Can a Robin overheat?

Discussion in '4-Stroke Engines' started by mifletz, Nov 4, 2009.

  1. mifletz

    mifletz Member

    If a normally functioning Robin 35 is used for an hour going up a very steep 10 mile hill at 6mph on a pedal-assisted friction mountain bike with 7/8" roller at maximum gas, is there a risk of it overheating and seizing up?

    Will the engine give premonitory distress signs?

    And on a flat surface, for how long can the engine take maximum speed non-stop (in my case c20mph)?

    Indefinitely? Or is it best to stop and cool off at intervals?

    How heat-tolerant are these engines of heavy and very heavy use?
    Last edited: Nov 4, 2009

  2. retgi

    retgi Member

    I'm by no means an expert on these engines nor any others but it's never good to maintain WOT (wide open throttle) on any engine without backing off now and then. Just my .02 cents.
  3. fetor56

    fetor56 Guest

    An engine is like a woman....treat it real good & give it WOT only occasionally & it'll love u forever. :grin5:
  4. Bill555

    Bill555 Member

    If you can maintain 6 mph, then I think your hill isn't that steep and you should be all good. I would only worry if you were going really slow and doing this everyday. Then, I would worry that would wear the clutch prematurely.

    I wouldn't worry about about wrecking your friction drive. Ride WOT if you want. I used to have 1.1hp 7/8 inch friction drive on a tandem. I always thought I would burn out the clutch but never did. I've tried to go up many hills with 2 people on it in which I've had to turn around for lack of torque.

    One more thing, the throttle doesn't directly affect how much fuel you are burning. The throttle simply controls how much air can get in the engine. So when you open the throttle you are just allowing the engine to rev up (if it can). So when you are going slow up a hill, you are not working it as hard as you might think.
  5. seanhan

    seanhan Member

    If You Want Fulltime Wot

    Get A Tanaka !!!!
  6. give me vtec

    give me vtec Active Member

    I have ridden mine for more than 3 hours at a time in the HOT 110+ degree dry heat. I will say that this is by far the most forgiving engine I have ever seen. I ran it for the first 20 minutes with no oil the first couple of times because I was an idiot and forgot to put oil in it. This thing just keeps on going. I have ran it HARD, and I mean very HARD for six months now.

    Three things...

    change the oil very frequently with a good oil (I use Valvoline in mine and 10w-30 mobil1 in my dads). Change it every week or two depending how often you ride. I mean come on... its 100 ml of oil and easy to change. Dont be lazy.

    Keep the air filter clean... I use the k&n filter cleaner on the foam and dawn soap on the white felt. Although I think I am just going to replace that white filter next time, might be better in the long run.

    Dont ride full throttle for more than about 15 or 20 seconds.... ever. If you are going down hill... dont use much throttle, and never wide open throttle.

    all that stuff should make your engine last a while... long enough to save $155 that you can send to silvaire for a new one. Just got mine today and it looks great.
    Last edited: Nov 5, 2009
  7. cycledude

    cycledude Member

    It depends on how much load is on them, in your case I would caution.
    I know the landscape people turn off their tractors for a bit every once in a while and let them cool off.
    For a more precise answer I would ask the lawnmower repair people what they think, I know that is the last place the landscape people like to go to, $ repair.
  8. I've had 3 Robin EHO35s on 3 different MBs now so I feel I have a fair amount of experiance. I occationally ride wide open for as much as 1/2 hour at a time with no ill effects so far. These are really excellent,tough, well designed, well built engines and are fan cooled, so there shouldn't be a problem running them hard. I do assist them by peddaling when starting from a dead stop and when climbing steepish hills, both to help preserve the clutch and to prevent lugging them at lower speeds. As vtec said, change the oil often (no oil filter), use a high quality oil (I use Castrol Syntec 10W40), and keep the air filter clean and your Robin should give you years of great service. You may have to adjust the valve clearance every few years, or have a competent small engine mechanic familiar with Robins do it for you if you aren't comfortable doing it yourself.
    Last edited: Nov 5, 2009
  9. give me vtec

    give me vtec Active Member

    wow.... 1/2 hour at a time??? I may just rethink my driving habits a little more to the faster side.
  10. Happy Valley

    Happy Valley Active Member

    Well one thing, you'd only get 6 miles up that 10 mile hill in an hour. :devilish:

    It's good to remember that these are 8 lb. weedwacker engines and the scenario described above (10 miles up a very steep hill) would IMO qualify as extreme use. I'd be inclined to say if asked to perform that kind of duty on a regular basis the engine's usable lifespan would be seriously shortened versus being used on predominately level terrain.
  11. robin bird

    robin bird Member

    I just ordered a kit with the Robin chaindrive , from staton. I wanted to have 1 quite rider,high mileage and little vibration--plan on a real long trip next June.
  12. Old Bob

    Old Bob Member

    Getting back to the topic of the thread...:thinking:

    Most of the mini four strokes give warning they are running too hot. Mostly you'll notice a loss of power, burning oil when they don't normally burn oil, sometimes pinging.
    Most people will instinctively back off and let the engine cool,its fairly intuitive, if you can't recognize the signs you probably can't balance a bike...
  13. Thanks Bob, good advice. Mine have been close a few times, especially the friction drive bike. I think some of us have a good feel of our MBs, some others do not, but are learning from guys like you. I have developed the feel of how an engine is doing. Now I need a tach. The new GEBE drive bike has hit 35mph down a hill, the Robin was screaming a happy song, but no stock 4 stroke engine will tolerate that sort of extreme rpm for long.
  14. Old Bob

    Old Bob Member

    Honda has no issue with rpm, I'm sure the Robin wouldn't either, buts is a good to stay within manufacturers recommendations.
    The Honda will self limit rpm with its small carb and ports, no load it won't rev over 7800 rpm or so. I forgot what I tested a EHO 35 to, about the same from what I recall.

    Sendec makes a good tach.