98 670 summit X mod suggestions

4

4pawdriven

Free Member

Aug 27, 2009

43

2

8

Laramie, WY

• Sep 7, 2009

• #1

I have a 98 670 summit x slightly modded interested in suggestions. I have CPI pipes, ufos, forged wiseco pistons + 1mm.

Anyone ever heard of polishing heads summitx heads are supposed to be really good factory heads. They are shaped like a trumpet's bell and have a rough cast surface in the combustion chamber.

Also thinking about getting a silver bottle, should I go boss noss or boondockers setup?

Thanks

 

A

ak

Well-known member

Dec 7, 2007

2,776

723

113

• Sep 7, 2009

• #2

Short rotary valve cover{pre mix only} and a 501 rotary valve. Gut the air box if it isn't already. Boondockers would be the better choice for a NOS setup,

 

winter brew

Premium Member

Lifetime Membership

Nov 26, 2007

10,016

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56

LakeTapps, Wa.

• Sep 7, 2009

• #3

For what type of riding? If you ride the hills the first thing I would do is a mild Drop/roll and go with a 2" track.....141, 144, 151, 156 or whatever fits your riding style. CLUTCHING there is some good gains to be had also. PM me you altitude and a little more info for a proven and CHEAP clutching setup.

 

T

Turbobusa

Member

Feb 10, 2008

196

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18

www.snowmobile-performanceparts.com

• Sep 7, 2009

• #4

Cpi Twins

I put some of those CPI twins on mine..and wow it woke up. Not sure I want more power, but if you come up with something that really works besides the pipes let me know. I am a mountain rider.
Thx

 

R

Racegun

Free Member

Jul 18, 2008

184

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Syracuse, Utah. Previous profile had 1,500+

• Sep 8, 2009

• #5

Turbo it!
I have most of the stuff you will need for it, you will just need to pick up a 53Aero.
PM me if you are interested, 8-10 lbs of boost works great on those motors.

 

4

4pawdriven

Free Member

Aug 27, 2009

43

2

8

Laramie, WY

• Sep 8, 2009

• #6

Mod suggestions

A turbo isn't really in the budget, the summit x comes stock with the 501 rotary valve. Does oil injection cost that much power? Do the rotary engines put up with the turbos well. Theres a guy in town (Laramie) who is selling one for 800 xp if anyone is interested.

All the performance heads I have ever seen are smooth as can be. How does the surface roughness affect combustion and ignition. I may ebay an extra set of 670x heads and have a machinist polish it and see what happens.

 

S

Skidoohmx

Member

Nov 26, 2007

154

7

18

Deary, Idaho

• Sep 12, 2009

• #7

Best bang for the buck if not already done is add a larger track and reclutch it. Are you sure your head does not have detonation damage. Show a picture if you can.

 

4

4pawdriven

Free Member

Aug 27, 2009

43

2

8

Laramie, WY

• Sep 12, 2009

• #8

No pic I don't have the head off currently. Its not detonation damage I have seen that before. Just the simple roughness of a cast iron pan. The sled runs good I just have some hp curiosity.

 

M

manowar

Free Member

Jun 15, 2009

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Marshfield, WI.

• Sep 12, 2009

• #9

the way i look at it the smooth polish heads vers as cast heads will make no real difrence in power or compatibility with turbos but in the event of mild detno it can work like a place to build heat faster and be more damage to parts.

 

M

manowar

Free Member

Jun 15, 2009

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Marshfield, WI.

• Sep 12, 2009

• #10

In basic terms smooth surfaces transfer heat mor evenly across the surface than a ruff surface .