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  1. #1

    97 gp 1200 jetting help

    Hey everyone. I've been browsing this forum for a few months now without becoming a member. So far I've been able to find everything I need without asking any questions. I'm kindof lost at this point and could use some advice. I have the 65u motor and power plenum flame arrestor, tdr water box baffled. I am having trouble tuning the ski, seems to bog at wot after a few mins of use. I used to just restore the mixture screws to factory settings and it worked great but now that I have the tdr water box I am not able to tune it no matter how hard I try. Part of the problem is I cannot find mixture screws anywhere for this motor with the t handles. Also I am wondering if I maybe have to get new jets because of the flame arrestors and because of the new water box. Any help would be appreciated, just trying to find the right combination of settings so I can enjoy myself like when I had a completely stock ski.


  2. #2
    Yamaha artisan Cutlass's Avatar
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    Read this thread on "How to make your own T-handles"

    Here's the specs I use:
    135 mains. 100 pilots. 1.5 N/S and 115 gram spring.
    Highs out 1 1/2 turns. Low out 1 1/4 turns.

    I have a 65U with 84.5mm Pro X pistons and Riva Flame Arrestors

  3. #3
    Thanks I am going to look into that t handle trick. I am thinking about the return line mod do you know if that's necessary to balance the fuel pressure after doing the jets? Also is there any reason why I shouldn't buy some higher psi heads before I do the jetting? I still want to run 91 octane though.

  4. #4
    Yamaha artisan Cutlass's Avatar
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    I like the idea of the return line fuel pressure balance mod and in fact I did that to mine.
    A higher compression head won't require you to rejet from the above specs. You might have to crank the high and low speed adjusters a bit, but the same jetting should work fine.

  5. #5

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    The 115 gram spring is the gold one if you didn't know.

  6. #6
    Yamaha artisan Cutlass's Avatar
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    Used to be gold. Now its "Platinum"....not sure how to tell the difference between silver and "Platinum"

  7. #7

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    that's a trick way to make T handles ,in the past I've used yellow electrical wire nuts,pulled coil out of inside and ground down face of nut,It make a perfect press fit

  8. #8
    thanks guys for all the info. I am in the process of buying a popoff tester as well as a new carb kit because i threw away the larger springs from my mikuni rebuild kits......

  9. #9
    Hey everyone and I've had my fun and I've had my fair share of tuning issues along the way. I never re-jetted and i think its time to do that. I didnt buy a popoff tester but i made one. My popoff is 30~32 for each carb. I noticed some creased check valves 3 times this season. It only is the check valve closest to the pulse pump, never the one closest to the carb body. I got a tach/hour meter from works conn. To help with tuning. I replaced all the creased valves with genuine mikuni parts, added a 105 main jet to a T in the return line, got a new fuel filter secondary, got all new fuel line from honda. Sealed off the front hood around the base, added an electric bilge pump, greased the stator and intermediate shaft, got 2 new sets of plugs.. etc i will be testing today in Oceanside ca. If i still have problems im doubling up the skinny long check valves, ordering 1.5 needle and seat, new mains and pilots.

    My question is, whats the correct popoff pressure. My carbs are at 30~ and im not sure of the needle and seat size.......

  10. #10

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    97 gp 1200 jetting help

    Popoff is based on your spring and needle combo. The 65u usually has a high Popoff due to the shakiness. Bases on your first post the high speed screws are out too far. Cylinder 1&2 are 1/2 turn and cylinder 3 is 7/8 turn +/- 1/4 turn. At least for stock jetting. I did the same thing one day and was trying to tune from 1.5 turns and I was unsuccessful until I referenced the manual again and realized my mistake.

    Edit: sorry I read cutlass' post as yours.
    Cutlass, do u run 1.5 turns on the highs? I was way rich with them out that far.
    Last edited by akjose; 09-11-2012 at 02:41 PM.

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