Gen2 crank with 6mm stroke and 84mm pistons

[fzr1125]

With this type of motor should I be using all 6 gears through the 1/4 mile and do you shift a stroker at the end of the rpm range or at a lower rpm such as 10000 rpm. I have a hays 3 arm clutch bike is 70' I weigh 230 pds and it's a gen1 motor with gen2 crank with 6mm stroke and 84mm cp pistons. 1.37,3.63,5.53 @133.34 7.21, 8.66 @150.28 and I'm going through the traps in 5th gear. I also have a Shinko hookup should I change tire like people say I'm will not get any mph with that tire.

[STREETDRAG]

a big stroke motor like that shouldn't need to be turned to *******. Go out and practice to find sweet spot.. make pass shifting at 10k and go up 500 rpm increments till you see where it's going slower and back shift points to last mark it ran fastest... Also a good logger and doing some tuning couldn't hurt...

[smokinstorm]

Is there any possibility of putting it on a dyno to see the power curve? If your numbers are accurate, picking up only 17MPH out the end shows something went terribly wrong past the 1/8th. Looking at the power curve will tell you exactly where to shift it.

[sportbikeryder]

If it only went 150 out the back door after running 133 in teh 1/8th, I'd be checking the oil for gold...

Could be the clutches slipping up top as well, or it could be detonating once it gets warm in teh back half.

[BATTMAN]

With that combo, what size would that make the motor?

[STREETDRAG]

It depends if it's a 2mm with 6mm of stroke added equaling total 8mm crank or a 2mm with 4mm equaling total 6mm crank?

XR4 Register

With that combo, what size would that make the motor?

[BATTMAN]

It depends if it's a 2mm with 6mm of stroke added equaling total 8mm crank or a 2mm with 4mm equaling total 6mm crank?

XR4 Register

Using that calculator, what formula do you use to convert the stroke.

[Jay]

Using that calculator, what formula do you use to convert the stroke.

Not sure I understand the question. Want the formula for figuring out the displacement?

Stock gen 2 crank is 65mm. It would be a 71 if he stroked it 6mm. The motor would be a 1573

[STREETDRAG]

Just so you can play with calculator some here are some converted sizes, alot of folks round the number up:

Stock Crank Specs
Gen 1 = 63 mm
Gen 2 = 65 mm

Common Crank Up Sizes Are 2,3,4,5,6.25,8.5,9,10.5


Piston kits are usually:

81 mm -1298 cc
83 mm - 1363 cc
84 mm - 1397 cc
85 mm -1430 cc

Some folks round the numbers up


Fun to play with sizes,but your wallet never smiles

Using that calculator, what formula do you use to convert the stroke.

[BATTMAN]

thanks...thats the info I needed

[BATTMAN]

Not sure I understand the question. Want the formula for figuring out the displacement?

Stock gen 2 crank is 65mm. It would be a 71 if he stroked it 6mm. The motor would be a 1573

I was trying to figure out how many mm each crack size is?

[fzr1125]

The bike will be on a dyno this weekend and should I take that Shinko hookup tire off and put something else on there. I here there is a 10-12 hp drop with that tire.

[STREETDRAG]

find a good street tire.

The bike will be on a dyno this weekend and should I take that Shinko hookup tire off and put something else on there. I here there is a 10-12 hp drop with that tire.

[sportbikeryder]

The bike will be on a dyno this weekend and should I take that Shinko hookup tire off and put something else on there. I here there is a 10-12 hp drop with that tire.

You might want to pull the pan and look at the oil to see if a rod bearing is taking a shit before putting it on a dyno.

133 in the 1/8th and 150 out the back doesn't add up.

[fzr1125]

I checked the oil everything is ok