Results 1 to 8 of 8
  1. #1
    Haven't fallen yet. MJE's Avatar
    Join Date
    May 2007
    Buzzards Bay, Massachusetts

    GP1800 from hell, what parts do I buy?

    So as much as I absolutely love Yamaha...I do have 1 machine that has been the absolute worst experience of my life. I will still buy Yamaha etc...but yeah, not getting too deep into it. "3rd motor", 10 hours on ski.

    I have zero internal engine mods beyond the titanium valve retainers, air intake, riva waterbox, riva straight exhaust setup. I also had the pleasure of meeting Dean and having him flash my ECU according to my mods and my location.

    Cylinder 1 looks like someone beat it with a sledgehammer worse than 100 redheaded stepchildren.

    There is 1 dig in that cylinder wall that I can catch on my fingernail...which on a 10 hour old motor...its enough for me. Anywho...what do I do?

    It actually blew up over a year ago and I didn't touch it...yeah shame on me. Been busy, been discouraged...been a mix of both.

    Water sat in it because frankly I am just about ready to take it to the dump and or light it on theres a bit of surface rust on internals which I am going to address in the best way possible per everyones recommendations.

    If I send it out to U.S. Chrome...I can pretty much have it repaired for about the cost of the "sleeves" that I'd have to install (parts only)

    With that being said...

    I have been told sleeves are the worst thing I can do. I was looking at Darton. I don't really care about money...I'm just hoping to make this thing bulletproof for once in its short life so my life can stop sucking as much looking at 1000lb paperweights in my back yard.

    So Darton sleeves vs having the stock ones repaired, re-nickasil'd?

    Are the Darton's harder? I eventually will get bored with mid to upper 80s and want to upgrade supercharger wheels etc. Please take that into consideration.

    Pistons/ there one brand you all recommend over another? Is there a particular compression ratio that is also recommended and why?

    I was told CP pistons etc...but I am, at this point, fully confused about my life and why I am even pissing money into this kids with ass cancer jetski

    If I am to consider any upgrades in the future (supercharger wise)...what are the benefits to adding bigger/better injectors, fuel rail, (pump?)

    Minus being able to physically turn a these require any crazy programming? I figure I'll have to bother Dean again to have the fuel curve updated etc etc...But will there be other necessary changes if I decided to add these?

    I basically crapped on a couple of valves and then crapped on my piston...I will need guides, valves and so on.

    I have seen the +1 valves etc. I understand the concept...I do not want a straight line ski that is for drag races only...I prefer the sleeper ski that craps on peoples chests as I cruise. But if I am already repairing things...and having new valve seats pressed in (I was told that's possible, don't judge)...What would you do?

    I need electronics to hold my hand because I guess I'm a moron.

    What RPM gauges, ATF ratio meters would you recommend? I have a feeling one of the main reasons for my mega failure beyond what appears to be an insanely compromised gasket in my oil pump was in fact that I was pushing too much power, too many rpms...and should have had my impeller pitched accordingly to bring things into a safe zone.

    Camshafts, who grinds them, why grind them? Mine are rusty...I have extras...speaking of Cams, let's add buckets and other crap into the mix...

    So yeah, beyond buckets and so on...I know they have values inside of them with those little counter weights/spacers...whatever those parts are. Noob in this sense...will have someone with a brain handling that part. What say you all?

    Did I mention connecting rods? Tired of typing, can I also throw any internal bearings into the mix including clutches?

    This part too. What should I be getting. I don't care if connecting rods are 4 or 500 over stock. I would rather have a legit act of god that made this ski fail in the future than a mechanical failure.

  2. #2
    Do you change your oil Frequently bwahahaha!!!!!!

  3. #3
    Sleeves can be bored, no nikasil. Mine is .020 over and been fine. Unless something changed with the SVho blocks...but I don't think so.

    Aftermarket buckets are thicker and may require Grinding the valve stem so you do not have to run a paper thin shim to get valve lash. But if you replace valves then your into it that far anyways ..

  4. #4
    MJE - Not sure who you planned on sending your block out to, or if you decided to sleeve or Nikasil, but call up . I spoke to 2 of their tech's and they both recommended boring it over the Nikasil coating. They said it's cheaper and provides a better finish.

