2nd build.. opinions please?

[KCvale]

the Grubee Skyhawk 4GT showed up this morning.. I gotta say I'm shocked and impressed with the quality of this kit for the money they sell it for.

This kit is going into a Genesys Astra 29"er

With that big 7-speed you may want to consider a Jackshaft kit to make it a 7-speed shifter.

I really like the HS 142F with new 4G belt myself other than it is a full 1" wider than the old style due to the much better clutch housing and external offset bearing freewheel bearing mount.

Gears change everything for that little 49cc power plant.

It is pretty gutless off the line and limited to ~ 30 MPH with the stock 1 speed direct drive gears.

With just a simple 3-speed they jump off the line to ~ 25 MPH in 5 seconds and run 38 MPH with 26" wheels like this latest build.

SickBikeParts.com has a 4-stroke kit but it doesn't fully support the wider 4G well yet.

The BB shaft and crank combo is not wide enough but if you get the engine base high enough it's OK, you just have to drill new engine mount holes like this for example.

On that yellow build above I had to use the extra wide 'funky' cranks in the base kit.

Jim at SickBikes is working on a new base for this problem for their shift kit.

I have another 4-stroke shifter in the bay right now and another on deck so using my own design for now.

 

[Gutz]

very nice clean work.. I'm considering the jackshift.. this is my running errands bike.
not sure if I need it though.

 

[Tinkerbot]

I'd like to have a look at the Jawa but can't find them.. the chinese engine.. I'll see what I can do on the pic.. haven't bought it yet but it's an option.. an overkill option really.. I'm leaning more to the retro look and obviously the rotax isn't it.. I've spent the day scouring through what people are using in ultralights, R/C and kart stuff, outboards, chainsaws, old weedeaters, you name it.. I'll find the right one eventually

Have you seen some of these r/c radial engines?
Most are 4 stroke up to about 250cc.

They are a bit pricey, and I think they run on methanol, but man!
That would be one unique machine, and imagine the sound!

You may be able to find a used one for a lot cheaper than new.