Rough idle (dies) when hot.

[kpchief]

I have had this issue since I got the 04 bulldog in april. The bike will idle fine when*it is first started up, it will accelerate and run just fine. After about 15 minutes into the ride it will have trouble idling. The lights on the tach will blink, only when it is idling, which is telling me low oil pressure. I have changed the oil and used a K&N 170 filter with Mobil1 20w 50 oil. I also cleaned the tappet screen when i changed the oil. I have cleaned the air filter with the K&N kit and re-oiled it. I have reset my carb to factory settings and adjusted it following the S&S guide. It will run fine but just has issues idling after it is warm, it will eventually die after idling rough for a minute or two. Any ideas on why it would be idling rough?*

I also have oil dripping from the crank case breather, behind the air filter. It sure makes a mess. Could this be part of the issue?

Sorry for the long post, and thanks for everything

 

[stlmikie]

When you get it hot and the idle slows turn that idle speed screw. If I'm not mistaken the flashing lights are cause of a low idle speed? When you say it dies. If you were to stay on the throttle would it still die? Without seeing it, it sounds as easy as a low idle speed. But it also sounds like it could be a crank/cam sensor.

 

[01Mastiff]

If you're getting oil out of the breather after changing oil it's because you put a little too much oil in. You should notice it stop after it reaches its correct level then you can see where it is on the dip stick and use that mark from then on. Manual calls for 3 quarts but if I use more than 2 3/4 quarts it will blow the rest of it all over engine, exhaust and my pants. Learned this over time. In the summer my engine would die at intersections when at idle. I ran a little "sea foam" in with the gas for about 5 fill ups and it cleared it right up. Don't know if it was coincidence or what but I also started running some through my hotrods and it seems to smooth them out at idle, but then again I'm old; deaf and can hardly see so who knows what the hell is going on.

 

[V]

When you get it hot and the idle slows turn that idle speed screw. If I'm not mistaken the flashing lights are cause of a low idle speed? When you say it dies. If you were to stay on the throttle would it still die? Without seeing it, it sounds as easy as a low idle speed. But it also sounds like it could be a crank/cam sensor.

The f;ashing lights as mike noted are to alert you to a "to low idle setting" min idle should be around 950 RPM's. I think thats when the lights start to flash. It also is to warn you that RPM's that low are not building enough oil pressure.

 

[ringo]

I rode with a small screwdriver in my pocket so I could adjust the idle speed at red lights until I got it right.
yep, lights flashing indicates low idle speed. try to get that second light to be flickering on and off when at idle

 

[kpchief]

Thanks for the ideas guys, I will try to dump some oil and see if that helps the leak from the breather. I did read about that but I thought I had the level right. As far as the idle issue, If I stay on the gas it will run fine. I will mess with the idle screw again. I will throw some seafoam in the next couple tanks to try that. Much appreciated.

 

[BadBrad]

Rocky's Mastiff does the same thing. Once hot, her idle decreases just enough to give her problems and occasionally die while stopped. Adjust your idle up a little. I know a lot of folks like that low idle sound, but it's not recommended for our dogs. Ride it till it's hot, adjust your idle until your lights stop flashing and you should be good to go.

 

[stlmikie]

Keep us informed too. Fixed or not.

 

[kpchief]

Yep, planned on updating the post after a poker run tomorrow. Took it for a quick spin after adjusting the idle the other day and emptying about 12oz. Of oil. I read on another post that there should only be about 2inches of oil in the oil tank, is that correct? The idle seemed fine, but still had oil coming out from the breather. I will let you know more after tomorrow, thanks guys.

 

[Dezertrider37v]

Your engine is nice and tight when it's cold, if you find your oil and idle settings are good then it's time to check the compression. When your motor is blowing oil out of the vent that's blow by. In my experience engines that are harder to start when warm or have trouble idling warm but act fine when cold are suffering from low compression from worn rings.

I'm not saying this is what's wrong with yours but those are a few of the symptoms you would experience.

 

[kpchief]

Craig, i am still learning this bike where are the rings that you mentioned?

Thanks

 

[Dezertrider37v]

Sorry for not being specific, I was referring to the piston rings. In most cases the rough idle could just be jertting, plugs, idle mixture, intake leak. But when you mentioned the blow by that made me lean to the compression side of things. If your compression is good then I would turn my attention to the carb.

 

[kpchief]

Well, made it through the ride and the leak wasn't as bad but still had a little bit on the inside of the air cover. The idle also seemed to be better after adjusting the idle screw in more. But now I need to replace my fuel line because it melted to the crankcase. I will see if I can test the compression on both crankcases and see if the piston rings may be an issue. Keep you posted.


thanks

 

[Th3InfamousI]

Well, made it through the ride and the leak wasn't as bad but still had a little bit on the inside of the air cover. The idle also seemed to be better after adjusting the idle screw in more. But now I need to replace my fuel line because it melted to the crankcase. I will see if I can test the compression on both crankcases and see if the piston rings may be an issue. Keep you posted.


thanks

Fuel Line melted to the crankcase? How does that happen?

I assume you have the stock Air Cleaner? On the 04 you will get a little oil blow by from the crankcase which blows into the air cleaner that is normal operation on these 04. It shouldn't be leaking down your engine much at all but a little oil blow is normal. They moved to a different engine breathing system in 05 and that greatly reduced the amount of oil blow by.

 

[kpchief]

I was a little suprised too but it is only a rubber hose. Oh well, now I have a good excuse to put a steel braided fuel line on. Yes it is the stock breather, for a little while longer till I get the money to upgrade it. As for the leak from the Breather, I think I will be putting the wimmer breathers on this winter and at least catch the oil. Thanks again everyone.