Mid-range hesitation 6k-7k

[Srengam]

Hi all,

I seem to be suffering with a hesitation during acceleration.

1st and 2nd gear seem fine, 3rd gear seems to simply "suggest" a problem but doesn't actually affect performance, it just sound a little different, but it becomes more noticable in the higher gears; the higher the gear, the more extreme it becomes.

When the needle hits 6k, it seems to struggle, a bit of juddering and bike seems to slow down for a small moment, almost like it's running out of fuel, as soon as the revs go above 7k, bike is fine again.

Any suggestions?

[jarvis]

Hi all,

I seem to be suffering with a hesitation during acceleration.

1st and 2nd gear seem fine, 3rd gear seems to simply "suggest" a problem but doesn't actually affect performance, it just sound a little different, but it becomes more noticable in the higher gears; the higher the gear, the more extreme it becomes.

When the needle hits 6k, it seems to struggle, a bit of juddering and bike seems to slow down for a small moment, almost like it's running out of fuel, as soon as the revs go above 7k, bike is fine again.

Any suggestions?

Thrash it in first then all the way through the box, that way you'll only have to go through the flat spot once......simples

[Srengam]

Thrash it in first then all the way through the box, that way you'll only have to go through the flat spot once......simples

LOL,

I suppose that's one work around.

[92xjunker]

That would be dumb.. try this http://www.factorypro.com/tech_tunin...m_engines.html

[scottynoface]

That would be dumb.. try this http://www.factorypro.com/tech_tunin...m_engines.html

[jarvis]

That would be dumb.. try this http://www.factorypro.com/tech_tunin...m_engines.html

OK so that would work although my method would be more fun lol

[arsenic]

Thrash it in first then all the way through the box, that way you'll only have to go through the flat spot once......simples

Make sure you use fresh gas when you do that.

[uncltommy77]

Clean the carbs I would think. Mine did that and was getting to much air. Rubber donut on filter box came lose. Put it back on the right way and no more problems.

[ManQu]

Thrash it in first then all the way through the box, that way you'll only have to go through the flat spot once......simples

Well it made me chuckle!!.......

[jarvis]

Well it made me chuckle!!.......

Thanks

Some people just don't appreciate my sense of humour

[92xjunker]

We had a member, I'm being nice today, post here before with the simular issue, turned out to be a float height adjustment, Maybe?

[Srengam]

Thanks all,

I'll give the linked guide method a try, I've never done anything to carbs before so it will also be a good maintainence lesson for me.

[Kreylyn]

Hi all,

I seem to be suffering with a hesitation during acceleration.

1st and 2nd gear seem fine, 3rd gear seems to simply "suggest" a problem but doesn't actually affect performance, it just sound a little different, but it becomes more noticable in the higher gears; the higher the gear, the more extreme it becomes.

When the needle hits 6k, it seems to struggle, a bit of juddering and bike seems to slow down for a small moment, almost like it's running out of fuel, as soon as the revs go above 7k, bike is fine again.

Any suggestions?

Generally speaking, 5-8k rpms is the main jet needle settings or issues. It could be as simple as adjusting the needle position or it could be worn/damaged parts.

I would personally start by checking/inspecting each spring under the top caps, the needles for wear or damage, verify all parts are there and properly installed (spring on the plastic seat that sits on top of the needle, small donut spacer under the eclip on the needle, so on...). I would also suggest checking the rubber diaphrams are in good shape with no holes or tears, and that they show no signs of being improperly seated and pinched by the cap from someone prior being in there.

Finally I would very carefully and closely inspect the needle jet portion of the emulsion tubes for wear as well. If those are worn, then you will get abnormal fuel dispersion and amounts in the 4-7k rpm range depending on the wear.

If you doing all this... I'd strongly suggest you go ahead and do a full cleaning and rubber check on all parts. Replace any rubber that is deformed, hard, cracked or "chipped".... A bad oring under the slide guide for example can cause all kinds of issues.

Krey

[Srengam]

I'm slightly confused here to be honest.

I've read through the linked tuning method, and i've looked through the service manual trying to understand.

Regarding "adjusting main needle jet", the service manual seems to suggest that this is not adjustable, during the reinstallation section it doesn't mention it being variable.

Also, the exploded diagram seems to suggest I have four of these to adjust, how would I know which one or more needs adjusting? Or I would I simply look for one that's clearly "in the wrong place / height" or damaged?

Also, I taken to the tank off, and I've got three vacuum inlet caps where they should be, but where the fourth should be, is a screw, screwed in instead? Clearly a botched job done at some point. I've ordered a new cap. (could it be this) I did have a dodgy mechanic do some work on the valves recently.

[arsenic]

First things first it's not the "main needle jet". its the jet needle. The needle jet is the emulsion tube. Don't worry, I get what you're saying.
1) The OEM needle is not adjustable. But a jet kit, either Factory Pro or Dynojet, the e-clip has grooves to go in. Therefore, the needle is adjustable.
2) you'd adjust them all.
3) highly doubtful, but if you know it's broke, fix it.
I'm not blaming you for calling it the "main needle jet", but that bugs me.