ExtraRegularGuy
XS650 Enthusiast
Getting ready to hone my cylinders. Just wondering if anyone has made , seen, or used a torque plate for their cylinders?
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Torque plate
- Thread starter ExtraRegularGuy
- Start date
OK, I'll be the first to display my ignorance. WTF is a torque plate and how would it relate to cylinder honing?
ExtraRegularGuy
XS650 Enthusiast
Dont worry about it, at a point i had no idea wtf a torque plate was either. However, they are key to performance. A torque plate is used to simulate the load and distortion placed on the cylinders by the cylinder head. This ensures that the cylinders are straight and round once the cylinder head is fastened to the engine.
It's a plate used to bolt down cylinders to simulate the pressure they're under when assembled. I've heard of doing that for boring them but never heard it mentioned for just honing. With honing, you're basically just scuffing up the cylinder walls. I don't think you have to worry about using a torque plate for that.
Once upon a time, when 750 kits were produced with thin liners, some engine builders used torque plates on XS650 big bore jobs. That was then. This is now.
ExtraRegularGuy
XS650 Enthusiast
I've heard of it done while boring, but never have I seen it. But I guarantee any serious performance build has been torque plate honed
Thanks for the information guys,
but as it don't torque nothin' the name had me puzzled; it's surely a compression plate?
And don't you need two of them, top and bottom with correctly torqued studs & nuts between them to simulate how the barrels are held in the engine?
but as it don't torque nothin' the name had me puzzled; it's surely a compression plate?
And don't you need two of them, top and bottom with correctly torqued studs & nuts between them to simulate how the barrels are held in the engine?
ERG, exactly how many XS650 performance builds have you done?
ExtraRegularGuy
XS650 Enthusiast
Well, I'm pretty new to performance industry. But I have been involed in a couple, I go to a school that specializes in building too notch engines. So I am just taking what I have learned from working around, and with some very great engine builders and applying them to my build.
ExtraRegularGuy
XS650 Enthusiast
Sorry, I misread. this will be my first XS650 build Griz. But I would imagine that round straight cylinders would be desired.
Huszarail
XS650 Enthusiast
A torque plate or honing plate simulates the distortion on the cylinder caused by tightening down the cylinder head, usually in automotive motorsport applications (moly faces rings are usually lapped 'light tight' in a ground finished tube at manufacture). An Small Block Chevy bore, for instance, will go slightly (very slightly) hexagonal when the head is tightened down. The honing plate simulates this load and distortion and allows the cylinder bore to be honed round for excellent ring sealing (allegedly). Just over-kill of street use and really not straight forward to do on an XS cylinder.
ERG, I take that to mean none. And that's enough for definitions and theory. If you want to know how to do performance work on the XS650 motor, don't confuse yourself and others. Buy a download of Craig Weeks' XS650 performance modification manual at 650performance.com. And take the trouble to talk to some people like Craig (he's here as "650performance"), Gary Hoos of Hoos Racing (he's here as "hooser"), Michael Morse of 650 Central, and other folks who've built/are building XS650 race motors before you start telling people what's done on these engines.
Hi grizld1,
yeah, those are the XS650 go-to guys for sure but be nice to the OP, eh?
What I read into this string is that ERG is questioning something that his Gurus have told him.
And that's a good thing.
Huszarail
XS650 Enthusiast
Someone's grumpy in the mornings eh?
ExtraRegularGuy
XS650 Enthusiast
So it seems that no one has seen a torque plate for an XS. Guess I'll have to make one, it'll be fun to measure the bores with and without the torque plate and see how much it distorts. I'm sure you are anxious to hear the results of the experiment griz
lighten up will you? Im just in the pursuit of horsepower
lighten up will you? Im just in the pursuit of horsepower
He's not questioning anything, Fred: "I guarantee any serious performance build has been torque plate honed." Engines differ on the amount of distortion caused by pressure applied to the head fasteners. Boring with a torque plate is considered best practice on older Harley motors (and that may be the case for newer ones, I don't know.) But these machines aren't Harleys. I'll shut up and let Craig and Gary carry the ball if they want to.
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ExtraRegularGuy
XS650 Enthusiast
Yup, I said that
Back in the day, our general rule-of-thumb was to use torque plates on cast iron cylinders that had threaded holes for headbolts. That pretty much covered Harleys, Triumphs, and certain golf carts. Torquing down the headbolts would slightly distort the region around the threads, which is fairly close to the cylinder bore at the critical top. Didn't use torque plates on aluminum block sleeved cylinders which used long studs. The clamping force on the cylinder in the boring bar simulated the assembled engine's clamping force.
But, that's all old-school '70s tech...
But, that's all old-school '70s tech...
Dave From Maine
XS650 Member
To me honeing is a Sears and Roebuck three stone hone chucked up in a cordless drill roughing up the walls, it could follow the inside of an eggshell
ExtraRegularGuy
XS650 Enthusiast
That is one way to go about it. but there are much more precise ways to hone out cylinders.
