70cc k-star kit

I.R.E. Mike Pee /
mijunkin
Dec 07, 2007 08:02PM

Alright, so I bought Roald's old k-star kit.

According to him:

"70cc K-star. New piston-ring (40 miles old) with reserve piston-ring (new). Modified exhaustport (67% of the bore and 1mm higher) and modified piston (1mm shortened and booster-ports dremeled. Booster-ports don’t look too fancy)"

So, what should I expect to have to do when I try to mount this sucker up? I searched for more k-star info on here and it looks like mixed reviews. Is there much to do for case matching? I don't want to have to work too hard for this one. haha

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Re: 70cc k-star kit

Flagrant - /
stevew
Dec 07, 2007 08:26PM

Th transfer ports are quite large so if you match the case you will be removing a lot of material. I have both the RGD and K-Star and they are almost identicle. Almost have the RGD hooked up. Exhaust port is already large and if you have an aggressive pipe it won't make much diff if it has been enlarged. Both of these kits are very well made and I expect some big torque performance. Those boost ports mainly route some cool charge through the under piston to keep it cooler

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Re: 70cc k-star kit

I.R.E. Mike Pee /
mijunkin OP
Dec 07, 2007 08:38PM

So if I don't case match or match the boost ports will I have problems? Just asking because I know the polini will burn the shit out of the piston if you don't match it well. I've never seen a k-star, and it'll be a while since it's coming from the Netherlands, so I just wanted to ask to see what I'm in for.

So, basically, can I just slap it on and go? Or will it take more work? I'm not convinced I'll keep the k-star, so I don't want to do too much dremel work on a case I might not keep it on.

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Re: 70cc k-star kit

Flagrant - /
stevew
Dec 07, 2007 09:16PM

Well the difference between the stk case transfers and this kit are very large. Try it without altering the case and if you experience no tuning difficulties what the hell. This kit shouldn't burn up due to the difference. Except for the boost ports it just looks like an exaggerated version of a stock cylinder

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Re: 70cc k-star kit

I.R.E. Mike Pee /
mijunkin OP
Dec 07, 2007 10:19PM

Sweet, thanks dude. If I decide to keep it on, I'll be asking you for some matching and porting tips.

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Re: 70cc k-star kit

I.R.E. Mike Pee /
mijunkin OP
Dec 08, 2007 02:02AM

Also, the age-old lame question: What jet should I run with the k-star, a 15mm bing, a high flow filter, and a techno boss? Just looking for a starting ground, or what others have used. I can adjust from there.

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Re: 70cc k-star kit

Brennan O. /
brennano
Dec 08, 2007 03:39AM

if you match transfers low 90s, if you dont then high 80s. get rid of that boss too!

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Re: 70cc k-star kit

I.R.E. Mike Pee /
mijunkin OP
Dec 08, 2007 10:23AM

The boss is an alright pipe. I've got an estoril layin around here though...maybe I'll use that.

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Re: 70cc k-star kit

SchijnHeilig /
schijnheilig
Dec 08, 2007 11:41AM

You don't have to match the case. It will run fine without matching. However, when you do match the case it will perform slightly better.

The booster-ports in the piston are mainly for cooling and lubrication. They were there stock, but they were pretty small, so I matched them (roughly) to the ports in the cilinder.

I ran a 74 jet with 15mm Bing, Biturbo and modified stock filter. So I think you should be around the high 70's, low 80's. Depending on how hot it is there. Shall I throw in a 78 jet for you, or something? ;)

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