Thread: 70mph not getting closer??
09-16-2014, 08:01 PM #1
70mph not getting closer??
GP1200r Finally Running perfect. So I Want to see 70mph Here are the mods on the ski so far.
stock 1200r motor 80hours 125psi on all 3 cylinders
riva flame arestor kit and carbs jetted to osidebills recs.
riva ride plate
riva free flow exhaust
riva intake grate
oem trim tabs
oem sponsons on the down position
pump is sealed
ive done most these mods to see no gain in speed and maybe even a loss of speed. what needs to change???
09-16-2014, 08:18 PM #2
- Join Date
- Jul 2014
- Canyon Lake, TX
pretty sure the sponsons should be all the way up for top end..
do you have a tachometer so you can see actual RPM'S?
when i rejetted and balanced carbs i seem to be getting less rpm, but just looking at the tach, seems like im only achieving 7100.
im getting 61.5mph
09-16-2014, 08:19 PM #3
(1) free flow you will lose speed with that set up.
(2) oem sponsons down you will lose speed step them instead.
(3) 14/20 is to much for that set up you should of got a 13/19
(4) if you really want good gains go with the FF plate.
09-16-2014, 08:39 PM #4
ok so switching back to my stock exhaust.
what is stepping sponsons?
ill place an order for 13/19 (ordered Just now!)
sending you my plate Jim, Thanks for the advise.
anything else im missing?
09-16-2014, 09:27 PM #5
ok so far ive stepped the sponsons tonight, ordered the 13/19, just put my stock exhaust back, also ordered the extended nozzle hoping that will help some. and i will be placing an order for my plate to get the ff mod from Mr jim. should i put my stock 1200 grate back on and ditch the riva?
09-16-2014, 11:12 PM #6
Definitely do not use the stock grate at 70mph. But on the rideplate I think Jim can MOD it but I think the FF MOD is only for the r&d plate but I should let Jim answer that really.
09-17-2014, 12:39 PM #7
You are now realizing that the BS that Riva puts out regarding their stage I & II performance kits is bunk. Yes they are bolt on items you will need but not provide real speed gains .... until you do something to improve & step up RPMs & advance / change the timing. You can have the heads milled. This Jim, can do also ... about $100 includes shipping (quick turn around). You could install a 3* or 4* keyway this will advance the timing. Or even find a reflash for the ski. Until you increase the RPMs, the 14/20 prop is just to much to offer any real speed gain. Ask me, how I know? It is a must you get a good tach. Then after milling the heads & keyway you will need a fuel controller .. to help reg & feed more fuel to injectors. As you can see, there are mods that can really offer substantial more speed top end ... but it will take $$. I sit right @ 70 mph on my GPS. To get more I will be porting my cyl. & installing the VFIII reeds. It really is addictive LOL. Keep asking Jim & Rich, @ WFO they are experts ... just know it never really stops. Good Luck
09-18-2014, 06:51 AM #8
- Join Date
- Aug 2006
I vote for getting head milled and the FF plate. One of our families boats had same mods as yours, with 145 compression and a angle milled stock plate and was just a shade over 70. You have about all the right stuff, study threads about rideplate angle and such and you should be able to get there with what you have and a couple of additions.
10-01-2014, 04:37 PM #9
ok threw on my 13/19 prop yesterday and went for a ride. 61mph on the candoo gps system, even with the ff plate i dont see this ski getting anywhere near 70mph. mods are as follows.
gp1200r motor 80hrs 125psi accross the board
solas 13/19 impeller
riva flame arrestors at osidebils carb recs.
riva ride plate
riva intake grate
*new* oem reeds
im guessing getting my head milled and having jim modify the ride plate is the only way to get some more umffff out of her.
what needs to be done once the heads get milled??? do i have to change jetting in the carbs or just raise the fuel delivery? do i need to run different fuel?
10-01-2014, 04:48 PM #10
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By jamesrini79 in forum 4-Tec PerformanceReplies: 26Last Post: 08-10-2007, 08:48 PM
By flyboy in forum Yamaha PWC Performance (2-stroke)Replies: 22Last Post: 07-03-2007, 09:40 PM
By NateGP1300R in forum Yamaha PWC Performance (2-stroke)Replies: 5Last Post: 05-30-2007, 12:11 AM
By reisenback in forum Kawasaki PWC Performance (4-stroke)Replies: 31Last Post: 01-25-2007, 09:34 PM
By RXPBeast in forum Sea Doo Open DiscussionReplies: 11Last Post: 06-11-2006, 09:32 PM