Hey,

My sherco spitts flames ( it makes a bang and a big flash no flames that burn for some seconds like on a superbike) out of the exhaust when i rev it and then close the throthle. (Bit like a chopper that is set to rich) The flame is up to 20 cm, anyone an idea what is causing this and is it dangerous for my bike?

my toughts are:

exhaust valve that closes to late

mixture to ritch (wat are the standard settings on this bike, airscrew, jetsize, ... )

ignition timing not correct

bike still ride ok no other problems just idle speed that is not constant the same (it drops )

any help would be welcome

regards bob

Sounds a bit rich, what year bike? Which carby? Have you checked the float levels?

SOUNDS COOL!!

Hi

Have you checked its not drawing air round the carb rubbers , also if the carb has an enrichment circuit check this is not blocked. Mine does the same if i leave the carb rubbers slack.

cheers

greg

its a 2007 bike with keihin carb

i'will check the rubbers on the carb, what should floathight be?

any idee on jetting for the bike?

greetings bob

Gday, sometimes this will happen when you have an air leak in the exhaust system too. Easy to check before you remove the carb.

Cheers,

Stork

just checked no air leaks at the carb or the exhaust

how do you messure float hight (pkw keihin carb)? what should it be?

jet sizes for the bike? (2007 3.2)

air screw is set on 7/8 out

regards bob

Stock jetting on the '08 was a 42 pilot, not sure about the main, probably around 125.

The Float setting should be 19mm, or basically level with the bowl sealing surface when held at a 45 degree angle to just close the needle. I think!

I think the airscrew setting sound about right, although they are sensitive and this can change with the day.

PM Borus if need be to see, if he does not pick up on this thread!

Wayne had the '08, then went to the PMS(note new slang) carb off the '09, but no mention of any great changes in jetting or level setting, as the new one just has a deeper bowl and stuff to go along. He tried the 45 pilot , but I think he went back to the 42/

Edited November 30, 200817 yr by copemech

hey thanks for the info,

ive put it on 19mm

its beter now

pilot 48 (bo big ?)

main 120

slide 4

runs ok now starts good and less fire out of the exhaust

The new SPS carb came with a 45 pilot, that is the one that I used in the original carb.

When I took the 08 to RYP for shipping Ryan started Cody's 09 and showed me how it shot fire out of the exhaust, I told him it was lean and he should adjust the air screw. The air screw was set at around 1 turn out, we set it at 1/2 turn and it was much better. The factory says the air screw should be set at 1/2 - 3/4 turns out.

Wayne