Stage III gearbox vs 4G belt drive

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highlander9

New Member
Oct 15, 2010
74
0
0
Illinois
I am torn b/w the two. So far from research I've got this:

Stage III skyhawks tend to "whine," require lubrication every 2-3 wks, have to have the engager cut off so as to prevent shearing. Plus it has greater top speed because only 3.25:1 reduction. Has a metal cover which can get hot?

The 4G's 5:1 reduction makes it slower, the T-belt drive can break and needs to be replaced periodically.

Plus, what's with this whole engager business?? Is it just to engage the clutch, manually? I noticed you can get 4g w/ or w/o engager. Does that mean the one w/o "engages" automatically??

Thanks appreciate it. I am still in the process of getting a grip on the mechanics of things. So any help along the process would be awesome!
 

ocscully

New Member
Jan 6, 2008
373
1
0
Orange County, CA
I've used both the Type III gear box and currently the 4G Belt drive for the Honda motor, frame mounted with a SBP 4-stroke Shift Kit. I put over 6000 miles on the Type III before the clutch bushing wore to the point that the primary drive gear on the clutch bell managed to chew up its teeth. I ran into problems trying to get the new replacement clutch that bicycle engines sells to work in my gear box so I switched to the 4G for Honda drive unit. I've only been riding the 4G for 6 weeks but am much happier with the 4G unit. It has some problems that need to be worked thru, but it is much quieter and smoother than the Type III. While Grubee makes the 4G unit with and without the engager mech. I don't believe any vendors in the US have the model with the engager. The Engager mech. is to be used only when starting the motor and only should only be engaged at idle rpm. Rather than provide a clutch with a proper stall speed/engagement rpm Grubee came up with the Engager. In practice most people seem to try and use it as a manual clutch and try to engage and disengage it at higher rpm with disastrous results. The weak point or problem areas I've experienced with the 4G Drive are specific to the Drive that is made for the Honda Motor, and they are with the clutch , clutch bell and its bushing mount. If you are using the 4G unit that is made for the newer HS motors that come with the clutch shoes mounted to the motor?, these problems don't seem to exist?
The difference in reduction between the two drives (3.7:1 for the Type III and 5:1 for the 4G) has not been a big problem for me as it is very easy and relatively inexpensive to change the overall reduction with the SBP 4-stroke Shift Kit. But I've read where some folks feel that you can't get a small enough rear sprocket for the single speed left side drivetrain set-ups? When I switched to the 4G unit on my bike with out changing the ratios on the jackshaft my top speed dropped from 36 mph to 31 mph, but I rarely ride the bike at either of these speeds. I've just last week changed the ratios on the jackshaft and my top speed is back up to the previous 36 mph.

ocscully
 

highlander9

New Member
Oct 15, 2010
74
0
0
Illinois
Ocscully,
I got every single word you wrote! Thanks for this great insight. I now have to be patient for the HS 142F w/ the 14v 7amp generator to return to the market in a more feasible form so that I may consume it! Ok, awesome!

h9