Stalling at idle and hard to start when warm

[yamahaggis88]

Ok, just got my bike back from a full service today including having the carbs balanced, power delivery is much more linear, no spikes or flat spots and no more missing near the top end. However I have a new problem, the idle seems to be set really low, and when warm the bike refuses to idle with the clutch in or in neutral, problem is worse with the lights on (which is all the time obviously). It's also bloody hard to start after it's stalled. It says on the invoice that one of the main jets was replaced and reinstalled in the correct position, as it was apparently wrong, then carbs balanced, mixtures set etc etc. Before I took it in the idle ran quite high, not sure how high as my tacho starts at 3k but it was a lot higher than it is and it would never stall on me, but had a fairly big flatspot from about 5-8000 rpm and it would miss. I installed new iridium plugs less than 1000km ago (NGK C8HIX or something along those lines) and they gave a marked improvement, but could they be the wrong plug for how the bike is now tuned? Pretty stumped and not too keen to take it back as I just wanna enjoy the damn thing now its legal and (almost) sorted...

[sinfull]

Ok, just got my bike back from a full service today including having the carbs balanced, power delivery is much more linear, no spikes or flat spots and no more missing near the top end. However I have a new problem, the idle seems to be set really low, and when warm the bike refuses to idle with the clutch in or in neutral, problem is worse with the lights on (which is all the time obviously). It's also bloody hard to start after it's stalled. It says on the invoice that one of the main jets was replaced and reinstalled in the correct position, as it was apparently wrong, then carbs balanced, mixtures set etc etc. Before I took it in the idle ran quite high, not sure how high as my tacho starts at 3k but it was a lot higher than it is and it would never stall on me, but had a fairly big flatspot from about 5-8000 rpm and it would miss. I installed new iridium plugs less than 1000km ago (NGK C8HIX or something along those lines) and they gave a marked improvement, but could they be the wrong plug for how the bike is now tuned? Pretty stumped and not too keen to take it back as I just wanna enjoy the damn thing now its legal and (almost) sorted...

Go top up with 98 and let us know the difference !

[yamahaggis88]

98's all I use...

[sinfull]

98's all I use...

You ride alot then ? I'd go back to the servicer then ! Not happy fix it!

[yamahaggis88]

I'm not meant to, but I do

And yep, looks like thats the way its gotta be, it sounds like its almost struggling to idle...

[Laava]

What happens when you turn the idle up a bit?

[racefactory]

If it's hard to start when warm, the low speed circuit in the carb is too rich. Your pilot jet/pilot screw/idle jet is set too rich... turn it in to make it more lean. Try a half turn at a time.


.... that or turn the idle up but I'm presuming you've already tried that!

Oh, and check your choke operation; does it open and close fully?

[DMNTD:Me]

If it's hard to start when warm, the low speed circuit in the carb is too rich. Your pilot jet/pilot screw/idle jet is set too rich... turn it in to make it more lean. Try a half turn at a time.


.... that or turn the idle up but I'm presuming you've already tried that!

Although you're possibly correct, best bet is to take it back to where ever it was 'serviced' and get them to have a fiddle. IE...give them the opportunity to remedy the issue, at no extra cost naturally

[NinjaNanna]

Although you're possibly correct, best bet is to take it back to where ever it was 'serviced' and get them to have a fiddle. IE...give them the opportunity to remedy the issue, at no extra cost naturally

Yep I agree, they've got everything else sorted, why not let them finish the job.

[yamahaggis88]

Rung them today, their guys on holiday til next week but they offered me one of their other mechanics to work on it (they mostly service tractors, but theyre a suzuki service agent, only one of their mechanics is qualified on bikes though, rides an SV), I said i'd wait, they said sweet, apologised, said it would be done at no cost as its a remedial and that was that, good buggers

[ducatilover]

Either the idle is set too low or as Racefactory said it's too rich.
If you decide to do it yourself, the pilot screw will lean the bike as you turn it in, only if it's on the engine side of the carbs, if it's on the airbox side of the carbs, it gets richer as you turn it in.

[kiwi cowboy]

Either the idle is set too low or as Racefactory said it's too rich.
If you decide to do it yourself, the pilot screw will lean the bike as you turn it in, only if it's on the engine side of the carbs, if it's on the airbox side of the carbs, it gets richer as you turn it in.

Its a gsxr400 so definatly on the engine side.
The only other thing you could check is the air filter and if its cleaned and too much oil or to thicker oil used in the foam could make it run rich.

[FROSTY:Me]

You cant do any harm turning the idle up half a turn