Results 1 to 8 of 8

Thread: 97 GP1200

  1. #1

    97 GP1200

    I replaced my oil seals, replaced the bad coil and regulator too (just in case) and rebuilt my carbs (2nd time since I owned it). I got it started and was able to verify it is running on all three cylinders. 2 carbs are dribbing so I will yank them again and replace the springs with heavier ones (1.2 needle seats) in the spring. Too cold to work on it so I fogged, sealed it all up and sprayed her.
    I removed, cleaned and reset the low and high needles to the factory specs. Will adjust in spring but is there a way to easily adjust these???

    My craft is stock with the factory carbs, intake and cleaner. The only engine mods are bolson reeds, milled head by GroupK I believe (long time ago) and rebuilt cylinder twice by Yamaha due to a factory defect. My jets are stock and so is the CDI. I reset the needles to the fact specs and put the limiter caps on centered so I have a little adjustment. Thye are easy to yank off but with the air horn on how can you really adjust these things??

    Is there an extension I can buy so I could remove the limiter caps , slip the entension over it and then adjust the needles. That would allow me to make changes easily and actually get my hands on the needles to fine tune them.

    I suppose I could push some tubing over them and that would allow me to adjust from above the air horn. How does anyone else do this? I really don't want to buy little t handles since the problem is reaching them...no turning them.


  2. #2
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    I use the R&D Flame arrestor, it is slip on and does not require hose clamps. This allows me to easily remove and adjust the T-handles (I added the three high speed handles). My Carbs have 1.5 N&S stock, I am not sure when Yamaha Changed but some had 1.2's and other had 1.5 N&S in them. Mine were stock with the 60gram spring and I had dribbling issues, I went to 115 gram spring changed all the pilots jets to 100. I also doubled up on the little check valve under the jet cover block this eliminated the dribbling issue. I started with all screws set 1 turn out. The carbs had 95 pilot on #1, 97.5 on #3 and 100 on #2 stock. I did nothing with the top end Jets they are fine as is. These mods are fairly easy and inexpensive to do the T-handles are $7 ea. and the Jets $2.50 ea. The flame Arrestor was the only expensive item, I got mine with the adapters for $100

    The one other mod I do to these is the drilled return pressure balancing mod this adds life to the check valves in the fuel pump and ensure equal fuel pressure in all three carbs. You will need to add an inline return restrictor with a 105 jet in it for proper fuel pressure.

  3. #3

    Join Date
    Jun 2009
    Location
    Spartanburg,South Carolina
    Posts
    144
    I drilled my returns out but got the information from another old school post that listed using a 95 jet for restrictor,so is it the 95 or 105 as listed here for proper fuel pressure?

  4. #4
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    I have found 105 averages out better on the older style carbs. best method is to get a gauge and dial it in to 1-2 psi idle and 5-7 WOT

  5. #5
    I may change the stock intake to the Pro locks - I take it that it only needs a carb adapter that bolts to the carb and then the arrestor simply pops onto that - about $200 for the six pieces and another 30 for covers. It seems like the engine would be louder with the flame arrestors compared to the stock cover.

    I don't know what my pilots are but why did you change from the stock? I though the Gp1200 intake had very little air restrictions.

    I use the oil injection and want to keep it. I have no chokes but primers so I must have plugged the engine side hole. Can I simply put another primer fitting in there and hook new oil lines up to it? Should be about the right size fitting for the oil lines.

    I don't understand where you are drilling out the return lines so I will have to read up on that. Are you implying that if one carb pump failed the pressure from the others in the return line what keep gas flowing to the carb with the failed pump?

    Is the restrictor simply a carb pilot of that size placed into the line or are they restrictors made specificially for this purpose?

    Thanks

  6. +1 by:


  7. #6
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    I changed the pilots because I altered the Pop off pressure and wanted a little more pilot on the bottom end. Using the pre filters will richen up the carbs a bit.

    The drilled returns is drilling out the small restrictor hole in the carb body on the fuel pump side with 1/8" drill bit. The restrictor can be an inline fitting or installed in the last tee of the carbs, it is a main jet. on the GP carbs the tee's are small an inline works best, I tap a barbed 1/4" hose coupling with an M5 for this.

    The Pro-Loks take a special adapter from R&D you get them as a set. I have an extra set of adapters and a new Flame arrestor if you are looking to buy one.

    As for the Oil injection yes you can use the primer fittings for this same size 1/8" I have these also if you need them.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Carb 257.jpg 
Views:	365 
Size:	125.0 KB 
ID:	223103   Click image for larger version. 

Name:	Carb 115.jpg 
Views:	368 
Size:	84.0 KB 
ID:	223104  

  8. #7
    Quote Originally Posted by OsideBill View Post
    I changed the pilots because I altered the Pop off pressure and wanted a little more pilot on the bottom end. Using the pre filters will richen up the carbs a bit.

    The drilled returns is drilling out the small restrictor hole in the carb body on the fuel pump side with 1/8" drill bit. The restrictor can be an inline fitting or installed in the last tee of the carbs, it is a main jet. on the GP carbs the tee's are small an inline works best, I tap a barbed 1/4" hose coupling with an M5 for this.

    The Pro-Loks take a special adapter from R&D you get them as a set. I have an extra set of adapters and a new Flame arrestor if you are looking to buy one.

    As for the Oil injection yes you can use the primer fittings for this same size 1/8" I have these also if you need them.
    Bill

    I was waiting for a person to give me a price on a used a Pro lock but never heard back from him. Please give me a price for everything you can supply...ProLocks, flame arrestor, restrictor Ts (individual if you think that is best) , oil Ts, 100 pilot jets,and T handles (if you have them).
    I am going to re-pull the carbs in the spring. I had one or two dribblers still when I started it and tested in the driveway. Do you have 115 gram springs - although with 1.2 needles that may be too much...

  9. #8
    Moderator OsideBill's Avatar
    Join Date
    Mar 2006
    Location
    United States
    Posts
    11,875
    +1
    30
    One other I trick I do for dribbling carbs is covered in the Mikuni SBN manual, and that is doubling up on the check valve under the valve body assembly. That is the piece that covers the jets I usually use the old check valve on top of the new one I install when I rebuild them. The 115 gr spring will be too much for 1.2 N&S you may want to try an 80gr spring first.

    I will PM you pricing on the stuff.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. The history of my 97 GP1200 (long, possibly boring to some)
    By 97GPSLEEPER in forum Yamaha Old School Skis
    Replies: 15
    Last Post: 10-09-2008, 01:29 PM
  2. What mods should I do to my stock 97 GP1200..
    By 2lick in forum Yamaha Open Discussion
    Replies: 7
    Last Post: 02-11-2007, 08:28 PM
  3. My 97 Gp1200
    By 97GPSLEEPER in forum Videos & Pictures
    Replies: 10
    Last Post: 07-25-2006, 08:45 PM
  4. 97 Gp1200 hull crack's?
    By jy in forum Yamaha PWC Performance (2-stroke)
    Replies: 1
    Last Post: 07-09-2006, 11:50 AM
  5. I wanna run dual cooling on my 97 GP1200
    By SLOW65U in forum Yamaha Old School Skis
    Replies: 7
    Last Post: 12-14-2005, 01:58 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
  •