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Mar 26, 2020
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Norman Oklahoma
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I'm kicking off another quick build, I have a mongoose dolomite, a big wheel bike.

It's amazingly easy to ride, I just don't like some of the cheap components, but those will be changed.

With a 100cc 2 stroke coming any day now, I'm ready to make it a really fun bike.


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To be honest, with a lot of examples that I've seen, the mongoose dolomite is not designed to have a engine kit installed on it. First of there is very little room for everything.

So to make things fit, the bikes frame in this case needs to be modified. Starting with the back bone, I'll have to cut and weld it.


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that's more than i thought you'd have. you could probably get a plug wire to fit, even if not what came with the kit.

relocate brake cable if needed.
Another hurtle is the chain alignment is for narrower tires, so to fix that is get a jack shaft kit or make one, with too many projects going on, I will probably buy the kit from eBay.


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A typical jack shaft kit for this type of engine. It would be easier relocating the back bone, this will give the carburetor and spark plug to fit. One other issue is the front down tube is to big around to mount to.

There will be fabrication needed. Which is all right with me, I also want to convert the front forks to have a suspension using the stock forks, by adding a Springer type of suspension but with two shocks attached to rockers, if that makes sense. Like this rat rod motorcycle front suspension.


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The more I try to make this basic kit to fit, the more problems I run into, added problems such as the sprocket center hole is smaller than the hub. In my opinion the gas engine kit for a dolomite will require a lot of modifications to make it work, your best bet will be to convert to electric.

But in this case I want a rugged military look and I feel the gas engine will accomplish that.

Next step is to cut the backbone.


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Good news, no need to cut the back bone. The engine will fit, but the carb will need to be mounted differently. I'll use the harley Davidson method lol. 90 degree intake manifold will fix that problem.
As I said before, this bike wasn't meant for a gas engine kit. Back to the rear sprocket, my disc brake caliber and the sprock wants to share the same space, more problems lol


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i've seen a lot of disc gas builds and usually the disc is behind the sprocket (using a much larger disc for the brake). there are some sprockets that are made with an offset to mount both the gear and the disc on the disc mounting flange on the hub. then you use an extended caliper bracket to move the caliper to match the new larger disc. (it can be tricky though)

you could offset mount the motor like they do for the OCC bikes instead of the shift kit. would probably have to come up with your own mount or modify one of the OCC ones as they have a flat tube between BB & rear stays. (not typical triangle like most bikes)
the CNC offset mounts will probably be too tall for your application and i don't know if the offset would be enough anyway.
Thanks for the heads up, I'm still gonna use the jack shaft, more expensive but easier to deal with.

The little engine will fit in a dolomite, shortening the motor mount made a big difference. The carburetor with a simple 90 degree elbow will fit too.

Today I was able to bend the new exhaust pipe, tomorrow I'll be welding it together.


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