Results 1 to 5 of 5
  1. #1
    elmatta's Avatar
    Join Date
    Sep 2011
    Location
    CT
    Posts
    311
    +1
    8

    Compression, carbs, power valve gear wheel questions

    I bought a 01' gpr last month that i've been gathering mods and cleaning up for the spring. I believe the ski has the pro-tec 'wake up' kit. I've got the ride plate, intake, air filters, not sure about the impeller, riva stinger 2 and I think it has the head. First thing I checked was compression: mag 135-135-125 pto. I was going to wait for a head gasket before I took the head apart to check for scores or maybe valve damage on the rings. I noticed a choke hole wasn't plugged on the same PTO side. Would this cause a lower compression?


    While installing waveeaters I felt a bit of play on the gear (none of the couplers move, just the gear). Do I need to tighten the cables or should I remove the gear and maybe replace it? Problem was found before waveeaters and I thought they would help but didn't get fixed after the upgraded couplers.

    So after procrastinating about the other problems, I decided to rebuild the carbs. I noticed it still had stock jettings with the FA's so I put in new gaskets and tried to test for the pop off but Im not able to build any pressure. I put a bit of water around the gaskets and it looks like all the bolt holes and edges of the check valve gaskets are bubbling like crazy. I called hulk to try to tighten those damn screws but its still leaking. I must admit, I did buy the cheap winderosa rebuild. Are they really that bad or am I missing something?

    Below are the areas that its leaking. in yellow. I followed the manual for the correct placement for the gaskets and diaphragms. Also, there looks to be a diaphragm behind the pulse nipple; am I replacing that and using #3 and #4 in the diagram?

    Click image for larger version. 

Name:	carbleak.JPG 
Views:	138 
Size:	85.7 KB 
ID:	290708


  2. #2
    elmatta's Avatar
    Join Date
    Sep 2011
    Location
    CT
    Posts
    311
    +1
    8
    Ive got another problem. It looks like the previous owner possibly drilled too much into the low speed adjuster on the PTO carb and there still seems to still be another brass chunk 1/4-1/8 further down into the hole. Is that the stock adjuster and can I drill and tap that out?

  3. #3
    elmatta's Avatar
    Join Date
    Sep 2011
    Location
    CT
    Posts
    311
    +1
    8
    Im not going to worry too much about the power valve because its sturdy and dont think its going to fall in or hit the piston.

    I plugged the carb choke hole with a hex plug.

    I found out i was bridging the inlet to the outlet carbs instead of just capping them which caused air to leak out the wrong area.

    I removed the top end and everything looks brand new, head looked like it was barely used, walls were smoother then a babies butt, no scratches whats so ever besides the crass hatches which are still clearly visible. End of valve looks flawless. What else could cause a slight drop in psi? Rings?
    Click image for larger version. 

Name:	IMAG1278.jpg 
Views:	69 
Size:	100.2 KB 
ID:	290971 Click image for larger version. 

Name:	IMAG1285.jpg 
Views:	71 
Size:	70.3 KB 
ID:	290970
    Last edited by elmatta; 01-25-2013 at 05:26 AM.

  4. #4

    Join Date
    Aug 2006
    Location
    Indiana
    Posts
    1,274
    +1
    81
    Quote Originally Posted by elmatta View Post
    Im not going to worry too much about the power valve because its sturdy and dont think its going to fall in or hit the piston.

    I plugged the carb choke hole with a hex plug.

    I found out i was bridging the inlet to the outlet carbs instead of just capping them which caused air to leak out the wrong area.

    What else could cause a slight drop in psi? Rings?
    Click image for larger version. 

Name:	IMAG1278.jpg 
Views:	69 
Size:	100.2 KB 
ID:	290971 Click image for larger version. 

Name:	IMAG1285.jpg 
Views:	71 
Size:	70.3 KB 
ID:	290970
    Bridging the carb inlet/outlets is fine as that should not effect leakage, as there is pressure on both sides when running. If you have leaks, then you have leaks and need to fix them. It is preferred to supply the air into the inlet to reduce chances of damaging the fuel pump diaphram, but bridging the other inlet to the outlet, or plugging, either does the same thing. You have the whole pump pressurized and if you are leaking air out of those areas you listed you need to tighten the screws or replace the gaskets. I would not be over concerned about 10 psi difference if the cyl looks good. It looks a bit like a fresh rebuild as the heads are so clean. If so maybe the rings are not completely seated yet. You could always change the rings in that cyl while you have it apart.

  5. #5
    elmatta's Avatar
    Join Date
    Sep 2011
    Location
    CT
    Posts
    311
    +1
    8
    I bought 2 sets of rings for that cylinder and I plan on replacing them since I already have it apart. The ski only has 70hrs but the wash and the cylinder heads look like it has less. I believe the pro-tec mods were put on very recently. Judging by the 3ft of snow I Just got, I dont think i'll be able to break the rings in for a while.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. GP1200 (non power valve) carb question
    By mindless in forum Yamaha PWC Performance (2-stroke)
    Replies: 1
    Last Post: 05-09-2013, 10:48 PM
  2. Power valves and couplers question
    By turbo94supra in forum Yamaha PWC Performance (2-stroke)
    Replies: 4
    Last Post: 02-01-2013, 06:54 PM
  3. questions about power valve?
    By stingray152003 in forum Yamaha Open Discussion
    Replies: 8
    Last Post: 12-18-2008, 03:35 PM
  4. Power valves / clips / other pre-purchase questions
    By sleeper_dave in forum Yamaha PWC Performance (2-stroke)
    Replies: 20
    Last Post: 06-19-2008, 08:27 PM
  5. quick power valve question..gp1200r 2000
    By Hydrotherapy in forum Yamaha PWC Performance (2-stroke)
    Replies: 14
    Last Post: 07-28-2007, 02:21 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •