Reliability of 4 cycle clutch and gearboxes



Can anyone report on the reliability of clutches and gearboxes for 4 stroke 50cc motors?

The gearboxes that I know of (by name) are the Grubee Skyhawk II type, Dax type and the JL Hoot type. Which ones will last over the long haul?

I know a few years ago there were some bad gearboxes being offered but this may have been cleared up.

Are there other gearboxes for the 4 strokers?

Can anyone confirm long term reliability of the clutches and gearboxes?


Skyhawk II:

JL Hoot:

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I have probably around 4,000 miles on the grubee gearbox and the only thing replaced has been the clutch spring and clutch bushing at about 2,000 +

Large Filipino

The Titan is solid. Remove 4 bolts and you can put that gearbox in your pocket. 500 miles with some hills and some pedaling with the steep stuff but never had to get off the bike like I have to do with MOOP (my Happy Time) so I've given it some slip.
And when I checked my clutch pack yesterday I see very little wear if any at all. I may take some pics today.


For the moment the Grubee is the tried & proven contender but i've not heard any bad reports about the Dax either.Let's see how the new Dax in-frame gearbox goes.


I the Skyhawk II- no problems, but many less miles than those above.

To tell the truth, I've not heard anything good about the Hoot. I'm not saying that there are not people who are happy with it, but I have not heard from them.

Minnesota Hyena

i have grubee kit and the noise from the gearbox is excruciating.
once my clutch spring broke apart(i think it's from overheat of gearbox)
i'm thinking of making my gearbox "oil bath" type as some people seems to have done it already. but i worry if oil is going to leak.


Mine is pretty quiet and I use grease, but by using grease, I don't mean some on the gears, I mean a whole lot of a very good, industrial quality grease.

That being said, in an early thread about the Dax 4 stroke, Augi mentioned trouble with the clutch springs. I think he found that the problem was more that the clutch arms were not rotating freely on the pivots, causing binding. The solution was to disassemble the clutch and lightly lubricate the pivots. There are significant differences between the Dax kit and Grubee, but the clutch looks very similar. I think it's worth checking out.