Jump to content

Recommended Posts

Man I want to rip so bad I just bought this bike clutch was toast replaced it.  Bike starts cold 2nd kick idles great low revs great bogs out mid range. It is spitting fuel into the air box i cant see where from. Re jetted it with a jd jetting kit per instructions it is a little better it's like about to get into poerrband and blah let off it catches up then blah it does not die I adjusted the float height and it is better but not 100% the vforce Reed petals are in great condition. A new plug why is this thing spitting I do t want to take it to stealership but dang please help. Do I need a small main jet? Less fuel? It smokes not outrageously. It's a keihn 38 I believe. For the life of me I cannot find the factory specs for the idle and air screws either. Thanks in advance for the help.

cheers

20170819_180356.jpg

Share this post


Link to post
Share on other sites

Drop the needle two positions

If you are getting 'fuel spray', your emulsion tube (needle jet) in the carb is worn out.

When did you last replace the reeds?

Edited by THE KRAN

Share this post


Link to post
Share on other sites

I just got this bike it looks like it definitely has some hours on the petals are good from inspection but the boot has some weather checking on it. You mean drop the clip toward the point of the needle?

Share this post


Link to post
Share on other sites

Ok dropping the tip of the needle creates a richer or leaner mix? I'll raise it 2 right now 

Share this post


Link to post
Share on other sites

I can get to about 1/2 throttle and it bogs I'm at the last clip on the lean needle from jd's kit it still spits not as bad but it still bogs out and I adjusted the pilot air and idle while hot those seem right on I may just buy a new carb 

Share this post


Link to post
Share on other sites

>>If it idles, and the air screw works best when you have it around 1.5 turns, that's it, you have the correct pilot jet size.

Do not randomly turn the air screw.

Start with a really low idle and the air screw nearly all the way in, and turn it OUT to raise the idle. Stop turning when it stops raising the idle.

If that is about 1.5 turns out, you are done. Fine tune for cleanest blip and idle.

If you keep turning OUT and it keeps going up, your pilot jet is TOO BIG. 

 

If it transitions to partial throttle, under load, without a flat spot or a burble, the needle is close.  If it's flat, it's lean, if it burbles, it's rich. Don't change it, just move it up or down.

If at 1/2 throttle or higher, under load above 4krpm, it should run clean. If it's flat, the main is too small. If it burbles, it's too big.

If you find you have to change the main because it's too big, you have to re-visit the needle height. More than likely, it will go back up.

 

All of this is assuming you are tuning at the elevation AND air density of the day.

BUT,  on a bike that old, the reeds will be TOAST, and need replacing. You dont' wait till you see wear on the reeds....that is waaaaay past when you should have replaced them. 

Edited by THE KRAN

Share this post


Link to post
Share on other sites

Thanks man all great info they are after market v force reeds but you are right I have no idea when they were installed.

Share this post


Link to post
Share on other sites

usually if cracking the throttle open causes it to bog then the main jet is too lean.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×