GEBE engine question

Discussion in 'Rack Mounted Engines' started by JemmaUK, Oct 26, 2007.

Tags: Add Tags
  1. JemmaUK

    JemmaUK Guest


    A thought has been sitting in my head recently and after visiting the hospital for 2 hours with my 4 year old having to have 4 teeth out under general anaesthetic... I needed something to calm me a little so I tinkered for a while.

    I learned how to take the engine off the mount etc - its simple, but a pain to get back on sometimes but i also decided to take the shroud off the engine which makes it look a million times better.

    The question is - is the motor shround there for any reason? I understand its there to protect against the heat but I dont see any way it acts to direct the airstream for the cylinder..

    Could I do any damage to the motor with the shroud removed?

    Jemma xx

  2. DougC

    DougC Guest

    The -multiple- engines that GEBE uses are small utility types so it can't be said definitely for all of them, but it's probably just there to keep humans from touching the hot parts.

    I have the Robin-Subaru engine and its cover is bright yellow, and I planned on navy blue for my paint job. I may remove the cover as well, rather than bothering with painting it. If anything the airflow would seem to improve, especially over the top of the cylinder head, which is "closed off"....
  3. JemmaUK

    JemmaUK Guest

    Looking at it that is what I thought too - as on mine the top of the head is completely covered apart from some small apertures.. It looks alot more in keeping without that plastic monstrosity.

    Its odd how mucking about with motored bikes can be therapeutic - its amazing how persistant an image a bleeding 4 year old can be :(. An hour of MB'ing got rid of it until about 2am this morning when it came back with a vengence :cry:

    I am going to run the bike sans-shroud for a while and see what happens but I think it should be ok. Looking at the engine itself I am surprised that something that looks so diminutive has got so much go :)

    Jemma xx
  4. srdavo

    srdavo Active Member

    small engine flywheels are also blowers. Much like the way a vacuum cleaner moves air. The plastic covers allow this blown air to travel across the engine for maximum cooling. Way more air than what you could create just by traveling down the road.
    IMO....keep your covers intact. Paint them if they are ugly...but keep them on.

    there's a nickel's worth of my 2 cents! (keep the change :lol:)
  5. Jim H

    Jim H Guest

    Personally, I think it may just be a cosmetic thing as well as a miniature fender type of a thingy;:shock: It does streamline the looks of the engine on that side...without it, it doesn't look bad either. :???:It could also be there to keep us from jamming our fingers into it accidentally!?;) srdavo is probably on the money though; keep the cover on if you can.:grin:
  6. JemmaUK

    JemmaUK Guest


    well I just went for a short run - short because it was tipping it down and tipping it up as well.. I *really* need mudguards.

    The engine seemed to bog a bit, but when its tipping it down onto a cold engine that didnt surprise me and it seemed fine when it warmed up. It might have also had something to do with the fact that the earth wire to the mount had come loose *sigh*

    regarding the removal of the panel cover it doesnt seem to make a massive amount of difference because the temperature of the air across the cylinder seems the same as it was when the panel was on, the temperature at the end of the exhaust doesnt feel hotter either. It vastly improves the look of the engine.. although that is my personal opinion.

    I have made a couple of other changes -the main one being relocating the indicator/tail/brake light right to the back of the bike - mounted (using a longer bolt) to the top mounting of the clutch/driveshaft cover. It seems to work well and will be much more visible.

    Jemma xx
  7. sabrewalt

    sabrewalt Guest

    We want Pictures!!

    Pictures??? :shock:
  8. JemmaUK

    JemmaUK Guest

    Pics as requested...

    Attached Files:

  9. DougC

    DougC Guest

    I'd like to change my earlier response to "it depends on the engine and mount".

    I got the second muffler attached to my Robin-Subaru 35cc and while I was doing that, I was test-running it a bit with the cover off (a small part of the engine cover and muffler heat shield around the exhaust had to be cut away).

    ...I didn't actually try riding the bike, but I could tell that even running the engine stationary, the R/S does pump a LOT of air around the cylinder cooling fins. And the way mine is mounted, the muffler is on the front side of the cylinder, blocking airflow to it. I expect I'll be keeping mine on.
  10. loquin

    loquin Active Member

    by forcing a constant flow of air past and the fins, the engine temp can be held more stable, and by stabilizing the engine temp, it's easier to minimize emissions.

    Open engines will have zero air flow at a standstill, and therefore run hotter than when they're in motion.
  11. keep the shroud on

    the plastic shroud is there for a reason just like fins are on the fly wheel for a reason. Cylinder cooling. The engine may run fine for now but [IMO] the life of the engine will be cut short. Do your bikes engine a favor and put the shroud back on:smile:
  12. gone_fishin

    gone_fishin Guest

    smaller engines are smaller for many reasons

    yup...forced-air cooling is factored in along with all the other
    values used during design, such as fin size, shape, & placement...

    that is all :)
  13. Yep...she might definitely heat up if ya set and idle for awhile...that little squirrel cage in there is there for a reason, although the engine does look quite nifty without the shroud in my opinion as well.
  14. Eco Speeder

    Eco Speeder Member

    That looks quite wicked! How fast?


    p.s the housing is for safety really. The afore theories are true if one is running the motor but not moving.
    Last edited: Jun 1, 2008