Mongoose Malus BBR - 2 stroke / Sick Bike - shift kit

[Fishfiles]

I was thinking of a smaller tire, but why buy a fat tire bike then, right? It still will be loads o' fun without the shift kit.

Actually 2-2.50 tires would be better for going faster than those big ones. If you were to get it up near 50, there would be quite a bit of tire vibration.

I hear you , I wanted a big tire bike , so dropping tire size would be a waste ----- there are 26x3.0 tires out there , not sure if that would be enough ---as far as moving the engine forward , the shaft of the jack shaft kit is about 1/8 of an inch from the seat post now , so the motor can't go any farther forward

welding extensions where the tire/rim mounts looks like one way to go

I found a 13 and a 14 tooth gear , I ordered both , the original 17 tooth is 3 inch diameter the 14 tooth is 2 1/2 diameter and the 13 tooth is 2.23 diameter ----what affect you'll think dropping 3 teeth will have on performance

 

[Chainlube]

I hear you , I wanted a big tire bike , so dropping tire size would be a waste ----- there are 26x3.0 tires out there , not sure if that would be enough ---as far as moving the engine forward , the shaft of the jack shaft kit is about 1/8 of an inch from the seat post now , so the motor can't go any farther forward

welding extensions where the tire/rim mounts looks like one way to go

I found a 13 and a 14 tooth gear , I ordered both , the original 17 tooth is 3 inch diameter the 14 tooth is 2 1/2 diameter and the 13 tooth is 2.23 diameter ----what affect you'll think dropping 3 teeth will have on performance

I think you would just have to pedal more to get going??? Here you can put your gear count in here, https://electricscooterparts.com/motor-jackshaft-wheel-gear-ratio.html the faster your total speed is the more pedaling you'll have to do.

 

[Fishfiles]

I think you would just have to pedal more to get going??? Here you can put your gear count in here, https://electricscooterparts.com/motor-jackshaft-wheel-gear-ratio.html the faster your total speed is the more pedaling you'll have to do.

That is a cool chart , but , it doesn't take into effect the crankshaft pedal sprockets , when I run the numbers switching from a 17 to 14 tooth sprocket , I come up 75 mph in high and 43 in low

 

[Fishfiles]

So am I thinking about this right : if I change the big gear of the left side of the jack shaft from 17 to 14 to achieve clearance with the tire , then change the inner gear of the two crank pedal gears from 36 to a higher number , could that get the ratio back close to the original ratio

 

[yuckfoo]

On my triple chainring shift kit I too placed a 7 position rear twist shifter on the left handlebar it's right beside of the 3 position front trigger shifter.

The shifting all with the left hand will be done like this:

1(1-3) uphill and pulling
2(3-5) around town general use
3(5-7) open road use.

The reduction range is 66.79:1 to 16.25:1

The 7 position shifter is just like your throttle now you twist down to go faster. You twist up to go slower.

View attachment 104440

I have a Mongoose. I left my shifter on the right side. All I did was change the order of the shifter and the brake so that the brake was closer to the throttle.

 

[yuckfoo]

Looks like the Sick bike shift kit is going to stop me from using the upgrade aluminum head , and I cut the top mount off the bracket to be able to squeeze the engine in , going to have to do some welding or bolting up of a redesigned upper mount , it took a lot o drilling and grinding for the shift bracket to bolt up , the bolt holes were too small ---

the front motor mount stud just miss to fitting the frame by 1/2 a hole , in the pic you see one stud in the engine , the other side don't make it

as it is in the second pic I could squeeze the upgrade head in , but when I use the front motor mount adaptor plate the short head just barely clears the upper frame tube

The original sickbikeparts shift kit motor mount was designed for 6 mm bolts. They now make one for 8 mm. I did some grinding on mine as well as enlarge and reshape the side holes for wrench access.

 

[yuckfoo]

Hi to all , I'm new here to the forum and thanks for having me ! Hope I can contribute and gets some info ... I'm a heavy equipment mechanic by trade and my main hobbies besides fishing is building and riding 4 wheelers , I am into the old school Honda 300s and 450s , if any of you'll into 4 wheelers and mud riding , I hang out at ATVHonda.com ---- newest hobby is motorized bicycles , it is addictive

I am starting on my second motorized bike build , my first build is a E-zip electric bike that the electric took a dump , the E-Zip frame and wheels are heavy duty and I hated to let the bike go , so I converted it to a 2 stroke , I'd say that build is a success , it runs great and is fun to ride , but I live rural and there are a lot of dirt roads and I wanted something more suited for it , a motor cross bicycle for say , LOL -----

So I am starting a Mongoose Malus big tire bike build , just got the BBR 2 stroke stage 4 engine kit and a Sick Bike shift kit in the mail ---- I thought I did a lot of research on it , but apparently not , as right off the bat , the crank bracket insert that accompanied the kit seems not the right size as the Mongoose has a very wide crank bracket to start with

So my questions are about setting up the crank for the Sick Bike shift kit , any links to threads or videos would be greatly appreciated

Here are some pic of my E-Zip ---- and the new project a Mongoose Malus which I got from a flea market for $100 , the guy wanted $200 for it and after he didn't sell it for 2 weeks he took a $100 , think I got a good deal
View attachment 104348

I've been working on a Mongoose Dolomite. I was just test fitting the engine with the sickbikeparts shift kit when I realized the down-tube is too wide to install the exhaust side motor mounts. Have you gotten very far with your Malus? I know people put engines on these fat bikes, but my tube seems to be a little bit too wide to allow the threading of both bolts. I can get one side or the other but not both.

 

[Fishfiles]

I got the Malus not the Dolomite , they do look similar , your model looks like you got more room than mine ----- I cut the adaptor mount and used 1/2 of it , had to use allen pan head bolts as the hex head bolts was hitting the fame and I couldn't even get motor in , you can see how much I scratched it up cramming it in , I have to force it in


I finally got the sprocket back from the machine shop getting cut thinner , it was thicker than the chain and the front engine sprocket , think it was for 415H chain not 415 , went from 17 tooth to 14 tooth , never did find a 16 or 15 , can't wait to see how bad it messed up performance

 

[yuckfoo]

I got the Malus not the Dolomite , they do look similar , your model looks like you got more room than mine ----- I cut the adaptor mount and used 1/2 of it , had to use allen pan head bolts as the hex head bolts was hitting the fame and I couldn't even get motor in , you can see how much I scratched it up cramming it in , I have to force it in


I finally got the sprocket back from the machine shop getting cut thinner , it was thicker than the chain and the front engine sprocket , think it was for 415H chain not 415 , went from 17 tooth to 14 tooth , never did find a 16 or 15 , can't wait to see how bad it messed up performance

Now that I'm test fitting everything with the all the clamps it seems I no longer have enough room with my 17 T sprocket. The chain is about 1 mm away from the tire if I'm lucky and my engine seems to sit twisted slightly so that the left side of the sickbikeparts motor mount is closer to the tire than the right side. It looks impossible and yet I've seen videos of them.

 

[Sidewinder Jerry]

What kind of rear derailleur are you going to use?