How does the GEBE clutch work?

Discussion in '4-Stroke Engines' started by KevinK, Nov 26, 2010.

  1. KevinK

    KevinK Member

    I have exactly 1622 miles on my GEBE Robin kit and have followed all the maintenance according to the Robin owners manual and of course GEBE's advice.
    Is the clutch part of the Robin engine or is it GEBE's? I look at that little engine that gets me to work and back 67 miles per day and I simply do not understand how this thing works. I rode in the rain last night for over an hour and that belt did not slip a bit and it was a total deluge with fog and the whole works!
    My original drive gear and belt have little wear at all! But I always pedal to get the bike going and I always pedal up any hill. Its a great work out!
    On tonight's commute home from work it was 12 degrees. And the head winds were 40 mph gusts with brutal wind chills! Quite a change in weather from yesterdays rain and mid 30's temps!
    That clutch seems complex to me. Is there any maintenance to be performed on it or does one just ride and forget about it? The system seems sealed well from the elements. Knowledge is the answer to potential problems out on the road.
    That Robin/Subaru engine seems to be bullet proof. I change the oil every two weeks or about 600 miles or so. Oil is cheap! when I check the oil its never low.
    I am not ever going to mess with this engine. I have a relative that is a great engine mechanic. I showed him this bike and kit and I am sure he can handle any engine maintenance that will come up. Robin/Subaru has plenty of tech manuals on their web site for mechanics to look at!
    My plans for this commuter bike are for a whole lot of miles to be put on it!


  2. Happy Valley

    Happy Valley Active Member

    The clutch is a standard 76mm two shoe, one spring affair that is part of the engine and like tens of small gas engines of the utility type with centrifugal clutch and a similar displacement use. The clutch drum is said to be 78mm and is part of whatever equipment you attach the engine to.

    engines 008.JPG

    I have over 500 hours on some engines and clutch shoe replacement has been a non-factor. Should you need to replace them, they are cheap and held in by just two bolts.

    This is gonna of course depend on use. An old mechanic that used to work for my dad said when I asked him once how long the new brakes he was installing in one of our trucks would last:
    "Depends how the person drives, some people ride the brake and get 10K miles, others who know how to drive get 40K"

    Running time is the key measurement on serviceability with these engines, the number of miles being arbitrary and subjective according to user and equipment. I use the small, inexpensive electronic tachs on my bikes that keep a running time tally in hours and schedule whatever maintenance accordingly.

    Robin rates these engines for 500 hours continuous duty, industrial use.
    A good friend runs a large contracting outfit, they use the eho35s on power concrete screeds and that matches their equipment service program, they replace the engines rather than repair them, it being more cost effective and the engines are relatively inexpensive.

    I think engine life will depend greatly on a number of factors.
    The engines my contractor friend uses are subject to a very dirty and dusty work environment and are used hard by employees. Some people take better care of things than others. We all probably know someone or have ourselves a gas weedwacker that has been running for years.

    I believe a utility engine on something like a weedwacker doesn't place a big load on the equipment, cutting grass and at high rpms, and most folks run theirs maybe an hour or less a week and often not year round. Using that engine on a chainsaw would be a different scenario. Count the hours.

    Placing a 35cc engine on a 40 -50 lb bike with a 200 lb rider, add gear......and it can be somewhat a different story.Take that engine apart and you see a piston with the profile of a large coin.

    Of course, gearing and pedal assist plus the inherent overall and remarkable rolling efficiency of a bicycle are without a doubt mitigating factors. Pedal to start and not yanking on the engine with a big load to get rolling from a standstill, warming the engine in cold weather a bit, etc

    I'm a real bugger for maintaining things, paying attention to the air and fuel filters, frequent oil changes with good quality oil, checking valve adjustment at 100 hours, fresh fuel and proper storage if you lay the engine away for the season I think go a long way in getting good life out of them. Plus I don't try to kill the thing, they have limits and I remember that coin sized piston. :grin5:

    There are a couple three other maintenance quirks with the eho35s I found over the years, perhaps somewhat idiosyncrasies on my part. I lack the time right now and don't want to bore anyone but if interested I'd be happy to discuss that in a latter post.
    Last edited: Nov 26, 2010
  3. augidog

    augidog New Member

    happy valley, that was really very good. kevin, now that you know that stuff...the "GEBE" part of the clutch is the black cylinder bolted to your engine. it's very simple, inside is the drum happy valley mentioned, attached to a shaft supported by a bearing. the other end of the shaft is where you attach the drive-gear. i can't do any linking on this mobile, but i bumped a thread in the "vendor area" about the golden eagle clutch assembly, where you'll see a couple nice close-ups of the part.
    Last edited: Nov 26, 2010
  4. ibdennyak

    ibdennyak Guest

    There are a couple three other maintenance quirks with the eho35s I found over the years, perhaps somewhat idiosyncrasies on my part. I lack the time right now and don't want to bore anyone but if interested I'd be happy to discuss that in a latter post.[/QUOTE]

    Please do. Can't have too much information.
  5. KevinK

    KevinK Member

    How the darn thing works and why I ride it!

    Thanks guys for the posts!
    I will go over there Augi to check out your posts.
    BTW, Juls and Dennis have looked over my new engine mount. My use of the GEBE kit might be on the extreme end of things but in the long run what I break or what works is good for all in this community! I have looked at what I want to do this year with cycling in general and I plan on using commuting as a training aid and not using free time for cycling. The motored bike will be a very important part of that mix. I am getting an idea of my personal limits on cold weather cycling right now! Another interesting aspect of motored biking as an ultra cycling athlete is the work out value of riding that motored bike. In the beginning of my motored biking I believed that there was to be zero work out or training value. That opinion has changed over 16oo miles of commuting on this kit. I did have some issues with my original mount. You caught my mistake Augi! Thanks! Anyway, I have some pics on my new blog about motored bikes.
    Anyway, I am kind of in a gray area of "real" cyclists with this motored bike. But let me tell ya the training value is real. I could go into this in great detail but its not the preview of this site.

    Dennis says that I am good to go with this new mount.

  6. Virginian

    Virginian Member


    Like you, I also do a lot of riding on a regular pedal bike and I pedal my motorized bike just like it was a regular bike. Sometimes I don't pedal it very hard but sometimes I pedal for all I am worth like when going up hills or trying to keep up with traffic.

    I agree that there is a real training effect. However, it takes a lot of miles. On my motorized bike I cover at least twice the distance in the same time compared to my pedal bike and it is less effort. When I am pedaling my pedal bike really hard on a hilly route, 30 miles will leave me pretty tired. On my motorized bike, I can ride 80 to 90 miles and not feel tired. The difference opens up all sorts of new route possibilities.