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  1. #1

    800 yam engin mods

    How far can you safely go with one of these motors? For eg, (I only know seadoo really) my 1050 xp with novis, Coffmans, Franco ignition, etc etc running 50/50 av gas and unleaded is safe and fast, and very reliable. What's the best things to do on the 800 yam? It's for racing but I want it to last a season atleast between rebuilds.


    I got plans for handling mods, it's just the motor I'm unsure which direction to go with.

    I was thinking...
    1300r cylinders,
    novi 48's,
    aftermarket ecu,
    some kind of single pipe (??)
    aftermarket reeds.

    I don't know, you tell me! Haven't got the motor yet just a wb800 hull. Need motor pump and all electrics to complete. I considered my 1050 seadoo engine but not sure, I also considered a 785 seadoo engine or sxr engine, as their maybe more tuneable?? But ideally I guess the yam 66e 800 is best way to go.

    I dont want to go down the twin pipe route, or the 972. Id consider a 1200r engine?? At this stage its all just thoughts and ideas, any help greatly appreaciated


  2. #2
    mudslanger's Avatar
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    You should do some more research on the 1200R motor and punching it out to 1390. Or even one of the supercharged engines for race proposes. It all comes down to how fast you want to go and what kind of racing your wanting to do.

  3. #3
    Quote Originally Posted by mudslanger View Post
    You should do some more research on the 1200R motor and punching it out to 1390. Or even one of the supercharged engines for race proposes. It all comes down to how fast you want to go and what kind of racing your wanting to do.
    Its to race in the sports class, theres a cc limit of 1200 so cant go over that. Im pretty sure Im going to be running the 800 motor with 1300r cylinders, or maybe even stock cylinders. Id love a single pipe. Im new to yams really and I just need pointing in the right direction

  4. #4
    Almost's Avatar
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    Quote Originally Posted by 1ig4eva View Post
    Quote Originally Posted by mudslanger View Post
    You should do some more research on the 1200R motor and punching it out to 1390. Or even one of the supercharged engines for race proposes. It all comes down to how fast you want to go and what kind of racing your wanting to do.
    Its to race in the sports class, theres a cc limit of 1200 so cant go over that. Im pretty sure Im going to be running the 800 motor with 1300r cylinders, or maybe even stock cylinders. Id love a single pipe. Im new to yams really and I just need pointing in the right direction
    Don't know if you will see any gains, I think last time it was brought up on this forum it came to the conclusion that 800 cylinders have more aggressive porting then 12/300r cylinders to make up for the smaller motor, so swapping them won't give you the gain you are looking for.

    I do think you will be better off going with a non pv 1200 cc motor. No matter how much money you put in to an 800cc motor you will never be as fast.

  5. #5
    800 cylinders are more power

  6. #6
    Quote Originally Posted by Almost View Post
    Quote Originally Posted by 1ig4eva View Post
    Quote Originally Posted by mudslanger View Post
    You should do some more research on the 1200R motor and punching it out to 1390. Or even one of the supercharged engines for race proposes. It all comes down to how fast you want to go and what kind of racing your wanting to do.
    Its to race in the sports class, theres a cc limit of 1200 so cant go over that. Im pretty sure Im going to be running the 800 motor with 1300r cylinders, or maybe even stock cylinders. Id love a single pipe. Im new to yams really and I just need pointing in the right direction
    Don't know if you will see any gains, I think last time it was brought up on this forum it came to the conclusion that 800 cylinders have more aggressive porting then 12/300r cylinders to make up for the smaller motor, so swapping them won't give you the gain you are looking for.

    I do think you will be better off going with a non pv 1200 cc motor. No matter how much money you put in to an 800cc motor you will never be as fast.

    May I ask why the non pv motor?? May be a stupid question but I'm learning.

    So how much work would it be do you guys think, 1200 motor in wb800? I'm thinking of mounts, exhaust fitment, drive shaft and pump?

  7. #7
    Almost's Avatar
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    Quote Originally Posted by 1ig4eva View Post
    Quote Originally Posted by Almost View Post
    Quote Originally Posted by 1ig4eva View Post
    Quote Originally Posted by mudslanger View Post
    You should do some more research on the 1200R motor and punching it out to 1390. Or even one of the supercharged engines for race proposes. It all comes down to how fast you want to go and what kind of racing your wanting to do.
    Its to race in the sports class, theres a cc limit of 1200 so cant go over that. Im pretty sure Im going to be running the 800 motor with 1300r cylinders, or maybe even stock cylinders. Id love a single pipe. Im new to yams really and I just need pointing in the right direction
    Don't know if you will see any gains, I think last time it was brought up on this forum it came to the conclusion that 800 cylinders have more aggressive porting then 12/300r cylinders to make up for the smaller motor, so swapping them won't give you the gain you are looking for.

    I do think you will be better off going with a non pv 1200 cc motor. No matter how much money you put in to an 800cc motor you will never be as fast.

    May I ask why the non pv motor?? May be a stupid question but I'm learning.

    So how much work would it be do you guys think, 1200 motor in wb800? I'm thinking of mounts, exhaust fitment, drive shaft and pump?
    It's smaller, I doubt you will fit a 66v out of a GPR in there with the ridiculous exhaust. The older non pv 1200's from the GP have smaller exhaust set up and are more reliable.

  8. #8
    Quote Originally Posted by Almost View Post
    Quote Originally Posted by 1ig4eva View Post
    Quote Originally Posted by Almost View Post
    Quote Originally Posted by 1ig4eva View Post
    Quote Originally Posted by mudslanger View Post
    You should do some more research on the 1200R motor and punching it out to 1390. Or even one of the supercharged engines for race proposes. It all comes down to how fast you want to go and what kind of racing your wanting to do.
    Its to race in the sports class, theres a cc limit of 1200 so cant go over that. Im pretty sure Im going to be running the 800 motor with 1300r cylinders, or maybe even stock cylinders. Id love a single pipe. Im new to yams really and I just need pointing in the right direction
    Don't know if you will see any gains, I think last time it was brought up on this forum it came to the conclusion that 800 cylinders have more aggressive porting then 12/300r cylinders to make up for the smaller motor, so swapping them won't give you the gain you are looking for.

    I do think you will be better off going with a non pv 1200 cc motor. No matter how much money you put in to an 800cc motor you will never be as fast.

    May I ask why the non pv motor?? May be a stupid question but I'm learning.

    So how much work would it be do you guys think, 1200 motor in wb800? I'm thinking of mounts, exhaust fitment, drive shaft and pump?
    It's smaller, I doubt you will fit a 66v out of a GPR in there with the ridiculous exhaust. The older non pv 1200's from the GP have smaller exhaust set up and are more reliable.

    Never knew that!! Great advice thanks. So I'll look about for an old gp1200 that someone's breaking or if I'm lucky a 1200 motor for sale. What do they call this motor, eg 800 is 66e 1200r 66v etc

  9. #9
    i know the 1200 and 800 motors have different motor mount placements. Your gonna have to cut into the hull and change locations and mount plate sizes. Im going this now with 2 xlts's. 800 mount converting it into 1200 locations.

  10. #10
    ...there are tons of used pipes for 650-760 non pv yami motors out there but for some reason not the 800. IMO I too agree it's a good idea to go with the non pv 1200 because it's the biggest bang for the buck. Finding an old one with a bad crank or piston or just a bad hull would be a good find, then just swapping out all the electronica seems the easiest route to go. But then again you might be tempted to put fpp triples since you're going through the process of changing the electronics, to some extent anyway... .

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