Thread: 1998 GP 800 porposing
06-15-2008, 09:51 PM #1
1998 GP 800 porposing
I was woundering if you yamaha guys could help me out..
I have a friend of mine who has a 1998 GP 800.He has been recently noticing it porposing at high speeds..I understand the porposing on a RXP but what causes and fixes are avaliable for this old of yamaha ski???Thanks guys for all your help..
06-15-2008, 10:00 PM #2
what ride plate and sponsons is your friend using?
06-15-2008, 10:24 PM #3
06-15-2008, 10:36 PM #4
i would shim the ride plate in front down a bit and try to get some after market sponsons. I really think its the sponsons. Does he have them both set at the same height? I reallly hated them. they were junk.
06-16-2008, 08:42 AM #5
Yes they are both at the same height..He had them all the way up and tried them all the way down..This is what i dont get..He said when he had them all the way up the ski would turn on a dime..When he put them all the way down it would feel loose and spin real easy when taking a turn???? To me thats completely opposite of what i know about sponsons..What sponsons do you guys recommend??Riva,R&D??
06-16-2008, 09:10 AM #6
Hey there Snoman..
Like Kris said,
The stock sponsons are J-U-N-K..!!!
Get some aftermarket one's on there..
Anything is better than the YAS crapola..!!!
Fucck even a couple of lumps of wood cut to shape would be better..
Through the up = handle's better, down = spins out, don't make sense..??
Ebay or post a WTB in the classified's is your first step..
Some are easy to attach to the ski,(Riva) some are pretty damn awkward (beach house.. (mine.!))
Good luck with the search..
PS.. the GP's porpoise like a S,O,a B, at the best of times anyway..
06-16-2008, 10:58 AM #7
06-16-2008, 09:07 PM #8
- Join Date
- Feb 2007
- Bellmore, NY
spent over 500 bucks and am still tweaking the poropouse off of my machine. the beach house suck balls to put on, but the adjustments well make up for it.
if you want to get rid of it, r&d trim tabs, plate and grate, and definately sponsons. it worked for me!!!
06-17-2008, 12:29 PM #9
- Join Date
- Mar 2008
- Carrollton, TX
Girlfriend had the same ski with the same problem.
Solution- R&D ride plate, intake grate. Then shim with 2 stainless washers on each side the 2 rear mounting bolts of the ride plate. As mentioned either replace or adjust the stock sponsons almost all the way down(what I did).
06-17-2008, 12:45 PM #10
R&D rideplate or Riva pro plate....stay away from the "groovy" plate it sucks. R&D intake grate or Pro-tec intake grate. Aftermarket sponsons (anyone's) just get rid of the stock ones unless you modify them to go further up or down. You might have to shim the ride plate with a couple of washers. Unless it's an early '98 hull you probably don't need the trim tabs. I never ran them on my '99.
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