Rough Idle After Hwy Riding

I've seen this posted before, but can't find a posted fix:
After an hour doing 75mph on the freeway, I exited and was doing 30mph thru town. Every time I stopped at a red light, the idle dropped off, and the bike would stall. I could keep it going by blipping the throttle, but couldn't get it to steady up on it's own.
I thought I might be out of gas (I was almost at the end of my range), so I flipped to Reserve. No help.
This is the first time this has happened - runs great at speed, but won't idle.

After it cooled down, did it run fine again?

If so, that is the classic symptom of valve clearances reaching their limit. When did you check the clearances last?

When the engine is hot, the valve stems get longer. If your clearances are too small, the valves no longer seal until the engine cools down. When cold, it should start up and run fine.

If you leave this condition too long, the valves will burn and you will have permanent damage.

That was the same problem I was having.went through and had to reshim the valves for they were to tight.After doing this I have had no problems with engine dieing
after running at highway speeds. I went with .004 of an inch on the intake and .006 on the exhaust.

Good luck and take your time as for getting the cam timing off when when reinstalling will bend valves!!!!

When similar happened to me it was crud in the carbs and everything out of sync.

Could also be your vent hole is plugged in your gas tank. Try riding around with your gas cap unlocked (but make sure you don't have TOO much fuel).

If that helps, there is a vent hole in the gas cap. Get a wire and clear any blockage.

Corith wrote:

Could also be your vent hole is plugged in your gas tank. Try riding around with your gas cap unlocked (but make sure you don't have TOO much fuel).

If that helps, there is a vent hole in the gas cap. Get a wire and clear any blockage.

If the fuel-tank vent was blocked I don't think he could do 75 on the highway for an hour.

I haven't checked the valve clearance since last spring. But that was only about 3000 miles ago. Had about .004 (intake & exhause) then. I need to spend some quality time with the bike this weekend, so I'll pull the cover and check them again.
BTW, yeah, once the bike cooled off, everything was fine again.

.004 sounds low for the exhaust. Does any body know what the spec should be for a 900 LTD?

...is it same as Rammy's 650?

Post edited by: loudhvx, at: 2006/04/12 23:38

loudhvx wrote:

.004 sounds low for the exhaust. Does any body know what the spec should be for a 900 LTD?

...is it same as Rammy's 650?<br><br>Post edited by: loudhvx, at: 2006/04/12 23:38

Sorry about the delay on a response but that is exactly what my bike was doing and I would bet that the clearances and too small.I reshimed my valves and the problem is now gone.You can do yourself a favor and go just a tad bigger on the valve clearance than what the manual says by a couple of thousands it will not hurt the performance at all as for that is what i did after talking to a couple of local guys that have been doing this for years.As I noted prevesly run the intake at .006 and the exhaust at.008 of an inch and it should take care of your problem.A good rule of thumb is to run the exhaust clearance .002 or .003 of an inch larger than the intake as for the exhaust will grow a little more because of the heat.

Good Luck

Post edited by: rammy, at: 2006/04/13 22:03

rammy wrote:

loudhvx wrote:

.004 sounds low for the exhaust. Does any body know what the spec should be for a 900 LTD?

...is it same as Rammy's 650?<br><br>Post edited by: loudhvx, at: 2006/04/12 23:38

Sorry about the delay on a response but that is exactly what my bike was doing and I would bet that the clearances and too small.I reshimed my valves and the problem is now gone.You can do yourself a favor and go just a tad bigger on the valve clearance than what the manual says by a couple of thousands it will not hurt the performance at all as for that is what i did after talking to a couple of local guys that have been doing this for years.As I noted prevesly run the intake at .006 and the exhaust at.008 of an inch and it should take care of your problem.A good rule of thumb is to run the exhaust clearance .002 or .003 of an inch larger than the intake as for the exhaust will grow a little more because of the heat.

Good Luck<br><br>Post edited by: rammy, at: 2006/04/13 22:03

Thanks Rammy. I agree, I try to hit the largest limit of the clearance to get the longest duration between shim changes.

No problem that is what we are here for is to help one another.I went for a nice long ride last night and got the engine REAL hot and after running for 75 to 110 mph for about 10 miles or so and every thing was working fine and no problems.So that will let you know that the masurements I gave are all good to go and do work.

Good luck on the adjustments and take your time as it is very tempting when it is nice out to rush and go riding.