Stroker crank?

[mountainmotor]

(Professor @ Nov. 14 2006,12:21) My bad, I guess I confused myself.  

 Thanks for setting it straight.

After posting I did a little googling so to find a link to post that would better help describe influences/effects on cam timing , rod ratios ect .
There were many but this one is fairly complete and from a very reliable source ... for those thats interested it's a good read .


http://www.stahlheaders.com/Lit_Rod%20Length.htm

 

[DonnieF]

Mountain
I wasnt confused but thanks for trying to help , if you read my post closely you will see where i was talking about a stroker crank and a different piston with wrist pin centers moved which infact will increase piston dwell ever so slightly due to the rod angulairty of the extra stroke. Now if you go with a shorter rod you absolutley can decrease piston dwell when you change rod to stroke ratio.

If your screenname means what i think it does , What size and was it actually built by Sonny Leonard or yourself?

 

[DonnieF]

(mountainmotor @ Nov. 14 2006,07:46)

(mountainmotor @ Nov. 14 2006,11:18) Using the 2.5 mm stroker rods will decrease the numerical rod ratio even more
I needed to fix this because I left a key word out
" shorter " .

The 2.5 mm rods are 2.5mm ".100" shorter than stock stock rod length .

You posted this as i was writing my last post , with that said , then we are on the same page.

 

[Professor]

All other things being equal, wouldn't an engine still see more piston dwell time with a longer stroke? Say there was room to move the pin in the piston......

 

[DonnieF]

Professor
Yes with the key words in that sentence being "All other things being equal". I think mountain motor was thinking along the lines of a stroker "KIT" , kit meaning rods are included wrist pin stays the same and they take the length out of the rod. There are more then 1 way to skin a cat. With todays sleeves , many different rod lengths , custom pistons made to what you want and stroker cranks ... anything is possible as far as cid is concerned. When we first got on the subject the original poster asked if he could change the crank and leave everything else stock , i just assumed he wanted to change as little as possible. So came to the conclusion of pistons and crank and i was thinking along those lines. Sorry for the confusion.

 

[mountainmotor]

(Professor @ Nov. 14 2006,14:44) All other things being equal, wouldn't an engine still see more piston dwell time with a longer stroke?  Say there was room to move the pin in the piston......

" If " you moved the pin hole location lower , the only things you would accomplish would be to increase compression and ...... literally moving the piston top higher in the engine @ TDC than a piston with stock pin location . One look at a stock Busa piston and you would readily see why the pin cannot be moved to any real beneficial length without taking the oil ring out .

Remember , stroke is the distance the piston travels and bore is the diameter of the cylinder . If you change the pin bore location, the piston travels the exact same distance ... all else equal . Only rod length changes will effect dwell time shorter or longer...all else equal .


Nope Donnie ,

I was not speaking of any " kit " . There are many ways to get the job done when stroking the *Busa* engine and these include different thickness baseplates for use under the cylinder block all the way to different style and longer cam chain .... builders choice with it all .

Ya'll have fun with it  

Mountainmotor , over and out  

 

* the topic *

 

[DonnieF]

As i stated from my first post , i am no busa engine professional ...none of my dial indicators , calipers or micro meters measure in mm's LOL.

Does anyone have a picture of a Hayabusa piston? I would like to see the ringlands if you do.

 

[Professor]

There is one on page 3-61 of the service manual.

I think what you are looking for is where the pin is at in relationship to the oil ring. It almost is touching it. The land is about .079 wide (My tools and I don't do metric values well either).

Is this what you had in mind?



This is the reason I stick with pre tested configurations of other peoples design. There is not enough "engineer" in my brain!

 

[IFLYLOW]

(IFLYLOW @ Nov. 13 2006,23:09) Donnie, where in AL are you located? You have a shop? I'm interested in a big bore kit, how streetable is a stroker kit? Can it be riden on minimum 100 miles summer trips? Would the cams need changing? What do you recommend for a reliable 80% street/20%strip motor?

+1

 

[twowheelwerkz]

if you are looking for 200 hp you dont need to stroke or bore anything, you can achive this by rasing comp. (your choice ) valve job, portwork, and cams

 

[DonnieF]

Yes professor thats what i was looking for ... and as mountain said there isnt much to play with even with a metric ring pack.

 

[Professor]

Here is the Busa one from the Manual

 

[DonnieF]

Now there is a little more room to work on that picture.

 

[badassblackbusa]

just get one of bob carpenters kits and be done with it. any power level you want. from 200 to 300 all motor.

 

[Big Red]

I think you could build a reliable bored and stroked motor for every day use if you keep the compression and cam timing moderate.

 

[gnd111]

Get a stroker kit from APE with a spacer plate. No need for rods or pistons if you want a stock bore...

 

[Jay]

On a 5 mill stroker, you can compensate for the increased piston travel two ways. 2.5 mill spacer under the cylinder, or 2.5mill shorter rods. We have both options in stock.

On the larger strokes, 6 1/4 being the most popular because that is the limit of the stock cam chain. On 8.5 and 10 mill cranks, you have to use our cam chain conversion kit with longer cam chain..

The shorter rod ratio means less dwell at TDC which allows for very aggressive cam timing.

Jay

 

[JW OLDBUSA]

I've had one of APE's finest 5mm strokers waiting to go into my 1363 since last year. I keep looking for re-assurance that a stroker with mild compression and cam timing will last for a durable street rider and even long trips. I still haven't found many. I'm not installing it for a few months.

 

[GoldenChild]

I honestly wouldn't run a big stroker crank on the street myself...especially not long road trips.