bored cylinders

[Buffo]

does anyone know how much you can bore a 1982 vision cylinder?

have any of you folks had it done?

i dont want it bored so much that it becomes fragile.

i'm going to have the heads ported and polished as well.

Don

[jasonm.]

I believe the first oversize is .25mm over 2nd is .5mm, 3rd is .75mm over and then 4th over is 1mm over stock. Max. safe I do not know.

[silicon_toad2000]

they're aluminium blocks, so provided you can find a sleeve to suit/safely fit, you can go as big as you want. Just got to find the sleeves.

[Walt_M.]

I hadn't thought about changing the cylinder liners but, you're right, if you aren't concerned about the liners, you could go pretty big. Now I know how they made the 750 Vision motors!
(By the way, if your cylinders are really bored, perhaps you could tell them a story or get them a tv)

[Superfly]

where might one get a sleeve & matching piston at?

[Buffo]

i'm going to talk to some bike and auto speed shops. maybe combined i can find a new sleeve set.

is the yics camber designed to only hold the amount of fuel/air mix that is put into it by the current displacement?
does the 750 vision have a bigger yics box?
i wonder what the equation was thaty they used to find the right size for it. too small would hinder preformance and to big and the vacume wouldnt work right.  i think

Don

[Blake]

Also another thing you have to concider is that our bikes are water cooled, and so it makes the oversizing task even harder (cant go past water sleeves, inputs and output pipes, etc).


Also, the 750 DEFINATELY had a stroke job too. THATS an expensive task. but hey.  I say go for it.  And put me down for a bore and a stroke (no dirty pun intended) :)


Blake

[EH]

I have tried to contact the man with the stroker with no luck. the man I did talk to who led me to him said they used Opel 4 cylinder rods in that engine. Maybe they are shorter than Vision rods and account for the displacement increase using the Yamaha liners. They also completely removed the counter balancer assembly. That particular bike never raced due to difficulty finding a front damper that would work in extension as opposed to compression. If this was just an exercise in fabrication I am impressed at the ability displayed.
 That water pump setup is something I am going to try. I will move the thermostat to the radiator intake to deal with the hottest coolant and make it use the radiator.
  I would love to know how to convert to chain final drive. Wouldn't it be great to slip that V-Twin into a wideline featherbed chassis from Unity Equipe with an upside down front end and fat tires?

[silicon_toad2000]

you should be able to find a machinist to make you up a set of sleeves, after all they're just a round lump of steel with a big arse hole in the middle. Get your pistons sorted and just get the sleeves machined to suit (if you need to that is).
Don't forget as the mass of your (oversize) pistons increases, your max revs will drop and also if you stroke it your piston speeds increase at and given rev, reducing your max revs.
Also as you increase the displacement of the engine you'll need to get rid of more heat so maybe factor in a new/recored radiator. or at least get the old/current unit rodded.

[FastForward]

Vision 750 Dirttracker...Chain drive