98 Sportster S, Help? Me too! Harley Sportster Ironhead Discuss 98 Sportster S, Help? Me too! in the Harley Sportster & Buell forums; I got carb problems: After warm-up, I can't get a "good idle speed" and when I come off idle to start to open the throttle it engine starts to stall, ...

[Marty Winger]

I got carb problems:

After warm-up, I can't get a "good idle speed" and when I come off idle to start to open the throttle it engine starts to stall, and then I have to goose it to keep it running. I have about 5K on the bike. I took the carb accelerator a part and the rubber looks good-any suggestions?

Thanks anyone!

Marty W

[HarleyCruiser]

Marty what have you done to the bike, is it stock, or have you changed the exaust and intake air cleaner to a free flowing one.
If so have you rejetted?

Originally Posted by Marty Winger

I got carb problems:

After warm-up, I can't get a "good idle speed" and when I come off idle to start to open the throttle it engine starts to stall, and then I have to goose it to keep it running. I have about 5K on the bike. I took the carb accelerator a part and the rubber looks good-any suggestions?

Thanks anyone!

Marty W

[frisco-rigid]

Hi Marty

Couple questions first..

Has it done this during the whole 5K that you've been riding it or is this a NEW symptom/prob.?

Have you done any Mods to it like Air Cleaner or exhaust or fiddled with the timing or Anything at all..??? If yes,,,,, did this prob start After any of those Mods..?

Here is my first guess----
If this just started very recently and you have NOT done any Mods or fiddling my guess is that an intake leak has recently occured..

If however this prob has always been a bother I will guess that the carb needs to be jetted properly and idle mixture should be adjusted properly AND I would still spray it to check for Intake leaks..
And it's alway a good idea to check and confirm that the timing is correct-- timing should be completed before jetting is finished..

When you answer those questions and also provide ANY other info you think could be important we can start getting closer to an answer instead of guesses..

[street bob]

That really sounds like an intake leak.

[Marty Winger]

Well here's what I did (so far). I took the top off and found I have a NOKT needle so I'm assuming it's stock without finding any reference to it, added a couple of small washers under the needle and put it back together...seems OK, but it looks like I'm going to need to adjust both the idle speed (it's about down to 650 RPM, andadjust the (inside) mixture needle too.

M

[HarleyCruiser]

what idle jet are you running, have you drilled out the idle adjustment plug yet?
When you talk about the accelerator, are you talking about under the bottom of the carb or on diaphran under the cap on top of the carb?

Originally Posted by Marty Winger

Well here's what I did (so far). I took the top off and found I have a NOKT needle so I'm assuming it's stock without finding any reference to it, added a couple of small washers under the needle and put it back together...seems OK, but it looks like I'm going to need to adjust both the idle speed (it's about down to 650 RPM, andadjust the (inside) mixture needle too.

M

If you took the top off, you might have done what I did and resulted in the same poor performance, I tore the rubber on the vacumn piston when I put the cover back on. I could not get it to start from a stop after choke off without bad backfire and/or stall.