Thread: 951 XPL twin pipe water problem
11-09-2009, 02:48 PM #1
951 XPL twin pipe water problem
I have just rebuilt the motor and installed twin Factory Pipes at the same time. The problem is that it runs good on the trailer and then when put in the water it runs on rear cylinder only as water is somehow getting in front cylinder. I have checked the offending cylinders manifold for pressure etc and is fine (running dual reverse cooling) also checked head gasket and head, all seem ok as new gaskets were used throughout. Does anyone have any ideas before I am forced to strip it back down
All help is appreciated
11-10-2009, 02:14 PM #2
You have a leak at the gasket for the head pipe or a cracked head pipe
11-12-2009, 07:38 PM #3
what have you found?? can you run it on the flush hose to verify?
11-13-2009, 03:09 PM #4
Going to test a few things on Saturday, have tested manifold/headpipe and that checked ok as did gasket. Going to start with the front chamber and check from there. I also need to fabricate some kind of flush device/fitting possibly with a 1/2 inch y connecter as I am now using the original flush fitting for a second water line in.
11-16-2009, 08:05 AM #5
The twins sure are fun arent they!! What are you running for carbs?
11-16-2009, 12:33 PM #6
Using the stock carbs at the moment,I know that aint the best setup but used Novi's are like rocking horse crap around here ! I would just like to sort this problem out so I can concentrate on setup.
I have pressure checked the manifolds and chambers and found no leaks there. Did a compression check and that looks fine at 150 in each pot. Wondering what else I can do before the dreaded strip down.
11-16-2009, 03:32 PM #7
How do you know that water is entering the front cylinder what are the effects . If water is present that bore will usually run a lot hotter , what do both plugs look like after running it . Are you 100% that water is the culprit ? You need to verify this first
The twins are notorious for leaks at the cylinder gasket area. From memory I used OEM DI manifold gaskets with a good gasket sealer just to be sure. Are you getting enough torque on the manifold bolts ?
When the rebuild was performed did the cylinder block have new liners fitted ? They can leak at the top surface , has the exhaust ports been opened up near any water jackets ? Was the cylinder head re machined so as to achieve a flat surface.
11-17-2009, 12:04 PM #8
Yes I am 100% sure it is water getting in front cyl as it runs on just one(rear) as soon as I put it in the water. When I take plugs out and turn engine over loads of water comes out of front plug hole. It's definately not the manifold gaskets as they have been renewed and sealed etc. Existing liners were reused, cannot see why not. I am going to check with a stock head on the weekend but my existing head looks good to me and was perfect before rebuild.
Whats the chances of machinist breaking through into water jacket when chamfering ports etc ?
11-18-2009, 04:55 AM #9
Something is way off in your set up , Can you describe the complete water routing including the 2nd cooling line.
Are you using the 8mm locating dowells in the head and cylinder base ? what about the Orings on the studs ? Are all the machined surfaces on the cylinder and head flat and smooth ? Have you run this with a stock pipe to verify that the pipes arn't the problem.Something is wrong big time just have to find it by elimination.
11-18-2009, 12:08 PM #10
Water routing is as follows.
2 x 1/2 inch lines in from pump, 1 to each exhaust manifold via extra water inlets. 1 of these lines splits with a T to a 8mm line to case cooler and then out the side via a 3/8 pisser. Water then flows through pipes via usual route with 2 x 1/2 inch pissers. Also water flows into motor via manifolds and out from cylinder head via another 1/2 inch pisser and out from case drain 8mm to pump. I think that is it from memory as the ski is at the lake and not at home.
All studs have new O rings, dowels are in place and new gaskets used throughout. Head is good, I assume top of cylinder is good too as it was fine before it came apart.
I have not ran the motor with the stock exhaust since rebuild, looking back maybe this was a mistake ? I will post a pic up of the setup so you can see for yourself.
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