Page 1 of 2

Running rich?

Posted: Mon Aug 24, 2009 2:37 pm
by therefused
I think my bike mite be running rich?

Problems are, when started it idles fine, but bogs abit at 4k, fine after i have gone down the road. after its warmed up it idles at 2.5-3k.

When i let the throttle off it almost always backfires.

Finaly, it sometimes cuts out when its wet/raining, just like its run out of petrol, its hard start after, but once its started i have to hold the revs at about 3k for 5mins then its fine, if i try rev it past 3k before 5mins it bogs and cuts out again.

Rim of the endcan is also jet black in burnt oil/petrol, nt sure which one

Any ideas?

Re: Running rich?

Posted: Mon Aug 24, 2009 8:19 pm
by Neosophist
I recommend you strip and overhaul the carbs.

Your bad mix could be blocked jets. Once you've given the carbs a once over and made sure everything is as it should be go from there.

Backfires (check exhaust system for leaks after you've checked carbs)

Re: Running rich?

Posted: Mon Aug 24, 2009 10:03 pm
by therefused
Will a leaking exhaust cause any other problems apart from backfireing?

Also in regards to carb pilot screws, is clockwise/screw in making the carb leaner or richer?

Re: Running rich?

Posted: Tue Aug 25, 2009 8:04 am
by Cammo
therefused wrote: Also in regards to carb pilot screws, is clockwise/screw in making the carb leaner or richer?
Screwing them in is a leaner setting, out is richer.

Re: Running rich?

Posted: Tue Aug 25, 2009 7:00 pm
by griff488
If you screw the pilot screw all the way in how many turns out should it be for the right mixture?

Cheers Griff

Re: Running rich?

Posted: Wed Aug 26, 2009 2:38 am
by The Hamster
Griff- between 2 and 2.5 turns out from fully in is usually where the bikes run nicely. I would go for 2.25 to start and just tweek them a bit if you feel the need.

Re: Running rich?

Posted: Wed Aug 26, 2009 5:42 am
by griff488
Cheers mate!
I have the same problem as therefused. Runs lovely on tickover, bogs down around 4-5k then ticks over at 2.5/3k revs! No back firing though! You can smell it running rich so will have a fiddle when i get chance! If not looks like another set of carbs to clean! Just done the missus' gixer!!
Are there carb rebuild kits easily available for these carbs? I used NRP carbs for the gixer ones!

Cheers Griff

Re: Running rich?

Posted: Fri Aug 28, 2009 12:58 am
by Neosophist
you can get float bowl seals if you need them, i only change them when they leak rather than a matter of course as there a rubber band rather than a gasket.

Other parts like floatpins etc are available but costly.

Maintaince is easy on them but fiddly getting them in and out due to the V of the engine.

Re: Running rich?

Posted: Fri Aug 28, 2009 11:06 am
by therefused
Checked my needles and they have a washer, if the mod has been done they will have 2 washers am i correct?

Re: Running rich?

Posted: Sat Aug 29, 2009 2:54 pm
by Neosophist
therefused wrote:Checked my needles and they have a washer, if the mod has been done they will have 2 washers am i correct?
Check the size of the washer.

It could have 5 ultra thin washers, or 1 thicker washer :D

:)