Forgot to mention, clean intake and tb, doesn't burn a drop of oil that I can tell, run oem filters.

 

What year is the smooth as silk 800? There were a lot of running changes in 2008, and major for 2009 and each year forward.

 

It's also 08, in fact it's 1 month older and has 5500 miles. Built August of 07.

 

You have covered all the basic stuff. I would turn the idle up to 1250 as described in your last paragraph and see what it does.


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Somethings to check. The boot from the throttle body to engine. Know to came loose. Check grounds. Also check the wire connector assemble going into the ECU. Behind the drivers seat. 2008 had a problem with the weight of the harness pulling down hard and making bad connections inside the connector. Can really effect the way it runs. Seems like all of my bad running problems where corrected when I pulled apart the connector and pull wires so they had slack. Figure out a way to take the weight of the harness of the connector.

 

Something else for the 08 was the fuel mixture system, EFI. It had several sensors and could take several starts before the system got it's final calibration. If one dies when first started cold and has to be restarted it was the EFI system making adjustments. Might trying to restart a couple of times when running rough cold and see if it smooths out.

 

Thanks for the tips. Intake boot is new, upgraded to the newer style with bellows and it's tight. That ecu connector is quite the mess but I've had it off several times now, even had it open last night finding the tps wires to test. Didn't notice anything loose but didn't really check them all either.

I have not done anything with the grounds, other than verify they were solid and not loose. Might be something to try. Didn't know about the restart trick.

 

The wires in the connector will not be loose. The wires are pulled very tight. Carefully pull slack in them toward the little connectors. I think with the wires get so tight they pull so hard it causes a bad connection. By pulling slack in the correct direction you take the stress of the little pins. Had several bad running and missing episodes that were fixed by doing the above. That was after I did all the usually checks like you have done.

 

I will try that.

 

So I took the grounds loose and cleaned them up good, also got some slack in the ecu connector wires and pushed them in , no change. So far nothing has made any difference good or bad. It idles fairly nice once it's warmed up at 1090, 1100 with a bit of variance and kind of lopes along. Tomorrow I plan to take the belt off and make sure I don't have something wrong in there.

 

Think you have a clutch problem that needs addressed then go back and adjust the tps for a 1250 idle.

 

Winner! Those of you who suggested this were spot on.

Actually first I adjusted idle to 1200, tps to .741. It seemed smoother there than any lower voltage. As I figured, the secondary was spinning at that speed. I could stop it with my foot, but it made the machine lurch when I put it in gear so that's no good.

I didn't know much about clutches so spent more time educating myself. First messed with alignment, thought I had it but no dice. Tried 2 spare belts, no help. Cleaned the primary bearing with brake cleaner, freed it up even better but no help. Finally I started it with no belt, and noticed it squeezed together just a tad. Luckily had the original weights given to me when I bought the machine and changed them out. All better now, secondary is stationary at idle.


We will see how it runs cold now, but I think it will be significantly better. At the least I got one problem solved. I can about see just how it got like it was, first owner changed weights for some reason, then had to lower the idle speed. And probably didn't know enough to adjust tps, that's why it was off the first time I checked it. The second owner who I bought it from (friend of mine) just didn't know any better, since like me, he had never been around any others and it ran great other than the idle.