1200cc Triple Tuning Help

dukenukem

dukenukem

Location
Orlando, FL
I'm looking for reassurance to tuning my 97 GP1200. I had to rebuild the ski due to oil starvation (lesson learned, blockoff in place). The cylinders were ported by someone, and the stock head has been modified to produce 150psi. The ski has a R&D intake grate, Prok F/As, Ride plate, protec nozzle, Premix, and a skat 14/20 impeller. I had one cylinder resleeved, and all of them bored out to 1 over with matching wisco rebuild kit. I've ran approximately 4 tanks throught the ski at 32:1, and am ready to do the final tuning.

The Yamaha factory specs are:
Main Jet: 135
Pilot: 100(1), 95(2) 97.5(3)
Seat: 1.5
High Speed needle: 1/2(1&3), 7/8(2)

Currently, I'm running:
Main Jet: 135
Pilot: 92.5(1,2&3)
Seat: 1.5
High Speed needle: 2(1,2&3)
Low: 1.5(1,2&3)

I don't ride this ski that much, so I want to make sure this thing is completely setup. I'm definitely NOT tuning savvy, but want to make sure I'm in the ballpark. Thanks for all your help... And to anyone local I have cold beverages for assistance :D
 
JonnyB

JonnyB

Location
Round Rock, TX
just got your PM thought I would post it here for everyone to see

really wish I could see a pic of the porting or knew who did it but just with the specs you gave me this is really the best I can do

110L
135H
1.5 N/S 115g

Edit how old are the carbs the check valves are prone to fail I would look into a remove fuel pump
 
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dukenukem

dukenukem

Location
Orlando, FL
JonnyB said:
just got your PM thought I would post it here for everyone to see

really wish I could see a pic of the porting or knew who did it but just with the specs you gave me this is really the best I can do

110L
135H
1.5 N/S 115g
Click to expand...

I'm sure I have some pics around of the porting from the rebuild, I'll see if I can find some clear shots. I asked the performance shop (which did the work, i assembled)about how extreme the porting was, and the only answer I could get was, "Medium." When I asked about the head modifications, I got the same answer.
Thanks for getting back to me so quickly, I'll source those pics.
Thanks again,
Dylan
 
JonnyB

JonnyB

Location
Round Rock, TX
dukenukem said:
I'm sure I have some pics around of the porting from the rebuild, I'll see if I can find some clear shots. I asked the performance shop (which did the work, i assembled)about how extreme the porting was, and the only answer I could get was, "Medium." When I asked about the head modifications, I got the same answer.
Thanks for getting back to me so quickly, I'll source those pics.
Thanks again,
Dylan
Click to expand...

If you want to pull the head take the measurement from the top of the cyl to the top of the exhaust port mild porting would put you at about 36mm

Edit: are you dealing with windowed pistons? if so that messes with jetting too, 150PSI is a good comp for pump gas I have a few diff domes run 175 to 205
 
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dukenukem

dukenukem

Location
Orlando, FL
JonnyB said:
If you want to pull the head take the measurement from the top of the cyl to the top of the exhaust port mild porting would put you at about 36mm

Edit: are you dealing with windowed pistons? if so that messes with jetting too
Click to expand...

I'll get a measurement tonight for sure, and take some pics of what I have. The old pics I have are blurry at best, and don't really show the porting. I should have documented better... Hindsight is always 20/20 :doh:

EDIT: No windowed pistons to my knowledge, just the regular Wisco rebuild kit. Cylinders were matched to the pistons.
 
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JonnyB

JonnyB

Location
Round Rock, TX
dukenukem said:
I'll get a measurement tonight for sure, and take some pics of what I have. The old pics I have are blurry at best, and don't really show the porting. I should have documented better... Hindsight is always 20/20 :doh:

EDIT: No windowed pistons to my knowledge, just the regular Wisco rebuild kit. Cylinders were matched to the pistons.
Click to expand...

There is a guy out in Oceanside, Ca not too far from you if you need any help too
 
JonnyB

JonnyB

Location
Round Rock, TX
dukenukem said:
Who is the expert? I've ridden with the Oceanside crew a few times. As a matter of fact, my friend rode the GP last time in case the Blaster needed a tow.
Click to expand...

PM OsideBill on greenhulk.net great guy be warned he is a couch rider but he has been around the 65Us for awhile now and would be a great asset to know
 
dukenukem

dukenukem

Location
Orlando, FL
The pictures aren't the best, but you get the idea. I also was having an issue getting accurate readings of the depth, so I'm grabbing a sturdier metric ruler from work to re-measure tonight.

Pics:

August002.jpg


August001.jpg


August003.jpg
 
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