Sunday, October 26, 2008

KLR 685 cylinder removal

Bike stripped down ready to drop the coolant and remove the carburetor. At this point it only took me around fifteen minuets..
I'm not going to bore you with a picture for every part I remove so we'll start it off with the head.. Plug looks very clean so I don't have the jetting too rich. Right now I have the dyno jet needle on the middle clip and a 153 main jet.

The top of the piston had a fair amount of carbon for only having sixty three hundred miles.
I'm not sure if this is due to running the bike on cheap gas or lugging the engine too much.
I was debating using the thinner base gasket to bump up compression but after seeing this I'm afraid of pre-ignition.

Cylinder looks normal for a big bore. The picture makes it look a little more dramatic, nothing you can feel.

The skirt looks really good and the rings were not that lined up when I pulled off the cylinder. The gaps were about eighty degrees apart. Cary from Schnitz said that the rings normal rotate and compression would still be good if they happened to line up. You figure piston ring end gap is only .018" so a line up wouldn't do much.
The weight of these pistons in your hands feels huge. Most likely all the weight saving is from the much shorter piston skirt.
This coming Saturday I'll drop off the cylinder and piston to get fitted. It's going to take a week to get back. While thats away the valves will have the clearances checked. That should be very easy off the bike and on the work bench.
So far total time is about two hours.

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