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low rpm shudder

2K views 5 replies 6 participants last post by  Razel 
#1 ·
I had 12k service complete on my '03 K1200Gt last spring. The bike now exhibits
what I call a "shudder" when climbing slight grades or under load at 2500-3500 rpm.
There seems to be a slight loss of power at low throttle low rpm operation. The
engine did not have "shudder" or low power problem before 12k service. Engine
also runs slightly higher than normal operating temperature now. The tech said
valve clearances were too loose and added shims under each bucket at 12k service.
I had a second shop check afterward and they reported clearances were within specs.
Has anyone else had a similar experience with loss of low rpm power?
 
#3 ·
I Shutter

Right on Brucecha, Gottta love the NGK's. Another thing you may try is fuel injector cleaner. I had a similar problem when I had a KLT and one tank of cleaner cleared it right up. I've been a user of fuel injector cleaner since 2000. My personal choice is Lucas Fuel Injector Cleaner. My theory is when you run for many miles and cover several States like you can here in western North Carolina, you can't always be loyal to on brand of fuel. So by constantly mixing fuel brands and all having different additives, weird little thingies grow on the injectors. Not a bad idea to run a bottle of Chevron Techron thru the system first, then start a regiment of Lucas cleaner. Techron was recommended to me by my dealer so it won't hurt anything, like the additives. Good Luck! :D
BTW- If you have Chevron stations around your parts, their premium fuel has Techron in it.
 
#4 ·
I, personally, would be worried if I had to have a reshim on an engine at 12000 miles. If valve clearances are out at that mileage it could have been carbon build up.
In any case, if it were my bike, I would first recalibrate the motronic injection, and if the problem persisted check the HT leads, plugs and because of the reshim, I would recommend a compression test too.

Just having plug gaps 50% too wide could ,alone, cause the symptoms..

Good luck anyway..
 
#5 ·
Make sure all your plug wires are snaped on the plugs.....pull your plastic wire and plug cover and give each a pull....should be a bitch to get the wires off the plugs...if the wires come off with ease then there not on all the way...should have a good snap when they are locked on...pull ypour cover at night and look for spark leaks in the dark....good luck
 
#6 ·
1 exhaust valve at the first 12k service needed a shim. I asked, but was told while unusual, not unexpected. I decided to wait-n-see.

1 exhaust valve at 36k, different one, but I don't recall exactly which one. That's been it for 100k...

I do know that the buzzines at 4.8k RPM went away after the 36k service, so while I can't prove it, I'm pretty certain the buzz can come with the valves in spec. If you do go for the fuel system cleaner routine, plan it such that you do it three tanks before the next oil change. I don't know exactly what the cleaner has in it, but have been advised that it's good practice to change the oil soon after the fuel system cleaner is used, and most bottles that you get at an auto supply store will treat a tankful on a car, which is about 3 for the K1200's.



 
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