Well I want to change the blog but I don't have too much to say, so by default it's bike news. I've got a new idea regarding the triumph & the spare motor I yanked the cams from. This is mostly just thinking so far & nobody on the triumph boards has tried this before. The thrux's motor is a larger bore than the spare bonnie motor, otherwise nearly identical. They both have the same compression ratio. IF they both have similar flat-top pistons built to the same deck hieght with head gaskets of the same thickness (I'd figure this at least as likely as not) the way triumph got the compression ratios the same would be to use larger combustion chambers on the thruxton. That means that swapping heads would get me more compression. I found from triumph parts microfishe that both heads use the same size valves, which is good. I can't find combustion chamber volumes anywhere. The head/base gasket sets are like $100 or something I think, which makes it no fun to pull both heads and find out the combustion chambers are the same. I still would like to build an all-out motor of course, but for chrissakes I really gotta stop somewhere. It's fun as hell as it is, you know. I'm really pleased with the cam improvement & it would give me some satisfaction to not spend much more but get the compression up where it aught to be, somewhere between 10 and 11:1. Of course I'd go ahead & get a 5 angle valve grind & some porting while it's off. The dealership I bought the bike from had an awesome mechanic who would've gladly got me an answer, but they closed shop a few moths ago.
Edit: I took a ride out to the new place that's carrying triumph & low & behold the same mechanic works there. He said the 865's pistons do have a slight dish while the 790's are flat. That's his guess as to where the extra area is rather than the combustion chambers. But he's going to have a head off a 790 tomorrow, he said he'd measure the chamber volume. Too bad it isn't an 865 he's measuring, I could just pull the head off the spare 790 & measure it & I'd have my answer.
Edit: I took a ride out to the new place that's carrying triumph & low & behold the same mechanic works there. He said the 865's pistons do have a slight dish while the 790's are flat. That's his guess as to where the extra area is rather than the combustion chambers. But he's going to have a head off a 790 tomorrow, he said he'd measure the chamber volume. Too bad it isn't an 865 he's measuring, I could just pull the head off the spare 790 & measure it & I'd have my answer.
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just for that, i'm putting my clothes back on.
sucka.