Thinking on a new pipe, been occasionally dragging my VH 2-1 shorty comp. D&D has always done well power wise on the dyno, I’ve never had one so no experience. They do look a bit higher around the foot peg area where I scrape.

This is the fat cat -

The “borezilla” looks to be the same height with 17/8 primary tubes. The bike in play has a 107 zippers muscle kit, with decent head flow. Tuning has the Ci in the DJ PV at 124 and she runs tight. Never seen a dyno but easily gaps my buddies S1 FXDLS.

I’m thinking I ought to stay with the 1 3/4 primaries but not sure. Don’t won’t to kill the 2.3k pull or have to add washers - torque inserts or baffles. Then I think the next build will have the cases bored and a 117 added.

Looking to see if my pipe height estimate is correct from the pics and if the 17/8 will kill the low end? The low end is subjective and each bike is different, mainly curious to see if someone added the big primary’s and was disappointed.

 

You need to list ALL engine mods and didn't you raise the rear with 13" shocks?

In this thread you posted today about your Air cleaner upgrade, what is the pipe on that bike? can you post a better pick of the whole exhaust?

 

Unless you have a really high output 107" Twin Cam, I would use the Fatcat. I own a Fatcat and a Boarzilla, the Fatcat is on a 96" with cams. The Boarzille is on a 124" Twin Cam. On a smaller motor the Boarzille will probably as you mentioned loose low end, and most likely feel soft the entire RPM range. If you're sure you will be making the motor 117" soon, then maybe you can live with Boarzilla until you are ready for the 117".

 

Almost this . I'd stay with the fatcat.

 

Absolutely stay with the fat cat, 1 and 3/4 that steps to 1 and 7/8 within 6-8" is more than enough pipe then even my 110 would put out..

​​​​​​The Borzilla is made for big breeding engines...

 

I hope that’s a typo…..mine don’t seem interested in each other that way

 

Very cool, thank y’all.

That’s what I was thinking.

Bike is a 107 zipper muscle with the smaller 576 cam. HPI 55 and 5.3 inj. Super pleased how it runs, smooth from 2.3k and rips up top. Thought about a dyno session, but then realize the bike runs okay and those dollars could buy new Shinkos for the sporty.

Really, the big cases and 117-120ci is a pipe dream…


The scrape isn't too bad but man it makes me pucker.