DR650 hot header

[dvs182]

Posting for a friend of mine. He just bought a 01 dr650 with a gixer can on it. After an idle and warm up and throttle application the header at the cylinder side get glowing dull red. Is this a normal thing for them i dunno cause my husky had stock exhaust and never glowed.

Thanks in advance.

[Piercemcn]

Not normal. This is how to fix it.

Whoever put the gsxr can on didn't install a larger jet. Check to see if the airbox is opened up (remove side panels and seat) also. If so, both the exhaust and airbox being opened up lets more air in and out of the engine.

The more air you add to the equation, you need to add more fuel. This is because burnt fuel (exhaust) has substance, and absorbs heat like humid/ rainy wind instead of dry wind. Exhaust carries a lot of heat out for you. In order to fix this glowing header, you need to change the mixture. When I did my D&G exhaust I went from the stock 140 main jet to a 152.5. The DR650 runs very lean from the factory to pass emissions tests etc. so adding the gsxr pipe only makes it run leaner. Go to your local bike shop and get all the sizes from 145 up to 152.5 (4 jets will cost less than $20) and try putting the 147.5 first, without touching any other adjustments. Once the red hot header goes away, continue in your search for a smooth idle and smooth power delivery.

The red hot header means you are running so hot you are in danger of warping your exhaust valves.

Once you have the float bowl off the carb, you can access the main jet right there. You need a very short flathead type tip from a "quick pick" screwdriver to take it out. The round bushing you see with come with it. Keep the bushing, replace the screw, prime the carb (with petcock) and start it up. You will need to remove the tank and loosen the carb on both sides.

Check out this link also:

http://www.advrider.com/forums/showthread.php?t=347184

[zig06]

I'd also like to add that normally just changing the muffler on a DR650 isn't enough to change the jetting this is because the air box on a DR650 is the big restriction.  This spring I personally will be opening up the air box and installing a JD jet kit this spring on my '03 DR650.  FYI the GSXR muffler install on a DR650 is VERY popular and well worth the hassle to make it work.

[Piercemcn]

I'd also like to add that normally just changing the muffler on a DR650 isn't enough to change the jetting this is because the air box on a DR650 is the big restriction. This spring I personally will be opening up the air box and installing a JD jet kit this spring on my '03 DR650. FYI the GSXR muffler install on a DR650 is VERY popular and well worth the hassle to make it work.

Sounds like fun! I personally would go with the Procycle kit, because it comes with the extended fuel screw for about the same price. After having been through this project already, I wish I would have started with the extended mixture screw.

[jjktmrider]

If it's running hot at idle, changing the main jet won't do anything for it. The pilot jet needs to be bigger, plus a bit more on the mixture screw.

[Piercemcn]

OP states "after idle and warmup and throttle application". Before changing pilot jet, exhaust all options with fuel screw positioning.

[zig06]

This is turning into a big can of worms, the OP is in British Columbia which is a fairly big area (bigger than California, Oregon and Washington ~ combined!) which really means that "right now" he could be riding in 50 or 60 degree F weather or below 30 degree F weather...  Even worse, it could be so cold outside that they are just running it in a garage to check it out ... and with zero air flow even a properly jetted bike would make the header glow. 

 

So, could the OP at least tell us what the air temp is that the bike is running in "AND" is he actually riding it down the road or just rev'ing it up in a garage?  Inquiring minds need to know.

[dvs182]

Was probably about minus 5 degrees Celsius. And just reving the bike as there still ice and gravel everywere.

[dvs182]

And not in a shop outside

[jjktmrider]

Well that does change things a bit. Under those conditions it could start to turn the pipe red even if normal. All my quads will do that also if I'm revving but not moving and those I know are right. It'll be running a bit leaner in those temps though. Any popping when decelerating?

Edited February 22, 2015 by jjktmrider

[dvs182]

Yes

[jjktmrider]

Popping when decelerating is a sign of a lean condition.

[Piercemcn]

I don't think a "properly" jetted bike should ever have a red hot header, especially being oil cooled and having a 9.5:1 compression ratio. If your header looks like that, so do your exhaust valves, and parts warp and wear out real fast from constant heating and cooling like that.

[zig06]

But most bikes are not properly jetted for -5 C (about 23 degrees F), I seem to think that most bikes are jetted for something closer to 60 to 80 degree F ~ and moving.  So I'm thinking that "for now" there's nothing wrong, they just need to stop running it without riding it.  Sure, if you are working on something and you need to start it then fine, fire it up!  Just remember that you can over heat it.  And considering that even at a slow 25mph pace the bike is still getting hit with a 25mph wind, and that's a lot of cooling air.