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View Full Version : Whats going on with my idle speed?

Red ones
28-12-11, 12:03 AM
Any ideas?

Cold mornings, I start the SV up, it starts at fast idle, then drops to around 1000rpm while the temp gauge is still off the bottom. Then the engine stops. I can restart, but need to hold the throttle gently open. When the engine is up to north of 25C the idle settles, and by the usual 40C it is running at around 1300 - 1400 rpm.

It got me. I have changed air filter (the old one was awful) I have changed the plugs, the old one was on its way out. i have played with the idle speed....

where to look next?
twowheels
28-12-11, 12:07 AM
it depends on service history, have the carbs been balanced and have the valves been checked?

id also want to look for any air leaks - including in the exhaust system
Sid Squid
28-12-11, 12:30 AM
As above, most likely is throttle balance, TPS and STV idle setting.
Red ones
28-12-11, 11:05 AM
Having watched and listened carefully this morning, I think the fast idle is wrong/non-existent.

I'll probably get the throttle bodies balanced and check the TPS. I thought it was advised to never play with the STV, but I might have that horribly wrong (I have left my workshop manual at home today.

If any one wants to volunteer to help me (and has a vacuum gauge) in the Barnet or Stevenage area it would be greatly appreciated!
Red ones
13-01-12, 08:49 AM
Best £45 spend on the bike in years!

Much smoother, I have a cold idle, YIPEE!
joshwalker094
13-01-12, 09:30 AM
What did you spend it on? Mine seems to be doing the same

Sent from my GT540 using Tapatalk
Red ones
14-01-12, 08:58 AM
I followed twowheels advice and got the throttle bodies balanced. I would have done it myself, but the gauges are about £80 and the garage only charges £45.

I don't think they have ever been balanced (at least I have never specified it) and the bike is an SK5 with 80,000miles on the clock.

Now the throttles are balanced, there is little indication the STV needs adjusting.

I don't think the TPS is too far out from factory setting, after all the bike now accelerates wildly when I roll on at 3,500rpm bringing back memories of nasty moments when it was new.