Thanks Thanks:  0
Page 1 of 2 12 LastLast
Results 1 to 10 of 17

Thread: Boyesen reeds occured drop in rpm's

  1. #1
    Team Member
    Join Date
    Mar 2013
    Posts
    8
    Post Thanks / Like

    Default Boyesen reeds occured drop in rpm's

    Mounted Boyesen two stage power reeds on my Mercury 55 Sea Pro on a Gemini Zapcat. I tested performance before going from stock reeds to Power reeds. I got 61,1 mph at 6100 rpm's. This is a often seen performance with this setup. Motor is stock only rpm limiter cut. I was spinning a Merc. 12X18 TH cleaver.

    The test results with Power reeds were disappointing. I achieved 57,5 mph at 5700 rpm's.

    Further more I had a idle rpm raise to 1100 rpm's. And I had a motor stop when going from full throttle to idle. The engine would start immediately Again.

    I'm about to go back to stock valves again but would give it a try for a good advice here.

    Regards Brian

  2. #2
    Banned
    Join Date
    Nov 2016
    Posts
    289
    Post Thanks / Like

    Default

    sounds like something wrong here.
    first off the gear ratio is 1.64 to1 so 18 pitch at 6100 so yeah that is possible with a nice slip percentage of around 3.5%. great speed.

    57mph at 5700rpm is giving same slip type figures, so you just got a bit of rpm limiting going on.

    the reeds from boyesen have been known to do this to bikes years ago. it could be a bad set and your just the unlucky one.

    This is why smaller firms like CCMS get real food reviews as they are not into 2 mile long mass production lines just pumping it out and not talking to the customer 1 on 1.
    More chance of getting a set of "not exactly good" reeds from this type of company.


    So what exactly did you change ?
    did you change just the reeds and put everything else back as per normal ? what about reed stops etc.
    did you leave anything out or add anything else ?
    have you checked for any air leaks on the housing/gasket surfaces.
    to lose 400 rpm top end is a big deal, have you had a good look at them to see if they are the correct ones for your motor that is not a tuned race prep motor ?
    the reeds you have might be for a hydrotec type of tune up ?

    what did they look like compared to the stock reeds ? any shape change ? or just the material ?

    I know some of this might seem a bit simple, but often its the simple things we miss out on .

    .

  3. #3
    Team Member
    Join Date
    Mar 2013
    Posts
    8
    Post Thanks / Like

  4. #4
    Team Member
    Join Date
    Mar 2013
    Posts
    8
    Post Thanks / Like

    Default

    Attachment 62857

    This is how it looks. I have used new gaskets and bolts are torqued properly and as specified in a circle from inside to outside on the manifold.

    I have don nothing else. And I don't know how to check for leaks.

  5. #5
    Banned
    Join Date
    Nov 2016
    Posts
    289
    Post Thanks / Like

    Default

    there is no pictures coming up !!!

  6. #6
    Team Member
    Join Date
    Mar 2013
    Posts
    8
    Post Thanks / Like

    Default

    Sorry about the pictures. I doesn't work

  7. #7
    Team Member
    Join Date
    Mar 2013
    Posts
    8
    Post Thanks / Like

    Default

    can be seen here: https://youtu.be/FX4J3YYHgog

  8. #8
    Team Member hydrospeed77's Avatar
    Join Date
    Jun 2016
    Location
    Ontario, Canada
    Posts
    40
    Post Thanks / Like

    Default

    What model yer is your motor?

    I have a 1996 60 (850cc, 1.64:1 gears) and installed Chris Carson Reeds this past winter. I notice no change at all in performance in any way. No more power up top; no better idle. The engine behaves the same as far as I can tell. Although my application is not very high performance. I see 5100rpm max regularly and maybe 5400-5500 when I really lighten the load and trim up for a top speed trial.

  9. #9
    Team Member
    Join Date
    Mar 2013
    Posts
    8
    Post Thanks / Like

    Default

    Its a 2004 model 967 cc 1.64:1 gear.

  10. #10
    Banned
    Join Date
    Nov 2016
    Posts
    289
    Post Thanks / Like

    Default

    How did you remove the limiter ? if it was a wire simply disconnected , could you have accidently put it back on ?
    I am thinking of simple reasons why you lost the extra rpm .
    Was the reeds a nice fit when you put them in ? daylight test etc.
    I am not in any way saying your daft, doing it wrong or anything like that, I am looking for a reason that can be easy rectified.
    I have often been in a rush and made a complete *** of myself . ha ha
    Likes Galeon liked this post

Thread Information

Users Browsing this Thread

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

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •