Well new to the forum have read a ton of post and found a lot of great info on here, so i decided to sign up and post a question of my own.

Have a 99 rk fat cat 2-1, big sucker, and pp3 going to do a build this winter and have been quoted (for parts) two diff ways.

One: do a 98" cyl\pistons heads raised and ported, set up for a wood tw-8 cam with hyd roller conversion, comp releases and comp set to 10.8:1 per bob wood. Adjustable pushrods and new lifters. Maybe a speed perfrormance 48mm T/B not sure if its needed.

Two: S&S 106" crank, S&S cyl\pistons, set at 10.1:1, S&S roller rockers, adjustable pushrod, fueling lifters, vlv springs for the higher lift cam, other than the valve springs stock heads, andrews gear conversion, and 67g cams. no T/B at first (money) going with the same size bore as there will be no case modification needed.

Ok guys whats your thoughts. I ride two-up some times but also a lot of solo bar hoppin too....

 

98"; Woods cams can be noisy; aggressive ramps. Don't know if the 8 is noisy or not, just something to think about.

If you want to spend the buck for more displacement, you might as well case bore and jump to 117". Just don't see the added value in the cost of the 106". Heads should be ported and crank should be trued, balanced and welded. You are talking big bucks.

The 98" will be a good runner and much cheaper; JMHO.

 

the 98 will be the best bang for $$$ spent--also need to think about a upgrade to the clutch AIM makes some nice products -- the VPC T92, I have had 4 motor builds 3 HQs (two 107s, 103) and monster overkill 131 (stays in the shop)-- if you are going to ride the bike a lot a 98 from GMR, HQs, TMan or S&S will be proven reliable performance--OR a S&S 111 Crate Motor that could be had for about $5200 with a three year warranty

 

What's your thought on the t/b issue. Stock be ok with a 98" build or spend the extra for a 48mm.

 

Do the 98"
Tone the compression back a tad so that hot weather, bad gas are tolerable. Add compression releases
It will run well with the right headwork
Wood 8 can be tamed but won't be stock quiet
The right exhaust and the TB upped to a 51mm will pay dividends in hp.

 

ide either stroke it & go bigger than 106",or just stay with 95".i know we`re going against the grain,but we`re not sold at all on the 3.935 bore with HD cylinders.weve done alot of 95"ers,10.5-1,S&S 625G cams & our heads,very powerfull,easy to tune,ride anywhere build

 

Devils advocate here but there are several 98's (as well as 96-107's) over 100/100 running around our area.

I've not seen or heard (personally or FWIW internet forums) of a single issue due to the extra bore.

Kirby, have you personally seen a problem with this?

BTW 8 cu more is always better. It's only $$$

 

The 2 pc Delphi bored from 41-46.5mm(we manufacture our own throttle plates) is a great set-up.
That 98"er your talking about, is the most cost-effective way to a LARGE power increase. Absolutely nothing wrong with those whatsoever.
That was the engine size that was used here, for the build in American Iron Magazine.
IF, you plan on splitting the cases, with a flywheel replacement, then for the cost of boring the cases, and an Axtell 4.125", cylinder set, you can have a 117", 120", or even a 124".
Scott

 

havnt seen probs,but have heard of a couple.lets see a year or two down the road.just because it "works",dosnt mean its the right thing to do,check with S&S,they dont recomend it either(i woudlnt bore a evo .060 for a couple extra inches either)

 

I have a hillside 98 build with stage 3 hds 8g cam stock throttle body and se 16ga double barrels running 113tq 115hp big difference from my 95 with se251 and stock heads 90 tq 92hp.