I'd like to get my Banshee's head shaved Friday. Any suggestions on how much to shave off? I've been told 0.050 Anyone else done this? Thanks.

 

You are going to get a lot of info on this in the archives, but, I can save you the hassle.

After going through this last month, I asked a lot of people the same question. Forum participants, local atv shops, and companies like CT racing. I can tell you that if you do the same, you'll likely get numbers anywhere from 0.020" to 0.125". What I found is this:

You need to target fuel type first. If you are planning on running 92 octane, then most (reputable) people will tell you, don't go any lower than a 20 cc dome. In order to get this, you need to shave 0.040" off the stock head.

Why 20cc's? Well, according to Allen Knowles from CT - smaller dome sizes (with a stock motor + pipes) will actually make the bike SLOWER!!! Smaller domes does NOT equal more power in this case. The chamber volume and porting need to be matched or the motor will make less peak power.

If you want to do additional motor work, then things are a bit different.

Personally, I listened to CT and I was not mislead or disappointed in the results. Power and throttle response were both increased a small amount - what do you expect for 50 bucks?? It is definitely worth it.

Be VERY aware of people that are telling you to shave more than 0.040". There is something called a squish band that will need to be modified if shaving beyond 0.040". Unless you're going to get a full head mod which recuts the domes for proper squish angle and clearance, just stay with 40 thousandths cut.

My motor doesn't overheat or detonate on 92 octane. It is now faster than my friends quad by about 1 quad length at olds hill in glamis (it used to be about 1/2 quad length behind on the same hill). It has about 150 psi compression (sea level).

Here are some things I actually heard from some local phoenix shops that turned out to be BAD advice...

"Yeah, we normally shave 0.065" without cutting the domes" - shop #1 - (this would have stuffed my pistons into the head)

"If you cut 0.040", you'll need to run straight race fuel, I cut mine 10 thou and it made a HUGE difference" - shop #2 - (wrong! this guy was amazing)

"On my last (stock) motor, I ran 18cc domes (on pump gas), but I should have run 16's" - same guy - shop #2 - (turns out the guy is a moron - I heard this from TWO people at his shop - I won't go there again...)

I firmly believe that unless you get advice from companies that are very well known (not some bonehead at a local atv shop), you'll be wasting your time and money, not to mention making your quad slower...

 

The guys at TEAM ALBA are very knowledgible about this also (I talked to them about the Banshee which I had). I believe their site is www.teamalba.com. You should be able to get their # there.

 

Cool. Thanks for the replies. Can anyone tell me what to torque the head down to when I put it back together?

 

sandmanblue:

I've been kicking this same thing around for a while. Did you have to re-jet after shaving the head? If so what did you change from & to?

Rude Dog

 

answer #1 is 18 - 21 ft-lbs

answer #2 is - no. I didn't rejet. Keep in mind that I typically run my motors on the rich side, especially for the dunes. After shaving the head,
I ran the same jetting and didn't notice a need for a change. Right now I run 320 mains, stock pilots and needles in groove #4 (one groove
richer than stock), air screws 1 3/4 turns out. All this is for 300 to 1200 feet elevation and 50 to 90 degrees F. No air box lid, foam pro flow filter, boyesen reeds in stock cages and T-5's. 927 castor at 32:1 and 92 octane pump gas.

It definitely runs sweet. Bad news is, my friends 97 runs a bit faster with his new sst pipes... dang it! Time for more mods...

 

Well, the results are in. Today I picked my head up from the shop. I had it shaved 0.040 and also bought a K&N air filter. I put it back together and it made an incredible difference. Top end feels the same, but bottom end and mid-range are much improved. The machine revs up much quicker. I didn't rejet; I use 220 mains and run 93 octane with Honda HP-2 oil at 32:1. I rode it for about 20 minutes and checked the plugs. Doesn't seem to be running too lean. I don't know if it was the head-shaving or the filter that gave me more power since I installed them at the same time, but the two together made a dramatic difference. At $48 for the shaved head (including the gasket) and $40 for the filter, it was definitely worth it. I don't know if there is any way to get more bang for the buck. Thanks everyone for the advice.

 

I just had mt top-end rebuit with Weisco Pro-lite piston kit, had my head milled 30 thou and some mild porting done. With the combo of my T-5's my bike is a screamer. My brother's bike and mine used to be pretty even running up the hills in the dunes, now I am hammering him by 3-4 bike lengths.
Best money I ever spent on my bike!

 

glad we could help!!!