into the bike i can get passed the bucking and jerking and slam thru the gears with some hesitation . . .BUT! if i dont feather the throttle afterwords the bike will shut off . . .it starts right back up though but its kinda scary

 

I'm gonna jump in here and give a few idea's here.
1. 1st off , as justasquid said , You need to set the carbs up at vacuum on the bike to sync them . With them on a warmed up running engine.
2. Check to see if you have a grounding problem ,,I.E. cut off switch as I had that happen after finding the previous owner wired up the switch without sealing the wires winding through the framework . And it grounded the pulse signal cutting the power intermittently . (bucking and cutting out at load)
3. The slider throttle plates operate on vacuum , the more air through the horn the higher it rises ,,unless ,, there's a leak in one of the carbs diaphragm. Therefore ,,go to step #1 ,,after warming the bike up read thai's sync'ing up your carbs segment. It shows you everything about it and helpful tools on making your own vacuum sync tool ! It's very cool!
4. a bad or weak spark from a bad coil . Don't go blaming the CDI box ,,a common mistake,,a costly one ,,most cdi box's work,,or don't ,,no real way to test one,,its running,,so it's a very small 1% chance that's the problem.
Best of luck to you ~87TurboBuick~ in tracing the problem out. Keep us in the loop Bro.

 

i will definately check the kill switch tonight and check all my grounds . . .im going to have to buy a synch tool . . .i have the specs for for the coils and the ICM and the ignition pulse generator so im going home with my multimeter and start testing things . . hopefully im not going to have to split the harness . . .could a low battery cause all of this? its not to low but not 100 percent . .ive also noticed the cluster light pulse kinda justa a little at idle

 

hey guys . .so i checked out several things and come to find out my coil packs are out of range . . . .i need 21-25 k Ohms with spark plug wire connected . . .i only have .0003 k Ohms . . .so im going to get a set of coils and let yall know how it turns out . .thanks for the help