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XLinAL
21st June 2008, 17:37
Went to the Smokies last wkend. The bike ran great, until...Sunday.

Heading home, the bike started and idled fine until it was fully warmed-up. At a stop lite, it was idling at lot higher than normal and a little rougher too. It ran fine, just idled funny.

This continued 'til we stopped for lunch. After it had cooled down a little as we ate, it idled normally again. Until it got hot again. Then the same funny idle.

It ran fine. The temp on the oil dipstick stayed normal (around 210-230). I didn't notice any pinging except on a short run when I romped on it. ( I did have earplugs in for most of the trip so I might have missed more pinging). At the next stop I did go 1/2 turn out on the mixture screw. It had no effect on the idle problem>

My question is: what could cause this and what do I need to look for to fix it?

Background:
2001 883>1200 w/ Wiseco 10.0:1 dishtops
SE breather and Bassani Prostreets
TT single-fire ignition & SF coil
worked-over 883 heads and stock cams
It's been in this configuration for awhile w/ no problems.

I did the 35k maintenance b4 the trip. Syn3 and Formula + or whatever the new tranny lube is. I put 10R12 plugs in instead of the 6R12's I have been using ( 1 range colder). I put around 100 miles after the maintenance b4 the trip and no problems.

A friend had an emergency on Monday, so I haven't had a chance to look at it yet.
I want to do cams next, but not until I get this fixed.

Any help is appreciated.

Fe Head
21st June 2008, 18:45
Assuming the throttle cables and throttle plate is fully closing - you may have an intake leak that is allowing a lean miixture from more air getting into the engine. You can reset each clamp and check all the connections using the propane gas torch test to see if it shows up anything when hot and idling fast.

The fuel temperature in the float bowl should not be so excessive as to cause an increased vapour pressure to add fuel but it is a possibility if nothing else prove up as the cause.

Cheers;

XLinAL
21st June 2008, 18:56
Assuming the throttle cables and throttle plate is fully closing - you may have an intake leak that is allowing a lean miixture from more air getting into the engine. You can reset each clamp and check all the connections using the propane gas torch test to see if it shows up anything when hot and idling fast.

The fuel temperature in the float bowl should not be so excessive as to cause an increased vapour pressure to add fuel but it is a possibility if nothing else prove up as the cause.

Cheers;

I checked the throttle/ idle cables and throttle plate when I adjusted the mixture screw.
I checked all the fasteners etc. when I did the maintenance. I'll double-check for leaks when I get a chance.

Thanks