Hesistation Unles On Prime.

[toymechanic.]

I still have a hesistation unless it is on prime. The hesistaion is between 1500 and 3000 RPMs. I have three steps over stock on the pilot jet. I have the main jet needle raised an 1/8 of an inch. Out of everything I have done so far raising the needle has helped the most, so does this mean I need a bigger main jet.

[earlfor]

If you are running a stock airbox, filter and exhaust, there is no need change the pilots or raise needles. 1500 to 3K rpm is beyond the effective range of the pilot jets anyhow. 1/8" is a HUGE change. I suspect you are flooding the engine. Have you done a vacuum synch on the carbs. If you have not, youre wasting your time with jetting. You cant jet something that isnt flowing correctly in the first place.

Earl

I still have a hesistation unless it is on prime. The hesistaion is between 1500 and 3000 RPMs. I have three steps over stock on the pilot jet. I have the main jet needle raised an 1/8 of an inch. Out of everything I have done so far raising the needle has helped the most, so does this mean I need a bigger main jet.

[toymechanic.]

Yes I have done a vacuum sychronizing. The hesistation was worst until I raised the needles. It was getting better as I went bigger with the pilot jets. But this last change didn't help anything. It does have stock exhaust and air box but K&N oem replacement element. What do you mean by floating the engine.

[toymechanic.]

Oh yeah if I didn't mention it. The hesistation goes away with the brand new petcock on PRIME!

[fgh]

If prime is OK then a petcock problem

It would seem that if prime is OK then you must have a petcock problem or some blockage. I'm sure you've checked it all but one more look might be worth it. Do you have a vacuum actuated one that isn't properly connected or has some blockage in the line. Is the vacuum line connected in the right place. I guess the fault could also be a vacuum leak in the line or valve.

[earlfor]

I said "flooding" the engine. :-) If the only change you have made from stock is to install a K&N filter element in the airbox, installing bigger idle jets and raising the needles shouldnt be necessary, certainly not raising needles 1/8".
I said flooding because I suspected as the needles raise, youre getting too much fuel. However, if the problem goes away with the petcock on prime, then its not a carb jetting problem. Its a fuel feed problem. I would replace the vacuum line on the petcock, and then suck on the vacuum hose to be sure the petcock flows enough. Compare the flow on the prime setting to the run setting while youre sucking on it.

Earl

Yes I have done a vacuum sychronizing. The hesistation was worst until I raised the needles. It was getting better as I went bigger with the pilot jets. But this last change didn't help anything. It does have stock exhaust and air box but K&N oem replacement element. What do you mean by floating the engine.

[toymechanic.]

New Petcock

My petcock is new. Driving to work this morning, my hesistation problem is worse. and driving down the interstate, I'm now getting popping. I think I'm going to put everything back stock. Resoak the carbs and acid wash the tank. and get rid of the inline fuel filter. Could this be a coil problem? My hesistation is 1500-3500 RPMs.

[earlfor]

I would return everything to stock. There is no reason to make carb changes because of nothing more than an airfilter element change. That is not the cause of your problem. Check to make sure you have 5/16" fuel line too.
Also, I would get rid of the inline fuel filter. They have only caused me problems because most of them will not flow the volume of fuel necessary. There is no need for one anyway, because there is a filter screen in each carb and another large one on the petock. Toss the filter. It alone may be the whole problem.

I would not acid wash the tank unless you are going to line/barrier coat the inside with something such as PQR, etc. An acid washed and untreated tank will multiply any rust problem you have by 50 fold.

Earl

My petcock is new. Driving to work this morning, my hesistation problem is worse. and driving down the interstate, I'm now getting popping. I think I'm going to put everything back stock. Resoak the carbs and acid wash the tank. and get rid of the inline fuel filter. Could this be a coil problem? My hesistation is 1500-3500 RPMs.

