Yamaha GP1200R - Engine Power Lost

[bstoppelmoor]

I installed a Yamaha GP1200R motor last December and now have top end power lost & engine mis after 41 hours. Cylinder #1, compression is 116#, Cylinder #2 & #3 compression is 110#. The first cylinder is running lean, 2 & 3 are burning rich and the engine has a steady mis. When the engine was running great it would max at 63mpg and now I'm lucky to get it up to 50mpg. I've check the carbs, powervalves linkage everything seems to check out fine. I'm not sure were to look next! Any suggestions would be great!

Thanks,

[Relentless1]

Re: Yamaha GP1200R - Engine Power Lost

Have you removed the carbs and taken them totally apart, both sides? have you cleaned the internal filters inside the carbs?

[glenozzy]

Re: Yamaha GP1200R - Engine Power Lost

check PV motor, after you turn off the motor look to see the PV motor cycle about 10 seconds after.

[anapg77]

Re: Yamaha GP1200R - Engine Power Lost

Check the cat. convertor to make sure it isn't in pieces.

[waverider]

Re: Yamaha GP1200R - Engine Power Lost

I would remove the head,,,it will tell all (or most)...your pv motor may be moving and the PV coupling/shaft turning and the PV shafts may be moving in and out..but the PV shaft could be broken from the Valve itself...only way to confirm is pull the head or remove the PV cover and pull out the PV all the way and verify it is not broken...if you just pull the PV out and it is OK you will still be wondering what else is wrong and eventually have to pull the head...If you purchased the engine from SBT and it is still under warranty you can not remove the head,,,it will void the warranty..

[bstoppelmoor]

Re: Yamaha GP1200R - Engine Power Lost

I have checked the PV movement it seem to be working. I removed the cat and installed a D-Plate after the installation of the new engine which is nice. I'm going to pull the carbs and do a rebuild to see if this helps since the carbs are the original on the engine.Thanks for the input. :)

[Relentless1]

Re: Yamaha GP1200R - Engine Power Lost

On the opposite side of the carbs then the diaphram, jets and N&S, open it up.

Look for a circle looking rubber thing. Grab it and pull it out. You will see it is a barrel filter.It is the internal filter on the carbs.

I be money you find them almost completely clogged with a hair looking furr ball.

This is the cause of many, many PWC problems.

[waverider]

Re: Yamaha GP1200R - Engine Power Lost

How did you confirm the PV movement??? Did you remove the PV covers and verify the valve is moving in and out Did you remove the whole PV or just observe the head of the shaft moving...If the Shaft and the Valve body are seperated then the valve is just sitting there waiting to drop onto the piston top or rub against the side of the piston when it drops:emoticonr ....It is a time bomb waiting to go off if you do not verify the PV (PV's) is intact...

[bstoppelmoor]

Re: Yamaha GP1200R - Engine Power Lost/Defective Power Valves

Yep, defective power valves and poor workmanship plus missing compotents on the cylinder heads. Who would of guess on a rebuilt motor from SBT with less than 50 hrs that you would be replacing the whole engine again. The power vavles dropped down into the 3rd cylinder and blew a whole into the piston and the middle cylinder is also damaged as well. I'm taking a hard look at other Yamaha engine builders for sure. I don't enjoy dropping in a new engine every year do to defective parts from SBT. Plus the techicians at SBT can not trouble shoot worth crab they are as worthless as their crabby engines with high prices.......................! What makes this situation bad is that SBT was aware of their defective power valves at the time and did nothing.

So just a note: Save your money and purchase from another vendor who can provide better service, high quality parts and experienced technicial support.

Not a great summer!:emoticonr

[Technical Support]

Re: Yamaha GP1200R - Engine Power Lost

Please give me the serial number of your engine and I will be happy to look into your case.

Our powervalves are new and have no issues. It is physically impossible for them to contact the pistons, they are larger than the exhaust port.

Given that you have destroyed 3 engines (or more?) in a row after relatively short lives, perhaps you have not yet corrected the original problem(s) with your ski, or are operating/maintaining it improperly?

[Phil STX15F]

Re: Yamaha GP1200R - Engine Power Lost

It sounds like you just keep replacing the motor without finding the root cause for your oem motor failure. Then you post that you have "Checked" the carbs, what does that mean, you looked at them from the outside and they looked ok? When your first motor failed did you repair anything? Doesn't sound like it! If you do not fix the problem that took out your OEM motor first, then you can build the best of the best motor and it would still fail do to your bad external componants such as plugged up carbs, fuel tank baffle, or something as simple as the wrong plugs.

