06-01-2014, 10:27 AM #1
'03 GPR Rebuilt after grenading. What to check before running new motor...
I bought an '03 GP1300R "project" just a few months ago. I've been working on my own sleds, bikes and quads for years, but have never had my hands in a pwc and wanted to start.
Here's what happened with it. The guy I bought it from had bought it blown up from his brother... He took it to a local independent shop to have it rebuilt. They replaced the #1 and 3 cylinders along with all 3 pistons. From what I could tell that was all they did.
From what he said, he got through the break-in period + 1/2 hour of more aggressive riding and it blew apart again. When I got it I pulled the motor, the #3 piston was trash along with the new cylinder and big end rod bearing which smashed into the case and was not repairable. The #1 piston showed signs of detonation all over the crown... Cylinder was ok. #2 piston and cylinder were totally fine.
What I've done... Bought a nice, low hour bottom end. Split the cases, inspected the crank, cleaned all threads and reassembled. Deglazed #1 and 2 cylinders, replaced all pistons and wp bearings. Cylinders and pistons all measured and are within clearance spec. The motor is done and ready to install.
My question... After failing on the same cylinders twice in such a short time, what should I check? Injectors, ignition?
I'm guessing when this was rebuilt the top end was removed.. New top end slapped on and taken to the lake without any crank inspection or leak-down test. I'll be checking piston wash frequently for the first few hours... But if I need to have the injectors inspected and cleaned I'd rather do it now before everything goes back together.
Any input is greatly appreciated!
Last edited by blackedout96; 06-02-2014 at 10:00 AM.
06-01-2014, 07:52 PM #2
06-02-2014, 04:48 PM #3
06-02-2014, 06:45 PM #4
My thoughts exactly... He said the place was out of business by the time he went back.
Pressure tested good by service manual specs. Going to send the injectors out to get flow tested and cleaned. Can't really think of anything further to check.
06-19-2014, 11:09 AM #5
Well, I got everything back together and sounds great on the hose... Took a quick peek with my borescope and found some sort of black spots on the pistons after running. I was able to get some out through the spark plug hole and it doesn't appear to be metallic. Kind of just wipes away. Could this be old carbon getting sucked in from the exhaust?
What all I did...
-Cleaned Crank and cases
-all new pistons
-two cylinders deglazed and one replated
-injectors flow tested and cleaned
-new oem reeds
-pressure tested... held 10psi for 20 minutes without drop.
-removed old oil and gas
-replaced all oil lines
I can't imagine where it could be coming from aside from the exhaust... unless I had some 1211 squeeze out from between the cases.
06-19-2014, 04:41 PM #6
Do you have the test kit hooked up with the reed spacer plate on there as well? Those tend to leak somtimes and if you made your own kit to test the motor with that part off then it could still leak. Otherwise it sounds like you have everything covered. Again I know very little about the injection system. Is there some sort of fuel pressure test??
Also #1 cylinder looks like it may have some scoring on the 4 corners. I have read somewhere that means its the wrong size or something like that. Do you have OEM sized pistons? Some of those depend on the number stamped on the jug to tell what size OEM piston to order. Just a though out loud, does that ring a bell for anyone?
06-19-2014, 07:56 PM #7
Yeah I used the test kit with the throttle body boot plugs... The reeds, spacers and all were installed for the test.
06-19-2014, 09:10 PM #8
06-19-2014, 10:16 PM #9
06-20-2014, 06:59 AM #10
Does the damage pictured above look like anything that could have been caused by sucking in water? I ask because I found a small leak in the plastic water manifold that bolts to the exhaust.
The previous owner said his rebuild lasted through the break-in period and when he started to feed some speed to it is when it came apart. Wondering if it was continuously filling with water and when he hammered it, sucked water in and popped it.
Sorry to drag this thread out... just frustrating to have been through every possible cause of engine failure and come up with no conclusive evidence as to why it failed. The motor already being apart when I got it and not being able to pressure test before disassembly is very unfortunate.
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