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  1. #1

    Riva 1.8 Cam Gear Manufacturing Issue

    Hello everyone, I'm posting this to hopefully save someone from destroying their motor.

    I installed Riva's adjustable cam gears a few days ago on my conversion ski. After a few wot passes, I heard a weird noise coming from the front of the valve cover. I removed the valve cover and discovered that one of the exhaust cam gear bolts was missing, and the other was loose! To make a really long story short, 5 hours of wrenching later, the motor was out of the ski, oil pan was removed, the bolt and aluminum key were recovered, and the motor was reassembled (thankfully with no other obvious damage).

    When I was re-installing the cam gear, I found that some of the aluminum keyways were deeper than the others. This caused the bolt to tighten the key to the cam flange, leaving the sprocket loose. It actually wobbled back and forth! I sanded down the flange side of the key and now its perfect.

    Please check your Riva gears! If you line up the keys with the bolt side lip opposite the other you will be able to see if one is deeper. It's not much, maybe .010", but that's all it needs to stay loose.

    I was really lucky. I could of easily destroyed my motor.

    I plan to call Riva first thing in the morning to let them know. Maybe it was just my bad luck, but several of my keys were deeper than they should be (protruding past the gear).

    BTW, my cam flanges are not cracked (a common problem with these motors). Also, I did not use loctite on the bolts, since I was going to be trying several timing combinations.


  2. #2
    alan1967's Avatar
    Join Date
    May 2011
    unbelievable!!!let us know what Riva answer

  3. #3
    big john's Avatar
    Join Date
    Sep 2010
    Cocoa Beach, Florida, United States
    i just installed a set thursady, now i have to pull my valve cover to check !!!!!!!

  4. #4
    Site Admin Green Hulk's Avatar
    Join Date
    Apr 2005
    Morgan City, LA
    I informed Riva about your situation and they responded quickly. All cam gears in Riva's stock have been checked to ensure that inserts are correct thickness for gear. They did not find any inserts that were thicker than the gear as you described. I spoke with Pat Weekley at Riva and he will replace any inserts that are not machined correctly. If you need any help with this situation, please contact Pat directly at [email protected]. Riva's regular customer service rep (Bubba) will be back in the office next week.

  5. #5
    Thats interesting Jerry. My buddy called Riva today and spoke to Vinny, who I believe is the parts manager. He told him that they were aware of a problem with some of the older gears. My buddy asked him to please check his computer, to prove that we had purchased these gears only a few days ago. He was very thankful for the call, as my buddy was not calling to complain or ask for any reimbursement. Only to warn them of the issue that our set had. We have been dealing with Riva for many years and have never had an issue. Vinny asked us to send in pictures of the damaged bolt/insert, which I took today, and that someone was going to call us back. He was very helpful and even offered to replace the gears. Hopefully tomorrow we will know more.

    On a side note, I checked my FZS, which also has Riva cam gears, and sure enough one of the inserts was deeper than the gear. However, it was no where near as bad as the ones on the conversion ski. This set was purchased when the Riva gears first came out. So either this is a wide spread issue, or I have really bad luck.


  6. #6
    Wender Jones's Avatar
    Join Date
    Feb 2012
    Salvador, Bahia, Brasil

    Exclamation RIVA Racing Cam Gear Spockets Problems


    I also had almost the same problem with this RIVA Cam Gears last weekend

    This is what happened:

    I was using the RIVA Yamaha FX-SHO/FZ Race Cam Set (RY19040-CS628 ), with the RIVA CAM SPROCKET KIT (RY19040-ACS).
    Click image for larger version. 

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    Everything was going just fine, i already had run about 10 hours with this set, when the engine stopped suddenly. For my luck, at a *very low engine RPM...
    Later at the workshop, after have opened the valve cover, we detected the problem:
    >> The screws of the RIVA Cam Sprocket loose alone!!!!

    At the accident, it damaged intake Camshaft, *the screws, the little aluminum parts that adjust the degrees at the Cam Sprocket and also damaged the engine timing chain. All this parts are useless now.*
    The cylinder head also got a little damaged too, but for my luck, it can be fixed.

    See the pictures below:
    Click image for larger version. 

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    Im very upset because there was no errors at the mounting of the engine (it have worked very well for 10hours); and I had heard that these RIVA Cam Sprockets have given this same problem before.

    Does RIVA says nothing about this kind of problem?

    - I am thinking not to use neither the RIVA Racing Cam, neither the RIVA Racing Sprockets again.

    Then, Im figuring to replace it all with R&D parts. Like these:

    > R&D FZ/FZR/SHO RC3 Racing Cam Kit;
    > R&D Pro Tune Performance Adjustable Cam Gear Kit;
    Click image for larger version. 

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    - Do you think these R&D parts are better?
    - I imagined that because I never saw none complain about these parts, specially the R&D Cam Gear Kit.
    - I also post a thread at the RIVAFORUM telling him what happened to me. I will wait to recieve any answer from RIVA.

    Now I think that the problem is that aluminum inserts are not strong enought to support all that strenth. First they wear out and then the screws get loose...

    Well, this is my dilema by now.

    Once again I counting on your opnion.

    Best regards,

    Wender Melo.
    Last edited by Wender Jones; 10-29-2012 at 06:54 AM. Reason: few adjusts

  7. #7
    go with r&d cams and gears

  8. #8
    stick with oem cams
    riva & r&d both shit

    ask JD1 about cams

  9. #9
    The Riva cams are fine. The problem is the aluminum inserts for the sprockets. I will take a good and bad one with me to the hydros for anyone who wishes to see what I am talking about. You need to grind/sand down the cam flange side of the aluminum insert until it is flush with the cam sprocket. Good luck getting it back together buddy....


  10. #10
    big john's Avatar
    Join Date
    Sep 2010
    Cocoa Beach, Florida, United States
    i just pulled my valve cover and checked mine, their tight, no movement on the gear at all, but i'm interested in seeing your bad parts, it least i know i should check my riva gears every 10hrs or so

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