re built my 2003 Suzuki LTZ-400 but...

[stihlman441]

so i had my engine out last year all apart, i just put it in and it runs great, but after 1/8 throttle it has a bog/stutter even in neutral, like when u drive too fast in reverse, i checked all my wires but still cant find the problem, any ideas would be helpful

[outlander560]

wat kind of atv and wat kind of engine is it?

[DirtDemon]

It sounds to me that you need to check your jetting. Sounds like you may be running a bit rich. I would start with the needle, maybe raise the clip one spot see if it gets better or worse. Your timing may also be off. I would check that first. Then move to the carb. It would also help to know exactly what you are working on. Year, make, model and engine size please.

If stihlmann ads the atv info could a mod move this into the appropriate forum please.

[mywifeknowseverythin]

I moved it in here......When the Brand is added you should be able to move it around.....

[stihlman441]

sry guys, its a 03 suzuki z400, all stock except for intake, do u guys kno what shims i would need for a stock z400, this mechanic told me it might be those b.c i lost my old ones

[DirtDemon]

Thanks MWKE.

When you say shims, do you mean for the valves? I would just buy a kit with different sizes for your machine, it will be good to have some different sizes for when your valve clearance gets out of spec. Your local dealer will be able to help you with that, and I would also recommend buying a manual for your quad. If you lost the valve shims, then that is most likely your problem, I wouldn't start that thing again until you get those replaced. Also, if you modified the intake, the carb will probably need to be re-jetted a bit richer to compensate for the extra air flow.

Edited July 1, 2009 by DirtDemon

[Ajmboy]

so i had my engine out last year all apart, i just put it in and it runs great, but after 1/8 throttle it has a bog/stutter even in neutral, like when u drive too fast in reverse, i checked all my wires but still cant find the problem, any ideas would be helpful

It also sounds to me like you need to check your jetting...but I'm going with not enough fuel as you changed your intake and all. You may need to increase your jet size.

[PROFILL]

If you have only just rebuilt the motor and done a airbox mod at the same time. you should undo your airbox mod and put it back to standard before jetting the motor or fixing the problem.

There are alot of LTZ400 bikes that have sudden running problems with the snorkel removed or even the airbox lid removed.

it is due to the type of carbi, as the CV carbi needs an amount of airbox restriction to lift up the slide in the carbi. All CV carbis can suffer from this effect.

just what type of airbox mod did you do?

remove the snorkle only or the lid as well?

but regarding the "missing shims" did you loose them and replace them? or do you know that you did not put them back in the motor?

If they are missing, there would be a very loud tapping from the buckets bouncing up and down with the 4mm gap between the top of the valve and the cam.

I suspect that they are not missing, because you would be asking "why is my bike making this noise???"

But if in doubt, go back and check what you last did to the motor.

also undo the air box mod, get the bike running like it used to first.

then open up the airbox and do jetting once you know the bike it right.