Gran Turismo GT200 Big block - PHBH 30 Jetting Advice Please

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Bidsy
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Sun Feb 10, 2019 3:14 pm

Hi
Just built a Gran Turismo GT200 Big block engine and after some jetting recommendation please.
My set up is 30mm PHBH, BGM V4 clubman, 18/47 SX200 gearing.

Anybody with a similar setup?

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garry inglis
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Sun Feb 10, 2019 3:36 pm

145 main 55 pilot av266 an x7 second clip should get you started then check plug for fine tuning

Bidsy
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Sun Feb 10, 2019 10:00 pm

Is a 145 main a little bit rich

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garry inglis
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Mon Feb 11, 2019 9:04 am

It's a freshly built engine and you want it rich and for the first 500 miles you won't hit full throttle to use the main properly as I said it's a starting point as you put the miles on do plug checks but from what I've seen posted over the years with jetting for this kit they end up on 140/145 That's why you start rich

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Bidsy
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Mon Feb 11, 2019 10:42 am

Thanks Garry, better order so more jets then. Cheers

Lambretta Sash
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Sat Mar 02, 2019 10:13 am

After building a few and running Gt200 on my lammy for a few years, here's my set up with TT evo pipe and not much different with Ron moss pipe. Final ratio 4.6 using close ratio box
140 main 55 pilot 40 slide x13 av268

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kejj
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Sat Mar 02, 2019 9:33 pm

With a v2 bgm i never went further up than 135. Now setting up with fran race and egt I am at 134. Flat out motorway speed.


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________________________
Lambretta LiS150 1965 - MBGM RT195 w/MBGM Clubman & Keihin PWK28
Lambretta TV175 1962 - GranTurismo 200 w/MBGM Clubman & Dellorto PHBH 28
http://tv175.wordpress.com/

Davidsquaredson
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Fri Apr 19, 2019 4:57 pm

Gt200. 28mm Delly. Breathsweet foam and big rubber elbow. Pm tuning Evo pipe. Choke 60. Idle 52. Slide 40. Av268 atomizer. My main is 134. X13 needle. When I had a big big clubman (gen 1) my main was 130.

It starts 1st kick cold with the choke on and not touching the throttle.

I was not happy when I had the big box clubman on it. I could not get the mid range perfect on it. When I put the pm pipe on it, it cleaned it up perfectly. And now at 3,200 rpm I get pushed back in my seat.

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carpe scooter diem

1974 Rally 200
1965 Li150
1963 TV175
1974 Eibar Jet200

Davidsquaredson
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Fri Apr 19, 2019 4:59 pm

Davidsquaredson wrote:Gt200. 28mm Delly. Breathsweet foam and big rubber elbow. Pm tuning Evo pipe. Choke 60. Idle 52. Slide 40. Av268 atomizer. My main is 134. X13 needle. When I had a big big clubman (gen 1) my main was 130.

It starts 1st kick cold with the choke on and not touching the throttle.

I was not happy when I had the big box clubman on it. I could not get the mid range perfect on it. When I put the pm pipe on it, it cleaned it up perfectly. And now at 3,200 rpm I get pushed back in my seat.

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After reading the others, I'm going to raise my main to 140 and see what it's like.

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carpe scooter diem

1974 Rally 200
1965 Li150
1963 TV175
1974 Eibar Jet200

Davidsquaredson
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Posts: 174
Joined: Sun Jun 10, 2012 11:41 am
Main scooter: Early Eibar Jet 200
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Sat Apr 27, 2019 3:05 pm

Bidsy wrote:Hi
Just built a Gran Turismo GT200 Big block engine and after some jetting recommendation please.
My set up is 30mm PHBH, BGM V4 clubman, 18/47 SX200 gearing.

Anybody with a similar setup?
Hi Bidsy,
My jet200 has the same setup. I'm trying to figure out the right exhaust to match the sx200 gear box. With the v3 bigbox, how is the behaviour going from 3rd to 4th, how is acceleration in 4th, and what's the top speed?

I've been going back over forum posts and there is a lot of discussion on this topic but I'm not finding anyone with SX gearing. I'm sure it's in there, but needle in a haystack.

Btw, I had a v1 bigbox on my scooter when I first put the GT on, but I didn't have it jetted correctly and quickly put a expansion on it that I had laying around.



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carpe scooter diem

1974 Rally 200
1965 Li150
1963 TV175
1974 Eibar Jet200

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