R65LS Siebenrock Power upgrade to 860cc

[peter@inoxindustries.com]

Hello

I have installed a 860 upgrade (pistons and cylinder) to my 1982 R65 LS. Bike runs great but is showing lean. Any suggestions on Jet Sizes?

[schrader7032]

What are the current jet/carb settings? Is there a way you can test for wide open throttle response? In other words, do you have more throttle to turn but the bike won't go any faster? If so, then you need a bigger main jet.

But likely you might look at the needle jet and jet needle. The first thing you can do is move the needle up one notch. That's a big change but you can do incremental changes with the jet. Have you tried the "plug chop" test? Find a spot where you can pull off safely and check the plugs. Leading up to that, get the bike at a decent cruise speed say 60-65 mph and hold for a good two minutes. Then chop the throttle and kill the engine, and cruise into your safe spot. If you're lean at that point, then start working with the mid range settings.

[peter@inoxindustries.com]

Thanks Schrader
Just started snowing here so no test runs today. Also plot is thickening, carbs on bike are 64 32 325 not LS carbs which should be 64 32 335. Thinking of going up on idle jet ( to a 45 from a 40) first and main to 150 from a 145.

[schrader7032]

Not sure the carb number is all that important...it's the jets etc. that are important. Of course, you've increased the amount of air being pulled into the engine...could be that with not real changes to the carbs, there's less fuel provided to go with that air.

Typically, the idle circuit is only maximized in the first 25% of the throttle range as is the main jet being involved towards the end of the throttle range. It's easy enough I suppose to change some jets around and see what happens. Do let us know what you figure out.

[peter@inoxindustries.com]

Hello Kurt
Went one size up (45) on the idle and main (150) . Went out for test drive with my son on other R65 and LS seems to be OK. Had to cut ride short due to heavy rain and other R65 having issues ( new post to follow) . Seems bike is running cooler and plugs were starting to get some decent color.

Thanks

Pete