Thread: GP800R Missing #1 Power Valve
08-07-2014, 08:09 AM #1
GP800R Missing #1 Power Valve
So, a little back story here since I'm still a relative newb and I took a season off from riding last year while busy with work.
I picked up a very nice 2003 GP800R for my girlfriend to ride with me when I get out on my GP1300R. I picked it up from an older gentleman toward the end of last summer. The ski has about 75 hours on it, has complete service history, is super clean, and basically checked out. He lived on water so we were able to check it out half-decent and I compression tested it once it had some heat in it to confirm it was solid before I loaded it up. It all seemed to check out.
Although I'm a power valve newb, I knew I needed to get some Wave Eater clips in it ASAP, so the following day I ordered some. I never got around to riding last season, so I winterized the ski and just stored it in the shop with the clips ready to install.
Fast forward to yesterday. I'm up near my lake house for work, and I'm ready to do some riding this weekend. I went ahead and tore the exhaust off yesterday evening to do the Wave Eater installation. Started out pulling the cover on the back cylinder and saw just how simple this mod is. Opened up the front cylinder valve cover and the look on my face was probably a good one.
From what I can tell as a newb, I've got nothing there. There's no valve or remains that I could tell. All I've got is a bushing held in by the allen bolt. I'm guessing this is what was once part of the power valve assembly that the shaft is supposed to be riding on. I've got nothing else, and although I was running out of daylight by the time I picked my jaw back up and started to inspect this last night, I shot some photos with my phone to get a better view in there. I'm pretty certain I can see the piston and that there's nothing left in there. Feeling through from the exhaust side I don't feel anything abnormal. Felt like piston and rings. Unlike the sealed side, there's no oil gunk or buildup since it was free to flow back into the cylinder.
My first thought was that I was about to pull the engine, tear it down, and fix it. Now I've done some searches and it seems there are a few rare instances where these things have come apart in pieces on the triples and blown straight out of the exhaust with little to no damage. The difference there being that they have a cat to catch the pieces and I don't here with this little guy.
It seems to me that this thing would run a lot worse if it was really hurt from this. As it is, it fires up, runs with no noise, and has excellent compression.
I'm going to pull the head off of it this afternoon and see how things look. Obviously it's going to need a power valve, but being the lunatic that I am, I'm thinking that if this thing is truly clear of the valve, it's getting ridden this weekend. (I want to go fast on my 1300, I don't need her riding on there with me!) I'll order a couple replacement valves and install them when they arrive. It's obviously been running this way for quite some time, so other than being down on umph from a missing valve, I'm leaning toward letting her eat sans the valve for a few hours.
I really have nothing more technical to add to this long ridiculous ramble. I just thought I'd post up about this since I find it kind of interesting. I know power valves and their issues have been beat to death a decade ago, that this ski is 11 years old, and that it's not a modded triple. I just figured it was ridiculous enough to mention.
I'll update this thread as I get the chance with some info and probably photos with the head off. I'll also try to upload a photo from my phone real quick here to show the missing valve.
08-07-2014, 09:58 AM #2
Edit: Need to update my file hosting settings in a moment to share the photo...
08-07-2014, 10:10 AM #3
- Join Date
- Jun 2010
- Milwaukee WI
Is there any chance the valve was just removed by someone because they had an issue with it?
08-07-2014, 04:27 PM #4
if everything looks good when you remove the head before you install the new valve , push the valve on cylinder slot and push it all the way down and rotate the engine by hand to make sure it doesn't touch the piston.
08-07-2014, 04:45 PM #5
08-08-2014, 08:09 AM #6
It's very interesting, as are the other cases. This is what I got when I pulled the head and wiped the salt that fell onto the pistons mostly off. Head is perfect. Not a single little ding or nick.
It'll be on the lake tomorrow for my girlfriend to putt around on. Next week I'll get a new valve in her... Probably will replace both for piece of mind while the pipe is back off...
I'm just glad I'm not swapping pistons or heads and refinishing a cylinder over it. The thing doesn't seem like it was ever torn down and the service history doesn't show it. I wonder how long it has been sans a valve?
08-08-2014, 11:20 AM #7
I hope you are not thinking on reusing the head gasket . Remember to slide the new valve all the way down and rotate the engine by hand to make sure it doesn't touch the piston , make sure to install the valve correctly.
08-08-2014, 01:09 PM #8
- Join Date
- Jul 2007
Fuel mixture is way rich on mag cylinder. Is that the cylinder missing the valve? When you took compression readings before you bought it you should have noticed a difference in compression from the each cylinder.
08-08-2014, 01:32 PM #9
I have three valves listed in the classified section BTW.
08-11-2014, 09:11 AM #10
I cleaned that head gasket, sprayed it with copper, and reused it for the weekend (gasps). I race and tune cars, so working on the ski seven hours from my shop sort of reminded me of being away at a race weekend and getting a car back together in the pits with what you have to get by for the rest of the race. It ran fine yesterday for my girlfriend and my other friend when they rode it. Of course they just cruise around and probably wouldn't know if it had power or not.
I've already got some parts on the way to get this thing back in shape (obviously including a new head gasket since it only takes a few minutes to pull the head and swap it out). Once it's back up and running the way it should I'll focus on tuning it. Should be back on the water again in two weeks.
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