Considering Stroker Crank

[vafatboy]

This winter I'm considering some S&S wheels to get me to 103.

Current stats
95 flat tops
37b cam
Big Boyz Heads
D&D FatCat

My crank run out is .004. I'm going to get the timken and a straight crank.

The questions are. Heads have stock valve sizes, do I need something different? Cam change would be in order. Woods?? Change from flat tops and bump compression?

[dzlfitr]

What is the compression now, and what are the Tq. and Hp. #s ???

[vafatboy]

Originally Posted by dzlfitr

What is the compression now, and what are the Tq. and Hp. #s ???

Compression was setup for 9.8-1 by Bean. Last dyno was 105 tq and 99 hp if IIIRC. That is 5th gear run SAE, but I think it's fudged by the tuner or high due to dyno calibrations. I have it running much better now with Twin Scan+ Wego and SERT. Just need to verify the #.

The question is what is a known performing combo for a stroker 103 without breaking the bank.

[Backroad Mike]

Warren;

Have you decided what your limit for breaking the bank is?

Once you start splitting the cases for the timken and new flywheel there are other costs too. Doing the work yourself, or having some else split the case ?
If doing it yourself, do you have or can you borrow the tools you'll need to properly set up the bottom end ? Changing cams ? Bigger valves ? Stage II port job maybe ? Any needed clutch work? Balance and plug the new crank ?
Bigger throttle body ? It starts to add up real quick.

And don't forget shipping. Thats a couple hundred extra.

[route66paul]

If you are going that far, why don't you go to a 117, 120, or 124? splitting the cases, you might as well bore them also and go with large barrels. You can make a somewhat tame large engine. It will run with stock ecm and stock heads, but a good set of heads with some 1.90 or better yet, 2.02 intake valves would be great. You can go with large ports and use a large intake ecm, or just a larger carb.

You don't have to have a high lift cam, changes to the valve train, or high compression, but they help. just haveing the extra inches will do a lot.

[Berserker]

What do you want out of the bike? As for going big engine, what else would need to be updated? Axle, chain? Clutch? I dunno, but when you get into monseter builds in cars, bikes, ect, you start to chase the weak link. So need to decide on your goal for this bike.


Myself, I will probably go low compression next build. No worrys of gas or heat.

If I keep Ultra, I will probably face this. I will do timken conversion, and S&S crank?? Maybe just bore the jugs to 103".

Now my FLHR which has 56k, someday will get opened up. I may go bigger then 103". But not alot. I don't want to be chasing things.

[vafatboy]

My point is I already have heads ported by Bean, if I need bigger valves, then I'll have him do it. I'm going in to do the timken anyway.........might as well get the stroker crank instead of having mine fixed.

I guess I'll take what I can get with 8 extra cubes, bigger valves if needed and cam to match.

Never mind, I'll call Bean

[Berserker]

Sorry I thought we were juast talking about bikes. Excuse **** out of me.

But I agree call the pro.

[route66paul]

Originally Posted by vafatboy

My point is I already have heads ported by Bean, if I need bigger valves, then I'll have him do it. I'm going in to do the timken anyway.........might as well get the stroker crank instead of having mine fixed.

I guess I'll take what I can get with 8 extra cubes, bigger valves if needed and cam to match.

Never mind, I'll call Bean

The point about going larger(117,120,124) is that the case boring and the cylinders would be your only real additions to the build, you will need pistons, rods?, and a cam anyway, also at least a hone on the cylinders(bore oversized is better), so why not go large while you have it apart?

[JDsCycleWorks]

As long as you have the larger valves in your heads,the 4.375 stroke crank will work great with your parts. I recommend the S&S crank set. It is a strong reliable part. Be sure to check the cc's of your heads and do the math for your compression ratio because the longer stroke will raise your compression.

[Thorns]

Warren, you buying a stock bagger bike to take trips on?

Thorns

[pa-glazier]

Originally Posted by vafatboy

My point is I already have heads ported by Bean, if I need bigger valves, then I'll have him do it. I'm going in to do the timken anyway.........might as well get the stroker crank instead of having mine fixed.

I guess I'll take what I can get with 8 extra cubes, bigger valves if needed and cam to match.

Never mind, I'll call Bean

It might be a good idea to talk to Dark Horse - Hoban Bros . They specialize in crankshaft work and could probably offer some good advise.

[vafatboy]

Originally Posted by JDsCycleWorks

As long as you have the larger valves in your heads,the 4.375 stroke crank will work great with your parts. I recommend the S&S crank set. It is a strong reliable part. Be sure to check the cc's of your heads and do the math for your compression ratio because the longer stroke will raise your compression.

Thanks Dave!

Originally Posted by Thorns

Warren, you buying a stock bagger bike to take trips on?

Thorns

What?

Originally Posted by pa-glazier

It might be a good idea to talk to Dark Horse - Hoban Bros . They specialize in crankshaft work and could probably offer some good advise.

I've will talk to them before I do anything.

Thanks,

[TerryMiller]

As mentioned earlier the heads are going to have to be reworked because the compression's going way up with the addition of the extra cubes.

Adding 41/8" bore pistons and boring the cases don't add that much to the cost if you're already in the bottom end.

There's a new Timken conversion kit that makes it pretty easy on any knowledgeable engine builder. I guess it's a lot of steps, but the critical case machining goes away and they're left with just drilling oil passages and other non-critical stuff.


Good luck with the build.

[TXCHOP]

Well here is another couple things to consider.

Camplate and oil pump. While .004 isn't really that bad a runout with chain drive cams, it can chew up the camplate and oil pump. It will add to the budget if they need to be replaced.

A 103 crank will drop right in with the new correct pistons and a bore(hone). Timken is not critical, but very preferred. You can buy dished pistons(as you have to buy to stay with your 37b cam setup). Cc'ing the heads and installing a 1.9 intake is something Bean doesn now and would work at a minimum. That would be a nice. build with a little gainover what you have now.

For a bit more kick, a Wood's tw6, flattops, and proper heawork to match.
10.2 compression recomended.

You can go up from there as you have a relatively light bike(for a harley) and step up into more cam and compression, but rockers, springs and other stuff is extra...

Just my .02