Mongoose beast

Those are really cool looking and would make a nice platform for a build, the only issue I see with them tho is the small frame will make installation a bit tricky... not impossible, but tricky like needing some minor cutting and fab work. I did my mountainbike with a 66cc engine and it has a small frame, but not quite that small and there's very little room for the engine so I had to do some fab work to get my engine to sit in the frame the way I wanted it to, it was a tight fit but I got it in there and working, but these frames look even smaller... Here's mine for comparison and you can see there's almost no room behind the carb and I had to get a special intake duct just so I could use an air filter... but it was worth it in the end.

Here you can see it's a tight fit, what you can't see well is the mount tabs on the lower tube that the engine bolts to... Also notice the lack of clearance for an air filter... I fixed that problem since this pic was taken, but this will give a basic idea of how tight the clearances are in a small frame bike.. I really like those fat tire bikes tho and may consider one for my next build anyway...

I know it has been done before. I think maybe the 7 speed dual disc could possibly run a shift kit, but not sure if there is enough room between the seat post and the rear tire for the jack shaft....

Sure would be fun to cut it up and put a curved drop loop ,drop a 212cc in and it would be a good ride..............Curt

I've been hollering for someone to motorize a Beast or Dolomite since they appeared. But so far the only one I have seen had frame mods to the seatpost and toptube to stuff the ht in. Lots of offset to clear tire and I thought it could have been done better.
Looked cool, but a bit of a hack.
Still waiting for someone here to document building one.

Hey maniac - here's a Dolomite that I did with a SBP HD shift kit. The engine barely fit. I had to tap wider holes in the front mount to make it work because it wouldn't fit with a plate/u-bolt adapter. Other than having to buy a longer 5/8" shaft and fabricate a longer arm for the chain-stop, it pretty much all worked out fine.

It's the bicycle equivalent to riding around in a tank. I love climbing hills & riding wheelies around in the dirt in low gear. It takes a while to get up to speed, but it's actually pretty fast.

Oh, forgot to mention that I did have to buy a lower profile rear tire. The stock one rubbed the jackshaft-to-engine chain & it would have eventually been a problem. It's another "barely fits" item on this bike, but it works just fine.

The disc brakes are actually pretty good. They squealed a lot in the beginning, but they are starting to be a little quieter with some use.

I really like how you built your Dolomite bike up Bzura, I bet it rides so smooth. Makes me want one

Bzura said:

Hey maniac - here's a Dolomite that I did with a SBP HD shift kit. The engine barely fit. I had to tap wider holes in the front mount to make it work because it wouldn't fit with a plate/u-bolt adapter. Other than having to buy a longer 5/8" shaft and fabricate a longer arm for the chain-stop, it pretty much all worked out fine.

It's the bicycle equivalent to riding around in a tank. I love climbing hills & riding wheelies around in the dirt in low gear. It takes a while to get up to speed, but it's actually pretty fast.

View attachment 71171

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Nicely done! I would have never thought a jackshaft would fit without mods!

The problem with us using the go cart clutches and four strokes on our bikes is that the engine needs to be offset to a big degree and then you have a engine sitting 1 foot to the right of your bike. With the fat tire, the engine may be able to sit in the middle. This interests me.

Hey bzura. My first post here, awesome site, great people.

Got a question. Would you build another motorized dolomite to sell just the way pictured? If so, how much would you charge for it? Total price including the Jack shaft...
And possible shipping to miami? What would it cost? If your not interested maybe a ball park figure would sure help. I'm sure you knew somebody would be interested in this lol. Awesome build I must say

A question, would it be worth the extra $50 for the disk brake setup? What gage spokes do the wheels have? You guys have my brain going (Bad but good? ) LOL............Curt

Hello Bruza, hey I like your Mongoose Cruiser. Can you post more pics of the front sprocket assembly. I'd like to see how the chain is connected from the motor down to the pedal sprocket.

Thx, Wicker Bill

Curtisfox: it's worth more than $50 to have front & rear discs & the 7 speed shifter. Coaster brakes only on a motorized Beast is just plain stoopid. May as well take the coaster off & just drag your feet. Besides, the Beast's frame is a tighter fit for an engine. I don't seven know if you can squeeze one in there without cutting, welding or offsetting like crazy. The Dolomite is tight, but it can fit with simple mods.

wicker:Bill: I'm out of town right now so I can't post any pics. It's a shift kit from Sick Bike Parts that connects the engine to the pedal's chain. The setup is commonly referred to as a jackshaft.

My thinking is to get the Dolomite. just for the wheels ( hate the red though ) Make my own frame ( board tracker style ) use a small 4 stroke for a awesome soft rid every day bike. I think one could take off the rear sprocket and put a free wheel in place ?

Hey I built one the best way is to extend your drive sprocket 3inch use two cluch covers hollow out the first and use the other the same as always then extend the cluch operation tube and put the two together with your new cluch tube going through the middle. For your rear sprocket just put three standard motorized sprocket donuts instead of one when putting on the sprocket and walaa u have a regular mounted motor on a beast that works. You need to weld the new drive sprocket to a hardend pipe 1inch round 3inch long and hollow weld I'd directly to the drive sprocket still attached to the motor. We'll that may not be everything. Also your going to have to. Extend the rear tire axel two inches. So u can widen the space were the tire is. The chain will rub the frame if u don't. Cut the carb intake to we're your carb almost hits the motor. Then get rid of the old red carb filter housing. And use just the plastic circle and filter for your air cleaner bolt the two together wih the hard plastic on the outside and the filter on the inside to the back of your carb. Now u won't have room for the cluch mount that's the thing under your carb that holds the cluch cable you'll need to fabricate a new one and mount it were it will work.u will also need to turn the top of the head were the spark plug faces the front of the bike. U will also need to fabricate a new front motor mount. And weld the coaster brake to the rear axel. And that's it your ready to roll. If that sounds like to much I build them for $500 plus shipping

What did you use for a motor? Use the serch at the top "how to post pictures" would love to see it,thats for the info..............Curt

Bzura said:

Hey maniac - here's a Dolomite that I did with a SBP HD shift kit. The engine barely fit. I had to tap wider holes in the front mount to make it work because it wouldn't fit with a plate/u-bolt adapter. Other than having to buy a longer 5/8" shaft and fabricate a longer arm for the chain-stop, it pretty much all worked out fine.

It's the bicycle equivalent to riding around in a tank. I love climbing hills & riding wheelies around in the dirt in low gear. It takes a while to get up to speed, but it's actually pretty fast.

View attachment 71171

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Is there any way you can post a pic, or elaborate on what u had to on the front motor mount?

Davezilla said:

Those are really cool looking and would make a nice platform for a build, the only issue I see with them tho is the small frame will make installation a bit tricky... not impossible, but tricky like needing some minor cutting and fab work. I did my mountainbike with a 66cc engine and it has a small frame, but not quite that small and there's very little room for the engine so I had to do some fab work to get my engine to sit in the frame the way I wanted it to, it was a tight fit but I got it in there and working, but these frames look even smaller... Here's mine for comparison and you can see there's almost no room behind the carb and I had to get a special intake duct just so I could use an air filter... but it was worth it in the end.

Here you can see it's a tight fit, what you can't see well is the mount tabs on the lower tube that the engine bolts to... Also notice the lack of clearance for an air filter... I fixed that problem since this pic was taken, but this will give a basic idea of how tight the clearances are in a small frame bike.. I really like those fat tire bikes tho and may consider one for my next build anyway...

Click to expand...

hey Dave did u do that chamber yourself, looks really nice