    I'm sending my block to them Friday, just haven't decided how big of a bore I'm going with yet.

  5. #5
    If you have killed 3 motors in 10 hours you need to find out what's causing the issue or you're just going to blow up another one. Is it the same cylinder every time that is having issues? You can buy a sleeve from the GH store. Darton sleeves for that build are way overkill.

    RIVA Yamaha 1.8L Engine Pro-Series Sleeves

    Our high-quality ductile iron replacement sleeves are considerably harder and more abrasion resistant than OEM sleeves providing excellent oil...
    RY10040-SLV-615 $79.95

  6. #6

    Join Date
    Jun 2017
    Ocean City, MD
    Make sure they put the correct hone pattern on the sleeves. CP calls for a particular angle. The ductile iron sleeves are more difficult hone.

    Go big bore 1.9 and bump the compression up to 9.5. This setup is nasty and will make big power.


  7. #7
    Haven't fallen yet. MJE's Avatar
    Join Date
    May 2007
    Buzzards Bay, Massachusetts
    I haven't "killed" anything. I didn't do the work on them. I had a bit of a lemon. Technically the same requires nikasil and new pistons etc at the moment. It's been completely ripped apart 3 times now. I never was able to ride WOT until I brought it to Massachusetts. A piston literally ate shit on me 3 minutes in. There was a fresh oil change in it that had maybe an hour on it.

    The trolling I honestly found amusing. I don't proclaim to be a guru of any means and actually poked a lot of fun at myself in my post. I am not a Yamaha fact I love Yamaha...I even love this ski even though its cost me the equivalence of 3 individual skis between mods and repairs.


    I was going to drop off (3) different engines to US Chrome in CT tomorrow. Two of which I've pulled apart a dozen times and I just want a fresh coating of Nikasil on the jugs...the other I've had issues with that technically beyond my timing chain mishap, were no fault of my own.

    I had a defective head with a small pinhole leak where oil came out of that needed to be replaced...

    Perhaps the damage was caused then via no alarms going off...and the ski being ridden at idle for miles in and out of my canal system at low speed for nearly an hour each way...who knows

    There are NO internal engine modifications beyond things that strengthen it (titanium retainers, upgraded riva supercharger shaft)..

    Keep in mind...after I devastated a brand new ski with a timing chain being folded over (legit 0 hours, never been ridden)...I took it to a complete professional that knows these things inside and out who I respect and am still beyond impressed by and would use again if I weren't 1500 miles away.

    One of my pistons literally disintegrated (cylinder 1) smashed and broke the seats on the intake side of valves (bending the vales as well)

    There was water in oil everywhere when I opened the seat up. There was never water in oil before.

    I'd like to overbuild this effing thing to the point that if I decided to do a full fuel system with increased PSI from a new wheel...ground the cams...and so's ready.

    Thank you for the responses

    If anyone has experiences with US Chrome please let me know what you think.

  8. #8
    Sorry to imply that you killed them MJE. Just saying if three motors hacve eaten themselves then you need to delve a little further into whats causing the issue. If its a pinhole leak in the head great you replaced the head and resolved the issue. Rebuild it and run it. Plenty of people running 30lbs of boost on stock sleeves.

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Looking to buy a blow off valve for a gp1800 ??
    By 2017 fx svho in forum Yamaha PWC Performance (4-stroke)
    Replies: 5
    Last Post: 07-27-2018, 08:32 PM
  2. Cavitating like hell, Ski won't get out of its own way, gp1800
    By DaveMD13 in forum Yamaha PWC Performance (4-stroke)
    Replies: 43
    Last Post: 07-01-2018, 06:37 PM
  3. Impulse buy gp1800
    By MDGPR in forum Yamaha PWC Performance (4-stroke)
    Replies: 19
    Last Post: 04-27-2017, 08:27 AM
  4. About to buy a GP1800. Any problems observed with these units? Disable neutral start?
    By dolphinride in forum Yamaha PWC Performance (4-stroke)
    Replies: 0
    Last Post: 04-02-2017, 05:17 PM
  5. what the hell did i just buy
    By Bone1050 in forum Polaris Open Discussion
    Replies: 26
    Last Post: 10-27-2008, 08:46 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