FMF Gold Fatty's to Pro Circuit's?

[phillybuilt]

Hey everyone, I did a lot of research before and I want to make sure what I read was correct. For whatever reason, I couldn't make an account until today, I've owned this banshee for about a month and have straightened a bunch of things out so far, and now I feel comfortable with starting to modify it. Still learning about everything but just wanted to get some opinions on my setup, since I got an offer on a set of Pro Circuit's that is truly too good to pass up. Current setup:

 

Stock Cylinder/No Porting/Stock Carbs/TORS Delete

FMF Fatty's

Pro Design Cool Head - 21cc Domes

Ditched Boost Bottle for Stock Crossover

340 Main, 30 Pilot, middle clip (Vito's needle) and 1.25 turns on the screw

Pro Flow filter adapter with K&N, no airbox lid

32:1 Castor 927 & Sunoco 93

NGK BR8ES (.028 gap)

130 Compression, ZERO air leaks!

 

When I got it, there were air leaks everywhere, had the dreaded TORS, was overheating from wrong jetting, had a boost bottle, head looked like it was resurfaced with a belt sander, it just had tons of issues that seemingly never ended. I fixed all of that and it seems to feel really good right now with the above setup. It's currently between 40 - 50 when I'm riding, and I'm anywhere from almost sea level to 700 feet tops. Starts first kick, feels pretty good, runs and idles fairly clean. Waiting to take it to a wide open area for a plug chop before I begin riding it full time, but based on what I've read and how it felt the couple times I've rode it (versus what it was before) seems pretty close.

 

Now, I've read of some people with similar mods that are using a 27.5 pilot and a slightly smaller main with Pro Circuit pipes. Basically looking for someone (if anyone) who went from FMF's to Pro Circuit's, and if you're using similar modifications, what should I begin with for jets? I have enough mains to go fine tune down from 340's, but I'm curious if I should get a pair of 27.5's before I decide to get the Pro Circuit pipes. And also, if I run the UNI pod filters on the carbs, should I step up to say a 360 or higher? Those will be used in 60 - 80 degree weather during the dry summer months.

 

Sorry for the long winded post, thank you for your advice!

Edited November 26, 2016 by phillybuilt

[JTmachining]

Why change pipes

[phillybuilt]

FMF's are just beat up, tips scraped, painted black very poorly, they just look terrible. I'd like my machine to look and run nice. And for how cheap I could get the Pro Circuit's, I could probably sell my FMF's cheap and pay for the Pro Circuits. I have also read that the Pro Circuit's are a much better pipe. Just a personal preference really.

[camp0429]

You should be way rich with those mains and no porting

[sleeper06]

They jet very close if not same. You gave the motor a pressure test ? I'm in Long Island and in the northeast I see more bikes needing 30s for pilots . As long as it's mechanically sound you should be 280 -290 main 30 pilot and get toomey needles , Vito's needle are terrible

[phillybuilt]

They jet very close if not same. You gave the motor a pressure test ? I'm in Long Island and in the northeast I see more bikes needing 30s for pilots . As long as it's mechanically sound you should be 280 -290 main 30 pilot and get toomey needles , Vito's needle are terrible

 

 

Thanks for the reply, sleeper! As stated, this is my first banshee, and it may have been a running and riding bike but it has been quite a project so far. Before I did anything, I addressed the problems I had first. Wrong jetting (partly causing overheating) and air leaks. It holds 6 psi (now) on air leak test and has 130 psi on both sides for compression. The cylinders and piston tops looked gorgeous when I had installed the Pro Design cool head. Previous owner said it was rebuilt recently, but had no documentation. The cylinder head looked like someone had decked it with a belt sander and that could have also been contributing to the overheating, as well as the wrong jetting. Luckily, the cylinder surfaces polished out perfectly with a little prep work and patience.

 

With 30 pilots, middle clip on the Vito's needles, 1.25 turns out on air screws, and 340's it runs beautiful. Starts first kick, idles clean with little smoke, response is crisp, difficult to keep the front end down... Plan to plug chop it this weekend when I can get out to the place we ride. I really appreciate your feedback being so close in elevation and location, and I have a couple questions for you... Why should I switch the Vito's needles? And should I wait until changing the pipes or do it now? Also, is that jetting what I should be running with no airbox lid and the K&N cone filter? And in the summer time when I run pods on the carbs, how should I alter my jetting? Thank you in advance!