GP1200 INTAKE GRATE

[dukeno1]

Bryan, I have a 98 Gp1200 that has been mildly ported, oversized pistons, riva f/a's, and has had head milled. Also have a skattrak super slimline prop. I have a couple of questions....
Since the rebuild she runs very strong. However,now when letting off of the gas from wot, the front end dives dramatically, almost pitching you off if not careful! A

[dukeno1]

Whoops!

let me continue....It was found by experimentation with another similarly modded gp that a 1100 raider intake grate with the center bars removed completely eliminated this nose dive AND added 1-1.5 mph on glass water! So I have one of those on mine now. My question is have you heard of this before? What type of setup do you think might work better if any? I have the stock plate and riva trim tabs but still porpoise a lot...almost impossible to ride with someone else. Also have stock sponsons all the way up right now. Any advice would be appreciated....

Thanks

ps What is your opinion on the tdr waterbox...I have one of those on also and definitely feel harder acceleration. How does it compare performance wise to stock?

[Bryan Glynn]

I have never seen teh TDR box give any performance advantage, just more noise. The stock box is more than enough for a stock GP1200.

I would put your sponsons between 1/2 way and full down to help with the bounce, aalso try shimming the back bolts of your rideplate with a few washers. You will loose some top-end speed though.

If your stock intage grate makes you nose dive too much you can do as you did with the raider grate, or get a scoop grate to keep it sucked down. If you ride on glass stay with what you have.

[dukeno1]

Thanks Bryan

I will try the shims at the rear and see what happens...