Thread: 02 gp1200r powervalve missing
09-05-2011, 10:28 PM #1
02 gp1200r powervalve missing
I have an 02 gpr with 5 hours on a reman engine. I had it out last weekend and heard a rattle coming from engine when it was at an idle. I also noticed it bogged down at low rpms. It ran great once I got it up and going. Quit riding right away and went home and pulled the plugs. # 1 and 2 looked good but # 3 was a lot wetter. Pistons looked good too. I tested the compression - 115, 115, 108. I thought the 108 was low but I wasn't sure what to do. Put new plugs in and took it back out today. It ran fine until I put it on the trailer and it wouln't rev, it would just spit and sputter. Got it home and tested again - 115, 115, and # 3 was 105 this time. I pulled the head off and found the powervalve was gone. About 20% of it was hanging in there yet. Everything was still attached it had just split down one side. What would cause this? The piston had a chunk missing out of the corner where the powervalve had caught it but the cylinder was fine. I am going to assume the missing piece is in the exhaust somewhere. The head looks fine too. I have warranty on this engine so all I'm out is my time pulling it again and some shipping but I'm more curious what caused this to happen. Is it something I did or just faulty equiptment? This engine is from SBT by the way. I switched it to premix and put on waveeater couplers. SBT claimed they put on thier own version of the clips. I'm fairly new to this (5 hours riding time and it looks like I'm heading towards my second engine transplant) I was wondering if some of you guys who've been around a powervalve engine more have seen this before.
09-06-2011, 06:04 AM #2
- Join Date
- Jan 2006
- Texas City, Texas
It is unfortunate that of the ills the 66v engine has, the power valves seem to be the biggest weakness and it greatest strength. The wave eater couplers do help tremendously I've been told not because they keep the valves from breaking, but because they minimize the damage when something goes wrong. It is a case of which came first the chicken or egg. Piston ring catches the valve, valves catches the ring, rings spin because the pins fall out.... the list goes on and on. Bottom line is that you have an engine down.
It seems that SBT does not have a good reputation for the 66V engine, although in all fairness they seem to do well with the Seadoos. I myself bought a rebuilt crank from them years ago that lasted all of 15 minutes before it went bad. It was the last time I ever delt with them.
My fix for the power valve issue was to go to the gas power valves. They are expensive and give no real power gains. They do however give you complete protection from a valve falling into the moving piston because the have a big shoulder built right into the shaft that keeps this very thing from happening. They are easy to remove and clean as well. In the 11 years that I have owned my GPR, one valve has broken (which is rare in itself). The only symptom I had was that I lost 300 rpm. I replaced it and went on about my business with no other issues.
09-06-2011, 05:51 PM #3
can you take the cover off one of the other power valves and snap a pic. i would love to see one of these "SBT version of a wave eater clip"
09-06-2011, 07:44 PM #4
Here is a picture of the back two cylinders. The one on the right has the piece mising out of the piston. That's the one that dropped the powervalve. When I took the head off the piston was a lot wetter on top than the others and the powervalve was bone dry unlike the others. I am assuming that is a result of the loss of compression. I had ordered waveeater clips for this engine before I got it. Went to put them on and they wouldn't fit so I called SBT and that's when they told me that they put their own version of them on.
Thanks for the tip Salty, I've read about the gas powervalves on here and I will do a search and read up on them some more. Like I said this engine is under warranty so I'm going to get the same setup back but I am going to look for another GPR with a bad motor over the winter (the winters in Iowa can be pretty long) and try to do it "right". From what I've read on here there is an almost endless amount of performance you can get out of these. Just takes time and $$$.
09-06-2011, 07:59 PM #5
Ok I guess I don't know how to get pictures on here. The best I can describe it is the waveeater clips were not wide enough to go over the top of the powervalves. The SBT version wasn't the problem as far as i know. The powervalve actually split, fell into the cylinder, and dissapeared. No shavings, nicks, or schatches on the cylinder. Maybe someone else on here has a picture of these "SBT clips" they can put up or tips on how to get a picture on here.
09-07-2011, 07:28 PM #6
it sounds like the winter project wrench bug had bit you as well. i hope you get your warrantied engine back before the water gets too cold.most ppl use photo bucket account to upload pics.
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