[bstoppelmoor]

Re: Yamaha GP1200R - Engine Power Lost

The first engine from the factory blew after 175 hrs do to poor detonation and overheating problem from the cat breaking into pieces plugging the exhaust pipe which was replaced by a "D-Plate" and Chip before the new engine was installed. I also replaced the impeller/intake grade,ride plate and wear ring and rebuilt the carbs and set them to factory settings. Plug No. BRES-11 were replaced every 25 hrs and gapped to 0.039-0.043 as specified in the maintenance book and I also checked and tightened any lose bolts. The fuel filter was changed twice a year along with the full point inspection of the control system, oil injection system, power unit, electrical, jet pump unit and the general lubrication points. My engine was winterized and covered every year and placed in a heated garage.

The second engine was purchased through SBT Part No. 40-407, SBT Serial No. 45586, Date of Purchase: 12/14/04, Invoice: 425327 for a total cost of $1,694.00. This engine didn't even make the 50 hr mark before loss of power due to the reduction of compression in #2 and #3 cylinders which I stated earlier in my post and to your technicians. I talked to one of your tech's and he suggested that I rebuild and retune my carbs because I had a lean condition causing my loss of power. However, I have the pics that can prove the Power valve assembly in #3 cylinder is completely missing and #3 piston has a hole through it on the same side the power valve assembly is located, plus the #2 cylinder is just as bad.

The third engine is still pending do to finding the next best quality engine builder for the 2001-GP1200R-Yamaha.

Please give me the serial number of your engine and I will be happy to look into your case.

Our powervalves are new and have no issues. It is physically impossible for them to contact the pistons, they are larger than the exhaust port.

Given that you have destroyed 3 engines (or more?) in a row after relatively short lives, perhaps you have not yet corrected the original problem(s) with your ski, or are operating/maintaining it improperly?

[bstoppelmoor]

Re: Yamaha GP1200R - Engine Power Lost

Yep, you sound like another won a be tech who know's nothing about engines, and I'm not impressed. I'm a full-time mechanic who races 1/4 mile drag, plus yamaha boats since I was 15. I bet you haven't even changed a plug on your own boat let alone work on your own car engine.

I maintain all my own engines and I have replaced the following items on my GP1200R to eliminate any problems from the first OEM engine.


1. "D-Plate" and Chip
2. Solas Impeller YF-CD-13/19
3. Top Loader Intake grade RY22420
4. Ride plate RY21020
5. Wear Ring 66V-51312-01-94
6. Pump Seal RY2520
7. Rebuilt the carbs with SBN-I Kit No. 66V-W0093-01-00 and set them to factory settings, plus replaced the Mikuni internal fuel filter S/BN 130109
8. Plug No. BRES-11 were replaced every 25 hrs and gapped to 0.039-0.043 as specified
9. Fuel Filter 66V-24560-00-00 and oil filter was changed twice a year
10. A full point inspection of the control system, oil injection system, power unit, electrical, jet pump unit and the general lubrication of points done every 25 hrs.

If you have any great suggestions please be so generous and share your wealth of information to all of us Yamaha owners.

Oh, by the way I'm a 47 yr old female mechanic who could out build and out run anything you have on your Kawasaki ****!!!!!!

It sounds like you just keep replacing the motor without finding the root cause for your oem motor failure. Then you post that you have "Checked" the carbs, what does that mean, you looked at them from the outside and they looked ok? When your first motor failed did you repair anything? Doesn't sound like it! If you do not fix the problem that took out your OEM motor first, then you can build the best of the best motor and it would still fail do to your bad external componants such as plugged up carbs, fuel tank baffle, or something as simple as the wrong plugs.

[bstoppelmoor]

Re: Yamaha GP1200R - Engine Power Lost

Defective Power valves for sure. The power valve blew through the #3 piston and #2 piston is just as bad. SBT tech didn't believe the power valve problem and believed it to be a lean condition from the carb's. I rebuilt/retuned the carb's and the problem still was not corrected. The pics tell it all.:emoticonr

How did you confirm the PV movement??? Did you remove the PV covers and verify the valve is moving in and out Did you remove the whole PV or just observe the head of the shaft moving...If the Shaft and the Valve body are seperated then the valve is just sitting there waiting to drop onto the piston top or rub against the side of the piston when it drops:emoticonr ....It is a time bomb waiting to go off if you do not verify the PV (PV's) is intact...

[Technical Support]

Re: Yamaha GP1200R - Engine Power Lost

Given the original purchase was over 2 years ago, I verified with the Warranty Dept. that no coverage is going to be extended. Our assesment of lean seizure damage is based on the condition of the engine as it was returned to us, and is our best educated opionion given the facts we have to work with.

If you had a whole power vavle assembly missing, you had some serious damage and debris going through there to take it out. If it happened again, you obviously have not fully corrected your problems. We stand by our recommendations to you, and by all means please go to another source of parts and help from here on out, good luck.