Page 1 of 4 1 2 3 ... LastLast
Results 1 to 10 of 33
  1. #1
    mibunkerking's Avatar
    Join Date
    Aug 2008
    Location
    Jax,Fl
    Posts
    2,260
    +1
    117

    questions about big bore

    i have searched for several days now about big boring my 951 x4 project. i can't seem to find a solid write up about what is involved anywhere on here or google. i have read bens sticky many times over as well as others but still can't find a basic step by step or breakdown. so i have some questions.

    1. what is involved in making a 1050?

    2. what can i expect to pay in parts and machining?

    3. will i need to resleave?

    4. i read somewhere that you can make a 1020/1017 for a little less gain and half the cost?

    5. and lastly, what is the best place to get parts and machining for a big bore?

    thanks for any help.


  2. #2

  3. #3
    Kidd800XP's Avatar
    Join Date
    Apr 2008
    Location
    Piedmont,Al
    Posts
    343
    Quote Originally Posted by mibunkerking View Post
    i have searched for several days now about big boring my 951 x4 project. i can't seem to find a solid write up about what is involved anywhere on here or google. i have read bens sticky many times over as well as others but still can't find a basic step by step or breakdown. so i have some questions.

    1. what is involved in making a 1050? Pistons,have head cut,clearence the raves. Theres more but those are the basics. I test fit my motor 3 times having machine work done and double checking everything

    2. what can i expect to pay in parts and machining? depends

    3. will i need to resleave? I would not for rec use and just built a 1017. The more you bore them out the thinner they get then they start cracking when they over heat and are to thin. So its kinda one of those things you will have to decide on.

    4. i read somewhere that you can make a 1020/1017 for a little less gain and half the cost? dont know about half but you can use 91.00 MM wisecos See my set up below

    5. and lastly, what is the best place to get parts and machining for a big bore? you can buy the pistons from wiseco or shop for a better deal. use cometic for head and base gasket or wiseco. Find a good machine shop near you and let them do it. The guy I use here local charges $ 40.00 per hole and I just tell him what clearance I want on the piston/sleeve

    thanks for any help.


    Here is what I have going in the rxx but I had it in a gsx last yr and rode it only has about 8 hrs on it. Started out with wisecos and made a 1017 and I have enough room for atleast 2 rebuilds on the top end with the larger sleeves

    Rebuilt crank with honda rods
    Oem rebuilt CB shaft from parker yamaha
    Wiseco big bore sleeves with 91.00 mm pistons
    Group K head mod cut to 1020 with the added cooling in the top
    Renaldi Reeds and spacers
    Mel Miller intake
    DI case cooler
    I use cometic for gaskets

    Hope that helps a bit

  4. #4
    mibunkerking's Avatar
    Join Date
    Aug 2008
    Location
    Jax,Fl
    Posts
    2,260
    +1
    117
    Quote Originally Posted by X-Runner View Post
    thanks for the link. i missed that thread

    Quote Originally Posted by Kidd800XP View Post
    Here is what I have going in the rxx but I had it in a gsx last yr and rode it only has about 8 hrs on it. Started out with wisecos and made a 1017 and I have enough room for atleast 2 rebuilds on the top end with the larger sleeves

    Rebuilt crank with honda rods
    Oem rebuilt CB shaft from parker yamaha
    Wiseco big bore sleeves with 91.00 mm pistons
    Group K head mod cut to 1020 with the added cooling in the top
    Renaldi Reeds and spacers
    Mel Miller intake
    DI case cooler
    I use cometic for gaskets

    Hope that helps a bit

    thanks for all the info. i will probably have group k cut my head.

    1020/91mm will probably be the way i go since the pistons seem to be alot easier to find.

    now on those 91mm pistons, everywhere i find them is says that crankcase cleanup is required. what does it mean?

  5. #5
    Kidd800XP's Avatar
    Join Date
    Apr 2008
    Location
    Piedmont,Al
    Posts
    343
    Quote Originally Posted by mibunkerking View Post
    now on those 91mm pistons, everywhere i find them is says that crankcase cleanup is required. what does it mean?

