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  1. #1
    Rocky_Road's Avatar
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    R&D grate...first run!

    Just got back from trying out my new R&D intake grate on my MSX 150.

    Very pleased with the performance. Definitely a grate that loves the chop! Tropical storm Fay gave me some decent waves to test on...and I noticed an increase in RPM's (around 100). Wasn't expecting this...and am wondering why?

    Also noticed that the minor porpoising that I was having around 35 mph, in anything but glass, is gone. Once again...not expected, but very welcomed!

    Only thing that I am concerned with, is a very slight hint of cavatation when I 'floor' it. It only lasts an instant...then all is fine. I am wondering if the OEM bolt that I used, is the problem...since the R&D is chamfered for a oval head screw, and the bolt is not flush with the grate.

    Just to note: the OEM grate was NOT siliconed around the bolt, only at the rear lip. I did the same with the R&D...even though the service manual says to seal both ends. I see no reason to 'glue' the front to the hull....
    Last edited by K447; 06-26-2014 at 09:16 PM.


  2. #2
    Moderator beerdart's Avatar
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    With the R&D you are top-loading the pump. So you will have some cavitation out of the hole but better hook-up in some chop. No reason to seal the front but you better seal the shoe and anything where suction is present.
    Last edited by K447; 06-26-2014 at 09:15 PM.

  3. #3
    I'm feeling naturally aspirated today pirate33's Avatar
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    For all around riding the R & D is the way to go-my front bolt is flush with the grate....I guess Al corrected that?, can't wait to try out different combo's or wedges with the JD when I get it back from Randy

    Beer don't you need a little sealant on the front to keep water from entering the bolt hole?

  4. #4
    Rocky_Road's Avatar
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    Quote Originally Posted by pirate33 View Post
    For all around riding the R & D is the way to go-my front bolt is flush with the grate....I guess Al corrected that?, can't wait to try out different combo's or wedges with the JD when I get it back from Randy

    Beer don't you need a little sealant on the front to keep water from entering the bolt hole?
    Hi, pirate!

    Next time you are under the hull, could you snap a picture of your bolt setup? I assume that a machine shop could change the chamfering to a recessed area...but I'm sure that this would void any warranty. I would prefer using a bolt, over a machine screw...if only for the ease of removing, and less likelyness of 'buggering' up the head.

    I used Marine Goop on the bolt threads...no chance of water entry, or vibrating loose.

    One other thing that I noticed on my first ride...back end seemed a little skittish, at high speed. Wasn't expecting this, and am wondering why? Don't get me wrong...I like the feel! Sort of like the NASCAR driver radioing in that "I'm loose in turns 1 and 3..." Dale Sr. (#3) used to say "loose equals fast...leave it alone!"

  5. #5
    ph2ocraft's Avatar
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    Quote Originally Posted by pirate33 View Post
    For all around riding the R & D is the way to go-my front bolt is flush with the grate....I guess Al corrected that??
    Nothing a good hardware supply house doesn't have.

    Quote Originally Posted by Rocky_Road View Post
    Hi, pirate!

    Next time you are under the hull, could you snap a picture of your bolt setup? I assume that a machine shop could change the chamfering to a recessed area...but I'm sure that this would void any warranty. I would prefer using a bolt, over a machine screw...if only for the ease of removing, and less likelyness of 'buggering' up the head.
    Simply use an ALLEN headed tapered stainless screw. It better mounts the intake grate, less chance of coming loose and doesn't bother the water flow into the tunnel.
    .
    Last edited by K447; 06-26-2014 at 09:15 PM.

  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by Rocky_Road View Post
    ...a picture of your bolt setup?
    He already did - see photo (grate not sealed, mounted just for the photo).

    I assume that a machine shop could change the chamfering to a recessed area...but I'm sure that this would void any warranty.
    I would prefer using a bolt, over a machine screw...if only for the ease of removing, and less likeliness of 'buggering' up the head.
    Use a hardened bolt, buy several and replace it as it gets worn. Looks like a nice hex drive bolt in the photo.

    I used Marine Goop on the bolt threads...no chance of water entry, or vibrating loose.
    Why wouldn't you use Locktite?
    ...
    The stock MSX grate and hex bolt create quite a void area around the head. I would imagine this can create turbulence and possibly some cavitation in the water stream.

    Machining the R&D grate to accomodate the large flat stock MSX bolt head will weaken the grate (maybe not too much, but why take the chance?). There are a lot of different forces applied to the grate at speed...

    A smooth flush bolt should work well.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	R&D 650 intake grate in Al's (sold to Pirate3) Matrix 02.jpg 
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  7. #7
    desperado's Avatar
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    Great to hear.... I also was happy with the results.....

    I just got a used R&D780 grate to try... I'll compare notes with the R&D650.... just for the fun of it.

  8. #8
    Rocky_Road's Avatar
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    Quote Originally Posted by ph2ocraft View Post
    Nothing a good hardware supply house doesn't have.



    .
    My google search didn't really get me anywhere...just one that matched your suggestion, but I would have to buy a 'trainload' of them!

    Anyone know where to get a handful (8mm x 1.25")?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  9. #9
    rob2337's Avatar
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    You can get them from Mcmaster Carr. 18-8 Stainless socket head cap screws.



    http://www.mcmaster.com/

    Part# 92125A292 (for example)

  10. #10
    Moderator beerdart's Avatar
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    http://www.mcmaster.com/ Page 3021 Oval Head SS Metric

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