06-18-2014, 10:24 PM #1
Moded GP1200R. Am I headed in the right direction?
My latest ski is a GP1200R I picked up about a month ago with 91 hrs. Mods are: shaved stock head (135# on all 3 jugs), rebuilt & jetted carbs, flame arrestors, free-flow, wave eater clips, premix, prime kit, tto tach, fuel pressure gauge, 13/19 prop, R&D ride plate. Top speed was 65.9 last wknd on gps @ 7240 rpm (I think this is decent w/ 13/19, but you can tell me what you think) I ordered a Jim's plate, and it just came in yesterday so I plan to put it on as soon as I have time. 1st question: is the compression where it should be for a shaved stock head? (15 thsnd) 2nd question, is the freeflow hurting my top-end? 3rd ques, do I have enough power to spin a 14/20 prop for more top-end? And last but not least, how difficult is it to change to an '05 pump? Hole shot suffers right now, im guessing due to the small pump (feels like its spinning), but once hooked up it has great mid-range. My goal is to get to 70-72 on this motor, increase my holeshot (perhaps with an '05-up pump) & not lose too much mid-range. Suggestions??? Thanks all! BTW...Run was with: 190lbs, smooth to light chop, 400 ft asl, 87f.
06-18-2014, 10:27 PM #2
Forgot, also has D-plate & Riva toploader intake grate.
06-19-2014, 07:40 AM #3
I would say that's about right. How much fuel did you have and I'm guess you are running a solas prop?
06-19-2014, 08:14 AM #4
Is the pump sealed? *pump stuffer
my heavier XLT with R&D Grate, Solas 13/19, R&D plate, D plate, FA, Island tunes carbs(Fuel Accel delete) with Stock Exhaust & stock head reads 72mph at best. I gotta GPS it but Im thinking about 65real world mph. my mods yielded a 12mph increase on the cluster.
06-19-2014, 09:00 AM #5
Almost - Thanks for the reply...
I had 2-bars on the fuel gauge with my best run of 65.9. The 1st time I ran it with at least 3/4 tank @ 65.2 with trim 1-click down. At 4-bars I ran it again with trim in neutral @ 65.1. By the time I ran it the last time, I was at 2-bars of fuel, ran it back to back, 1st time trim in neutral at 65.4, then trim 1-click down again and got the best of 65.9. Surprisingly it ran it's best with trim 1-click down. I'm thinking once I get the Jim's plat on, get everything shimmed correctly, step the sponsons, I should be able to get my best MPH with the trim in neutral, but we'll see. Not sure if it's a Solas or not. I believe that's what the previous owner said, but there was so much stuff he tolk me not 100% sure of the brand.
RaiderMagic - Thanks for the reply... It's supposed to have a pump seal kit (sorry forgot to mention it). I have no reason to think it doesn't... previous owner did the mods to this ski & so far everything he said it has, it does). My dreamometer registered 75-76mph. I know they vary depending on the ski... My GP1300R used to register 77mph, but GPS says 65-66 (depending on the day).
Anyone have any answers/opinions on whether I have enough power to turn the 14/20, and will this get me to my goal o f70-72mph?? How much mid-range will I lose? How difficult is it to install an '05-up pump? If I'm going to change the prop, this would be a good time to change the pump. Also, where is the best place to by the larger pump? Should I look for a used one, or should I buy it from the OEM parts section from RIVA?
06-21-2014, 04:48 AM #6
- Join Date
- May 2013
i have a 05 pump
06-21-2014, 08:51 PM #7
Today I ran a 63.7 one way and 64.7 the other on tidal water in the back bay. This is on the stock plate and half tank.
06-21-2014, 09:10 PM #8
Yamaha1390, does it include everything I need to change it out, or what additional parts would I need? Safe to assume it's in good working order, do you know how many hiurs that are on it? Just let me know what you want for it,.. you can pm me if you want. Thanks yama1390
06-21-2014, 09:13 PM #9
06-22-2014, 09:03 AM #10
Never checked compression, but I just cracked 20 hrs on a full rebuild. Stock head.
Edit: I'm going out again and I will give it ago with less fuel. It's kind of windy today so will see if I can find a good spot with minimal tidal flow out of the wind.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By Image0r in forum Polaris Open DiscussionReplies: 2Last Post: 08-11-2013, 04:48 PM
By Racer26 in forum Polaris Open DiscussionReplies: 21Last Post: 01-06-2012, 10:54 AM
By boostedgta in forum Open DiscussionReplies: 13Last Post: 06-02-2010, 12:10 PM
By Mike H in forum Videos & PicturesReplies: 0Last Post: 02-13-2010, 12:53 AM
By Ska in forum Yamaha PWC Performance (2-stroke)Replies: 11Last Post: 02-07-2010, 01:43 PM