Page 1 of 4 1 2 3 ... LastLast
Results 1 to 10 of 34
  1. #1
    spdracr's Avatar
    Join Date
    Sep 2005
    Location
    Fort Lauderdale
    Posts
    422
    +1
    2

    Questions about porting vs. BB

    I have my cylinders off and I was getting ready to send them to Lowell Horning. When I talked to Lowell today I was going to only have him only port my 1200 cylinders but now I think I may have them ported and go 1300. My questions are:


    1. Do I use Riva gas valves or the OEM mechanical valves?

    2. How much top speed will I see? 1200 ported vs. 1300 ported

    3. Is it worth the trouble and extra money? 1300 resleave.

    4. 84 mm from Lowell, 86 mm from Riva, or the 87mm from Group K?

    Please let me know what you think cause I can't make up my mind!


  2. #2
    Hydrotoys's Avatar
    Join Date
    Jul 2005
    Location
    Mesa, AZ
    Posts
    16,712
    +1
    85
    BE VERY SPECIFIC ON WHAT QUALITY GASOLINE YOU ARE GOING TO USE!!! The more I hear of porting, the more I hear the term race gas, or 95 octane or a bunch of other terms not related to pump gas.

    Insandiego Joe can get you a good deal on 84mm pistons. You could go 84mm ported, and gain roughly 2-5mph and monster acceleration. The gas valves are nice, and eliminate tuning issues and reliability issues with the stock system.

    I think the Group K system is pretty much plug and play, and is made for 91. I'd imagine those big slugs would have tons of acceleration, but I don't like loosing my power valves.

  3. #3
    spdracr's Avatar
    Join Date
    Sep 2005
    Location
    Fort Lauderdale
    Posts
    422
    +1
    2
    I want to use 93 octane. I really only want to do this once but I know that
    things can go wrong and I will be back in there again. I like the idea of 84mm pistons cause they are easier to get than waiting for groupk to send me some at 150 each plus 450 to fix a cylinder. I also don't like loosing the power valves. Riva's 86 mm pistons are 200 bucks each!

    Right now I'm leaning towards Lowell and a 1200 to 1300 conversion.

    Thanks for for help Mark!

  4. #4
    ramnj's Avatar
    Join Date
    Apr 2005
    Location
    New Jersey
    Posts
    1,713
    spdracr,

    What was the outcome and how did it go?

  5. #5
    Moderator Insanediego Joe's Avatar
    Join Date
    Mar 2006
    Location
    San Diego, California, United States
    Posts
    5,885
    +1
    142
    if group k is selling big bore piston kits at 150 bucs. JUMP all over that deal cause that is unheard of pricing.

  6. #6
    Pistonwash's Avatar
    Join Date
    Aug 2005
    Location
    Florida
    Posts
    3,595
    +1
    77
    1. Do I use Riva gas valves or the OEM mechanical valves?

    I have the gas valves right now, I may switch back to pv's...jury still out on which one I like best. They are both good, the gas valves jump out of the whole a little quicker.

    2. How much top speed will I see? 1200 ported vs. 1300 ported

    Probably 2-4 mph depending upon set-up. There are some 1200's that hitting 80mph (triple-piped), it will cost about $1,500 for the BB upgrade and porting.

    3. Is it worth the trouble and extra money? 1300 resleave.

    No, to the re-sleeve, get it re-nicked if you're gonna go BB.

    4. 84 mm from Lowell, 86 mm from Riva, or the 87mm from Group K?

    84mm from Lowell...period.

    Please let me know what you think cause I can't make up my mind!

  7. #7
    Hydrotoys's Avatar
    Join Date
    Jul 2005
    Location
    Mesa, AZ
    Posts
    16,712
    +1
    85
    Why not 87 from Lowell?

  8. #8
    Pistonwash's Avatar
    Join Date
    Aug 2005
    Location
    Florida
    Posts
    3,595
    +1
    77
    Quote Originally Posted by hydrotoys
    Why not 87 from Lowell?
    Another possiblity..I am a little worried about the extra ponies in the single, we'll see how they will stand up. We are at a crossroads right now with my triple going to 87mm...dunno, Lowell's got some homework to do. Not sure how the pipes are gonna react, thats why I was wanting your FP waterbox.

  9. #9
    Hydrotoys's Avatar
    Join Date
    Jul 2005
    Location
    Mesa, AZ
    Posts
    16,712
    +1
    85
    You'd be better off running the 87mm on the pipes now. The RPM range isn't going to change... the stroke isn't changing.

    You also can not install the FP exhaust without cutting a four inch hole in your hull. After that, it's not a pretty sight to make it work with the original exhaust... and PW, you would be the only person to know how I already know that! THINK ABOUT IT.

    The exhaust is not your problem. The stock exhaust is massive and totally un-needed It's the stinger sizes in the triple pipes that may be an issue.

    If fact the single piper might work BETTER (speed to power) than the triple pipe 87mm due to the fact that the single pipe can be opened up at the D-plate more!!! Hmmm, wonder if anyone has tried that on a 84mm yet?

  10. #10
    Pistonwash's Avatar
    Join Date
    Aug 2005
    Location
    Florida
    Posts
    3,595
    +1
    77
    If fact the single piper might work BETTER (speed to power) than the triple pipe 87mm due to the fact that the single pipe can be opened up at the D-plate more!!! Hmmm, wonder if anyone has tried that on a 84mm yet?
    Yes, they have.

    Knowing specific perimeters is the key though.

    The trapped volume of the triples worries me, not sure what the back pressure will do with the extra gulp of expended exhaust.

    Another tip for the "inch" hunters...the 1300 waterbox is better.

    That is all.

Page 1 of 4 1 2 3 ... LastLast

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Replies: 7
    Last Post: 07-25-2014, 11:20 PM
  2. Question about roller vs bunk
    By CajunJosh in forum Towing and Trailers
    Replies: 6
    Last Post: 11-01-2013, 06:37 PM
  3. Question about ride quality of XP vs. GSX
    By Quad411 in forum 2-Stroke Performance
    Replies: 19
    Last Post: 09-13-2008, 05:27 PM
  4. New to Wave Runners. Question about Sea Doo vs. yamaha
    By alias3r in forum 4-Tec Performance
    Replies: 38
    Last Post: 03-25-2008, 10:13 PM
  5. question about gas in gpr vs. rxp
    By stingray152003 in forum Yamaha Open Discussion
    Replies: 5
    Last Post: 09-14-2007, 04:36 PM

Posting Permissions

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