Never Happen Sorry

[John]

Originally posted by pgg
Yes Dan, I'm everyones worst aggravating nightmare - a ranting raving irish kiwi. Ha Ha. Thanks for your good knowledgable info. Very interesting. Well, my XS has been tweaked and prodded pretty much to the max and has oodles of grunt, so I don't really need to dial up the cams, but for sure it'd be a good trick to know. Cheers.

P.S. heres a pic of my mongrel. http://homepages.inspire.net.nz/~patrick/xs11.jpg

It looks pretty good, but is that a speck of dirt I see on those carbs, kiwi?

[pgg]

Very rare bikes down here nowadays Dan. Just to thrash the cam dialling subject a bit more, I read an article describing a different technique. The mechanic says he screws a very accurate compression gauge into a sparkplug hole then actually gets the whole engine spinning with an auxillary electric motor. He then gradually tweaks the cams in stages until he finds the highest p.s.i. reading, then locks the sprockets at that setting. As for you John! I knew you'd have to rub more salt in! You can rest easy now - the carbs are officially tr**ple cleaned!

[John]

Hey Patrick. Had to get that last jab in. The weather must getting pretty nice by now. Have you been riding much lately? Your bike looks pretty nice, by the way. Enjoy the riding season.

[pgg]

Yeah mate it's warming up good, starting to see a few more bikes on the road now. The big p*ss off now though is the price of god***med petrol - you couldn't send over a few container loads of cheap stuff could ya?

[Dan Hodges]

Originally posted by pgg
Very rare bikes down here nowadays Dan. Just to thrash the cam dialling subject a bit more, I read an article describing a different technique. The mechanic says he screws a very accurate compression gauge into a sparkplug hole then actually gets the whole engine spinning with an auxillary electric motor. He then gradually tweaks the cams in stages until he finds the highest p.s.i. reading, then locks the sprockets at that setting. As for you John! I knew you'd have to rub more salt in! You can rest easy now - the carbs are officially tr**ple cleaned!

You can spin a motor with an electric motor. Some people did that years ago on rebuilt engines and some race motors to seat the rings, check oil pressure and numerous other things. With modern rings and well finished cylinder walls it is no longer necessary. Getting the highest cylinder p.s.i. won't necessarily make the most horsepower. If that was the case, you would simply use the shortest duration cam you could find, because the earlier you close the intake valve the more pressure you will make. If you take two cams, one with 200 degrees of duration and one with 225 degrees of duration, all other factors being the same, the one with 225 degrees of duration will make less pressure due to the intake valve closing later in the cycle. Reher&Morrison Racing Engines in Arlington Texas has a set up they call a spintron and it will spin a 500 c.i. rat motor fully assembled with the valves adjusted to 9000 r.p.m. or more. They are checking for parisatic losses,oil system designs and lots of other things. I would suggest getting a cam catalog from Comp Cams, Crane or one of the other manufactures because they explain it a lot better than I ever could. I know one thing, I won't be asking David Reher if he used a electric motor to check the cylinder pressure in my 555 c.i. bullet when it's time to freshen it up.