    It means since the piston is larger it will hit the crankcase if you dont remove some material for clearance. Here is a better trick though. Before you take your cylinder to be bored drop one of the pistons on the rod and see how much clearance you need and have it taken off the piston skirt so you dont have to work the cases and involves a lot less work. I used honda 139 MM rods and I had about 90 thousandths taken off the piston skirt. Havent had any problems with them. Just make sure your piston/cylinder clearance is set right and give a good warm up with those wisecos as they will cold seizure on you. One other smart investment is a hot tach.

  6. #6
    mibunkerking's Avatar
    Join Date
    Aug 2008
    Location
    Jax,Fl
    Posts
    2,260
    +1
    117
    how much of a difference in performance and topend did you see with your step up over stock Kidd? did you have to repitch your prop?

  7. #7
    WICKEDSEADOO's Avatar
    Join Date
    Jun 2009
    Location
    SO CAL
    Posts
    777
    +1
    76
    To give you an idea of top speed, my big bore stroker will do 74-75 mph

  8. #8
    mibunkerking's Avatar
    Join Date
    Aug 2008
    Location
    Jax,Fl
    Posts
    2,260
    +1
    117
    nice!!! i will be happy with 70. not sure if i want to go as far as strokeing it. i want this thing to beat a stock rxpx. (wishfull thinking) couple more questions i have.

    1. will i need a reprogrammed mpem or revlimiter module? like a micro touch?

    2. i know that miller heads are considered to be the best, but seeing as they are not the easiest things to find, what other heads will work with a 1020? r&d? ada? recut stock? any others?

    3. what size domes should i run with this setup on pump gas (92)? and squish?

    4. do i need to do anykind of porting for the 1020?

    5. jetting, in bens thread he says that a slight jetting increase is need for the big bore but he does not say how much. so what n/s, hi's, and lo's do i need? (will be getting prok F/A's)

    i think thats all for now. thanks again

  9. #9
    Kidd800XP's Avatar
    Join Date
    Apr 2008
    Location
    Piedmont,Al
    Posts
    343
    1. will i need a reprogrammed mpem or revlimiter module? like a micro touch?

    Not unless your going to aftermarket pipe

    2. i know that miller heads are considered to be the best, but seeing as they are not the easiest things to find, what other heads will work with a 1020? r&d? ada? recut stock? any others?

    Any will work if you have the domes opened up. Stock is good and cheaper



    3. what size domes should i run with this setup on pump gas (92)? and squish?

    I would not go smaller then 49CC and your squish is going to depend on the head you use.


    4. do i need to do any kind of porting for the 1020?

    I dont have any porting on mine as of right now but will be doing some next winter I think.



    5. jetting, in bens thread he says that a slight jetting increase is need for the big bore but he does not say how much. so what n/s, hi's, and lo's do i need? (will be getting prok F/A's)

    Acc pump working or disconnected?




    Yes there was a difference. I installed a set of renaldi reeds and spacers with a miller intake the was cut to 1 in thick. I was running a 13/19 dyna fly with 85mm exit nozzle and a brass pump that was robbing MPH

  10. #10
    Kidd800XP's Avatar
    Join Date
    Apr 2008
    Location
    Piedmont,Al
    Posts
    343
    Quote Originally Posted by WICKEDSEADOO View Post
    To give you an idea of top speed, my big bore stroker will do 74-75 mph

    I hope I can get that from my rxx

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. QUESTION, 800R big bore cyls....
    By john zigler in forum Yamaha PWC Performance (2-stroke)
    Replies: 6
    Last Post: 12-07-2008, 08:31 PM
  2. cylinder question gp1200r big bore
    By spyder3000gtvr4 in forum Yamaha Open Discussion
    Replies: 11
    Last Post: 09-18-2007, 11:59 PM
  3. big bore questions
    By bow tie klr in forum Yamaha PWC Performance (2-stroke)
    Replies: 5
    Last Post: 09-14-2006, 03:11 PM
  4. Big Bore questions
    By MTRHEAD in forum Yamaha PWC Performance (2-stroke)
    Replies: 18
    Last Post: 07-21-2006, 08:44 PM
  5. big bore question?
    By leojr04 in forum Yamaha PWC Performance (2-stroke)
    Replies: 1
    Last Post: 04-28-2006, 10:59 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
  •