Spark plug gap

[Guest]

Just installed new HD valve springs on my 83 GS1100E for my web 168 camshaft I putting new spark plugs. What should I gap the plug at.

[Steve]

The stock gap is 0.6-0.7mm, or 0.024-0.028".

Probably no reason why that won't work for your bike.

.

[chedd]

yep ,i allways gap my plugs at 25thou,just 'cos it's easy to remember.

[enelson2047]

Spark plugs

Thanks for the update but now my intake cam broke in half when I was tighting down. What happen?????????????

[Nessism]

Sucks man. Sorry.

[mrbill5491]

Thanks for the update but now my intake cam broke in half when I was tighting down. What happen?????????????

Apparently the cam must of had a fracture in it? Lucky it broke now then at 8,000 rpm.

[2BRacing]

Thanks for the update but now my intake cam broke in half when I was tighting down. What happen?????????????

Did you tighten the caps bit-by-bit in the correct sequence? Some of the cam lobes will be pointing down onto the valves, and with your new HD valve springs, this causes great resistance. Tightening the cam down too much at a time on one side against this "resistance" or in the wrong sequence can cause the cam to "bend" and break.

[Nessism]

Service manual for the 8V engines calls for clamping the cam down into the head using vice grips before the caps are installed. This reduces stress on the cap hold down bolt threads and assures there isn't any physical blockage, such between the valves and pistons, before you bolt down the caps. My guess is as Steve suggests: maybe the cam timing is off and the valves were hitting the pistons. In addition to your broken cam you could have bent valves.

While you were tightening the cam bearing cap bolts, did the bolts tighten with low effort? Did the caps seat down easily or did you have to really torque the bolts? I'm surprised you didn't strip out the cap thread before the cam broke.