My son has been driving his new DS650 at night and has noticed that his headpipes glow. The tempuratures have been in the 20"s.
What changes need to be adjusted to the carburetor?

 

My headpipe glows sometimes to,i think it's because it runs to lean but i'm not certain,any help would be appreciated guys..

THANKS.

DSWOLF

 

You probably need to go up a main jet size or so. If we knew more info like elevation, any mods that you may have on your quad it would help.

 

My son has changed to a K & N filter and put on a HMF slipon silencer.
Changed the main jet from 165 to 170.
Changed the pilot jet from 45 to 50.
Raised the needle by moving the clip down one groove - which is the 5th and highest position you can raise on the stock needle.
Elevation is 1000 ft.

I headpipe glows most when just cruising around in low to middle range.
When he is in middle to top range the headpipe glow goes away.
I hope this extra info helps to diagnose his problem. Thanks.

 

Is that a mikuni or dynojet main? I would go up to a 175,177.5, or try a 180. I am running a 180 mikuni main now with my setup. Look at my signature. I think HMF ,on their website, says to go up on the main jet size, raise the needle one postion like you did and open the air/fuel mixture screw 3.5 turns out.1000 feet is about the same elevation that I ride. I didn't change my pilot jet though. These are just some observations.

 

HMF website

Look at performance tips for the ds-650

 

We went up to 50 on the pilot jet because at 3 to 4 turns out the spring is very loose and was worried that pilot fuel screw may vibrate out.
Being winter it has not been easy to do any high speed testing for optimum main jet, but it looks like going up to 175 should help.
Thanks for sharing your info.

 

Yeah, Temperature,humidity,elevation,equipment are all part of the tuning process. I wish is was cut and dry for all machines, but you know how that is. The best we can do, I think, is find a good starting place and then tune from there. I think there is an art to this tuning thing as well! You guys definetely have colder weather than us folks in Texas!

 

It could be from lean causing excess heat or overly rich with the gas burning in the headpipe. Also aftermarket pipes can me thinner and will also do this.

Smitty