dropping in a stroker?

[ky 2stroker]

I was thinking about some things I could do to my R when ever the time comes that I have to do a topend or split the cases for some reason. I was considering when ever I need a new crank or anything that I was just gonna get a hot rods +4 stroker. A stroker cranks helps give more torque, right? and since I already have my cylinder ported, would a stroker work pretty good with the porting? and it said that I would have to have the head machined 2mm deeper to accept the longer stroke. could I just use some extra base and head gaskets instead of getting the head cut to get the same affect? or would it not be the same?

[flotek]

a ported stroker honda is a nice torquey bike ,lots of fun and fast accelration ,you should contact fiveonick considering hes the one who ported your cylinder,most likely though the porting will now need lowered with no spacer plate and the dome recessed to accomodate the longer stroke .

[fiveOnick]

The Blowdown will not be optimum after the stroke increase. It would probably run ok but I suspect it wouldnt rev too great.

[ky 2stroker]

I know I made this thread awhile back, but I was wondering how it all would work since I dont ever plan on getting a big bore cylinder. if I got a +4 stroker crank, how much displacement would I have? the bore and stroke would be 68mm x 76mm. and if I put in a stroker and got my cylinder ported again to match the longer stroke and everything and got the head cut for the longer stroke and still run about 200 psi compression, how much of an increase in power would I notice? and also maybe throw in the cr ignition system with it. would that be a pretty stout motor for the cc size?

[fiveOnick]

It could work it would put you around 192 exhaust 133 trans. I actually wouldnt go any higher on the ports just change some other things. I dont know how much of a seat of the pants change your really going to see though, not as much as a properly ported different cylinder.

[Quadracer351]

I ride a 89 250R but the crank and piston are out of an 86 which gives it about a 1/2 inch more stroke cheap easy to do and gives a gain

[fiveOnick]

Originally Posted by Quadracer351

I ride a 89 250R but the crank and piston are out of an 86 which gives it about a 1/2 inch more stroke cheap easy to do and gives a gain

Im afraid you are wrong, the 250R motor had a 72mm stroke in every single version of the liquid cooled motor. Even the 85 3wheelers were 72mm stroke same as the rest through 89. Rods changed in 87 but the crank was the same all years.

[Quadracer351]

if u look at a 86 and 89 piston side to side the hole where the wrist pin goes in sits higher on the 86 then it doe s on the 89 meaning the crank has to be longer. i jst destroyed the piston that was in my engine and had to replace it and get the cylinder resleved and after getting a 89 piston .20 over and puttin it in it came too far out of the cylinder so i had to call Wiseco up and read them the number that was on top of the piston that i removed and was then told that its an 86 .20 over piston i asked y it would be sitting diffrently and the guy said that the 86 crank that he put in there is longer then the orig 89. so thats what i was told and the 86 is sittin in there fine now. =/

[CR480R]

Originally Posted by Quadracer351

wrist pin goes in sits higher on the 86 then it doe s on the 89 meaning the crank has to be longer..

Or that the connecting rods are different lengths... which has no affect on stroke...

[ky 2stroker]

yep the connectiong rods are different lengths but thats it. and you could have used the first piston you had. all you would need is a spacer place. thats what I use.

my 86 motor has a later style long rod crank with a spacer plate beteen the cylinder and case and I run a 86 piston (86 cylinder aswell) cause there are alot more over bore sizes available.