Well ****.. I haven't messed with sprocket changes since bmx days and I guess I remembered backwards... I'm going to stick with the 30t for now. The 70t rear won't be here in time to PC with this batch so maybe I'll stick with the 66t rear for break in and see how it feels. Could still try the 70t later and switch it back if I don't like it. She might wheelie with no clutch lol. Learn something everyday haha

 

I did the 30T first, bought a 70T rear and never put it on. I just like the 30/66 too much to mess with it. What I liked most about the change is it revs faster. I think more of the engine torque makes it to the rear wheel as well when I was reading up on gearing formulas.

 

I love this thread :-)

I'm working on a 117" build now.

As of right now, Wolfgang Grasser in Baytown, TX has done a set of heads for me.

Now I'm saving for a S&S 117 kit (new crankshaft, 117 cylinders & Pistons)...

Probably gonna keep my 777 cam, (but might go with a hi lift cam)...
And probably stick with stock throttle body (have Wolfgang Polish it a bit)....

Until I get parts, and have him assemble it - I'm living through your thread :-)

 

If you like you 30/66 you don't know what you are missing with the 30/70.....you will like it that much more.

 

If your going with the s&s crankshaft why not go 124"? Same price.. Don't get me wrong I'm not knocking your build at all. Just curious why? I was going to do the same thing, mainly because the 124" number kinda makes me nervous haha. I tried to let Kirby talk me into a 117" but in the end it's the same price for either crank. I'm going to be looking for your thread also where are you going to post it?

 

A lot later than I wish haha

Probably gonna be a year or more before I save up for parts and labor.

Dependability was why 117. NOT saying the 124 isn't, but Wolfgang said the stroke of the 117 was a tried and proven stroke. I didn't talk to him much about it to be honest. He suggested it over the 117 for long rides, and I said let's do it.

I also think I'll be plenty happy with the power. I'm ALMOST happy with my stock 103 with a 777 cam. I should be plenty happy with a 117 and head work.

But it'll be 6 months+ before I order parts. You have plenty of time to talk me into 124 haha

 

Haha no way man I don't know enough about it yet to start talking people into or out of anything. I asked Kirby about the longer stroke also but he said that you don't even start having issues til you get up to 4-3/4" stroke. But yea man I think you'll be plenty happy with the 117". Id say trust your motor guy and go with what he recommends. That's what I did

 

That is why I went with 113. If built right they will rev like a crotch rocket and when you hit it hits real quick in any gear.
i have around what you are looking at, 124hp/148tq.
I eat rear tires, 2 to 3 sets a year. What I like is cruising at 60mph and all you have to do to pass is roll on some throttle. want to pass real fast gear down to 5th, if that isn't fast enough go to 4th and hold on.

Personally I think you will have better times @ the strip with the factory gearing.

You will have all the low end you want, and then some.

 

Damn dirt bobber 148tq is an insane number. Man I would love to take'er out to show me a good time!

 

All of the sudden, I feel like I got a 2" ****.