[fgh]

Earlfor for GS God

I have to agree with Earlfor. It seems to be a fuel feed problem. Most inline filters are for systems with pumps and may inhibit the flow enough in a gravity feed system to cause your problem. I've never needed one in my bike. If you have doubts about the screens being in place certainly check that. The popping and hesitation sound like a potential vacuum leak. I had once reinstalled my tank and not hooked up the petcock vacuum line. That loss was enough to cause a moderate hesitation. I only drove about a mile to the gas station were the problem was corrected. If you've got a vacuum pump hook it up to the petcock and test for vacuum with the petcock on each setting. It should hold vacuum on all settings. Does it have the problem when the petcock is on the "Reserve" setting?

[toymechanic.]

update

I have not changed it back to stock but it hesistates in all position now with new petcock. The reason I wanted to acid wash the tank to to disolve the rust that is loose. Even with the inline filter I have rust residue in the bottom of the carbs when I remove them. A friend used citric acid the clean his tank and he said it disolved all the loose particles and everything and the tank is nice and shiney on the inside.But you guy think I should stay away from that idea though? My hesistation is getting anoying, poppoing and crackling all the time! I have sprayed all kinds of liquids around the intake boots area and I do not think I have a vacuum leak! My petcock is new from Suzuki!

Oh yeah my spark plugs are real black!

I'm not sure how the diaphams in the top work, but could it be that they are not lifting soon enough. Because once it gets to about 3500RPMs it takes off like a rocket ship!

[earlfor]

OK then. My take on the situation is we have a multitude of symptoms pointing to everything from the induction system to the carbs, petcock and now the ignition system. Basically, it seems we are resorting to the shotgun in the dark approach hoping to find something that will work. At this point, with so many conflicting indications, it is impossible to pinpoint the cause. I would start at the beginning.
1, Always verify the battery is in good condition and holding a minimum of 12.5 volts and preferably at least 12.8 volts.

2. Check resistance on the coil primary and secondaries. They should show 3 ohm primary and 30k to 50k ohm secondary. Plug caps should be 5k ohm each.
Voltage to the coils on the orange/white wire should be bare minimum of 12.v and preferably above 12.5v. with the headlight on.

3, Remove the carb rack and clean and reinstall the original jets.

4. Remove and discard the inline fuel filter.

5. Remove the petcock and clean the filter screen and clean the fuel filter screens in each of the float bowls.

6. Etch the fuel tank and coat the inside with a rust preventative such as PQR or Kreem. My opinion is etching is alone, not enough, Once rust starts, it will continue if nothing is done to inhibit it.

I believe your plugs are black because the jetting is too large now.

Earl

I have not changed it back to stock but it hesistates in all position now with new petcock. The reason I wanted to acid wash the tank to to disolve the rust that is loose. Even with the inline filter I have rust residue in the bottom of the carbs when I remove them. A friend used citric acid the clean his tank and he said it disolved all the loose particles and everything and the tank is nice and shiney on the inside.But you guy think I should stay away from that idea though? My hesistation is getting anoying, poppoing and crackling all the time! I have sprayed all kinds of liquids around the intake boots area and I do not think I have a vacuum leak! My petcock is new from Suzuki!

Oh yeah my spark plugs are real black!

I'm not sure how the diaphams in the top work, but could it be that they are not lifting soon enough. Because once it gets to about 3500RPMs it takes off like a rocket ship!

[snowbeard]

so brand new OEM petcock, eh? I had a similar problem when my diaphram leaked, I thought I had burned a valve or some such, as it would flood the #2 carb.

but it generally sounds like you're not getting good fuel flow, if it runs well on prime but not run. this could happen if there is poor vacuum to the petcock, or fuel flow is restricted either in the hoses, petcock, or perhaps even the float bowl. of course, again if it runs well on prime, I would suspect the petcock most of all, even new...

[toymechanic.]

very slight hesitation now

I put everything back to stock except the jet needle level, I put the plastic spacer under the circlip and the metal washer over the circlip, so I'm about .125 inch high. I also cut about a half an inch off of the length of the springs of the diaphram pistons. Now it doesn't have to raise as much vacuum the start lifting the pistons and jet needle! Anyone know if there is any repercusion to this?