Right I've just checked the compression and the figures are 197psi, 222psi (middle), 215psi. There's no figures for this in the manual so I've worked on the 10% rule. 222 - 10% = 199.8 so one is a tiny bit under which to me is nothing and could be down to the small gap between the increments on the clock (it goes up in fives) and I read them slightly out. I did this cold/dry as the bikes stripped for a full service and with the throttle wide open. The valve gaps are spot on (have'nt moved in 8000 miles :icon_biggrin:) but I've not done the throttle body's yet. Do you think that the low cyclinder could be down due to that t/b being slightly out and do you think these are ok? And Bixxer :bowdown I did use the search button :icon_lol:
your low cylinder at over 190 psi is fine .
you won't have compression troubles until you are well below 100psi .
the bike was setting for awhile so it's not uncommon to see the three readings be different .
if all 3 had a good coating of oil on the cylinders the readings probably would have been more equal
anything over 125 psi is generally accepted as ok .
the real test of compression is a leakdown test .
ie how long it can hold the psi from dropping.
the throttle bodies have nothing to do with the compression .
the valves won't cause low compression until you have one at zero clearance .
Whilst in the shower I had a light bulb moment and remembered that the t/b's are only relevent at tick over and I had the throttle wide open, deeerrrrr. I'm thinking that the results might be nearer if I did it warm due to expansion but the rings should expand by the same ammount surely. I know that these figures are fine I'm just curious now. I might do it again after I've set up the t/b's when its warm.
The TBs affect more than tickover because adjusting them moves the butterflys albeit only a small amount. If you have one lagging behind slightly it'll lag all the way to fully open and if bad enough won't be fully open when the other two are.
When done, tickover is smoother, but so is the full rev range.