Bonneville America Forums Forums Technical Forums Exhaust Header Wrap

I wrapped my headers last month and now I've noticed that once the bike is fully warmed up the idle speed jumps around. I'm guessing that means I need to adjust my A/F ratio. Does that sound like I need more air or more fuel?

Yes.

Seriously, how about a few more details?

i can't imagine that having anything to do with the wrap. what else have you done?

wrap not a great idea if your pipes are nice, if not then i guess its an option. Can change the tune, allot more scavenging going on and could lien out the engine. As mentioned though more info, headers wrpped, pipe, both? any other mods, filters, re-jetted? When you say bounce around, 100rpm 500 rpm? does it do this when you are only in idle or while riding? I am surely not the pro in here but those that are will want to know in order to better help you. PS.....i have seen header pipe turn nice pipes into mush in less then 18 months....... just saying :-)

Well the wrap's already on. The pipes were scratched up and blued and I wanted to black them out so I wrapped them. Just the headers. I did no other mods. The bike acts exactly as it did pre wrap except the idle fluctuates by about 250 rpms. This is the first I've ever heard of header wrap destroying pipes. I have the same header wrap on my 79 Ironhead and it's been on there for 10+ years with no issues. The idle will drop by about 250 rpms then cycle back up, but only when the bike is hot.

Did it start doing that immediately after you wrapped them or was it a few days later?
Im thinking coincidence unless you were yanking on the header pipes with force and maybe broke the seal at the exhaust port but then that would make it louder and probably show soot where the leak is.

Your not running an air box right? Just K&Ns.

High five on the iron head. From what I undestand, wrap only rusts pipes if they get wet without the chance to boil the moisture out. God knows what those iron head's pipes look like. Anyway, I think big Z is right: it sounds like you probably have a leak.

I have had wrap on my headers for a couple of years now and have had no problems with it all

Now that you posted this, my idle jumps around (I have wrapped pipes)...guess I never noticed it...

Keep talkin it up gentlemen, my idle jumps around as well and I do not have header wrap

Here is my guess on carb bikes: the intake conditions change and the fuel intake varies so the bike idle changes....you just noticed it when you put the wrap on the pipes...it was all way there...

I only noticed the problem immediately after I wrapped the pipes. I have no airbox, just K&N filters. My first thought is that it is a coincidence. I replaced the copper gaskets when I put the pipes back on and snugged them down very well with blue loctite. I'm going to fiddle with the A/F screws and see if that doesn't made a difference. I just wanted to get some other people's opinions before I started tinkering on it to make sure there isn't something else I might be overlooking.

I did the same as you...took the pipes off wrapped them, installed new gaskets and torqued everything...

Before it was surging, what RPM was your idle set?
Does it do it if the choke is pulled after its warmed up?

Idle was set around 1000rpms. If I pull the choke the surging stops.

Sound like you need a bit more fuel and maybe a carb balancing.
Have you cleaned your filters lately? Try that as well.

Good call. I recently cleaned the filters, so I doubt that's the problem. I turned my a/f screws a quarter turn out, and it feels a little better, but still surging. Next I went out and bought some vacuum gauges. When I went to balance the carbs I discover that my carbs don't have an adjustment screw where the service manual says it should be. In fact my carbs look just like the pics in the manual except for the adjuster. Anyone know where that sucker is located?

Its the screw on the inside of the right side carb, its got yellow paint on it.
On the bike its locate on the left side carb.

Turn your idle up to about 1500 when adjusting it. Its very sensitive to adjustment and pressure.

If you've never down it read Dinquas carb adjustment page here: Carb balancing

That's exactly what I was looking for. Thanks Z, I owe you a beer next time I see you!

Carbs synced, surging gone!

and wrap doesn't get the wrap for this one...