Pocket Bike Engine Project

[lowracer]

Here are write ups I found of the bike.

http://www.nsmb.com/gear/tbone_banshee_2.php

http://www.nsmb.com/gear/tbone_banshee.php

http://www.nsmb.com/gear/banshee04_11_03.php

-Lowracer-

 

[gera229]

Just for the frame, that's a crazy price!

 

[lowracer]

Gera,
Yeah that would be a good deal just for the frame alone. I was very happy to get the whole bike for $780. Parting it out would bring more than that on eBay. Before finding this bike, I was high bidder on another Banshee Scream, but didnt hit the sellers reserve price. I contacted that seller & he would let me have it for $1150 but I refused.
IMHO, DH MTB's make the best motorized bikes due to strong frames, relaxed steering angles, & huge big hit suspensions front & rear. Just slap a set of fat slicks in place of the knobby tires & hit the road...plus they look bada**
-Lowracer-

 

[lowracer]

I got the Banshee Scream bike today via UPS. Got it unboxed & put together within an hour. This bike is sweet & definitely worth the $$$. I'm sure it will be a good bike to motorize since its so heavy duty. I'll probably ride it a few times unmotorized with the knobby tires on at the local mountainbike singletrack trail. The 8" suspension should soak up anything & everything thrown in its way with finesse.
Will post pics once I get some time this week to take them.
-Lowracer-

 

[gera229]

Lowracer, I need your help if you can, check my thread.

Thanks.

 

[lowracer]

Today, I got my spare leather cruiser saddle installed on the bike & lowered the front end by raising the fork tubes in the triple clamps for better steering geometry. This bike is super comfortable...Here are some new pics (pre-engine)
-Lowracer-

 

[happycheapskate]

Where do you buy Banshee bikes? I'm not into the downhill scene, but that looks great.

 

[gera229]

He bought it off ebay and said it was made in Canada.

 

[happycheapskate]

Yeah the posts showed up after I refreshed the browser. Downhill bikes are not normal mtn bike stuff. They are made for bombing down mountains at 60mph and jumping off stuff that would shatter a normal bike. They are sort of like gravity powered dirt bikes.

 

[lowracer]

happycheapskate,
Yeah, this is a Canadian company based out of British Columbia (the MTB mecca).
Its an overbuilt DH bike made for serious gravity bombing. I sold both my hardtail MB's (Robin Subaru 35cc & Tanaka PF-3300) & with that money will be able to build this one without adding a penny. I've had such wonderful rides on 'The Beast' (Rocky Mountain RM7 DH), that I figured why not have 2 DH bikes motorized. I just installed slicks today on 'The Banshee' (Banshee Scream) & will hopefully find time to install the Cag engine on it soon. I'm not sure if I should start a new thread for this new bike or continue here since it is a Pocket Bike Engine project?
Here are a few new shots w/slicks on.
-Lowracer-

 

[mat_man]

This bike really takes MB to the next level! I notice that the Banshee Scream has 3 wheelbase positions. What is the longest wheelbase?

Thanks
Mat

 

[lowracer]

mat man,
The wheelbase adjustability is almost 2 inches. The bike can run either 24" or 26" wheels & changes to the wheelbase also change the spring rate. The way it is now is in the middle position. I may use the rear position to mount a strut for the rear drivetrain. I got it set up for 8" of rear wheel travel now (thats adjustable from 6-8").
I thought the Rocky Mountain RM series were overbuilt bikes but I think Banshee did them one-up...
-Lowracer-

 

[happycheapskate]

I'm not sure how much difference you will notice going basically straight at around 30mph, but moving the rear wheel 1 cm makes a very noticeable difference when cornering a mountain bike at the traction limits through close trees at "low" speeds. It will be interesting to see what you like for motorized bicycle riding.

 

[lowracer]

I finally got it completed & ready to ride, but I havent filled it up yet w/ fuel since the roads are still wet. I will eventually add the expansion chamber pipe after a few test rides w/the restrictive canister muffler.
Here are the latest pics.
-Lowracer-

 

[lowracer]

I got a chance today to take it out for a few test drives.
It is one sweet ride & feels like a mix between a dirtbike & a small motorcycle.
I have the front part of the DAX 1.5" friction drive unit sharing the mounting point with the suspension arm at the pivot bearings. The housing is free to swing up & down.
The rear part of the housing is tensioned against the tire using a 13.5" heavy duty rubber tie down with hooks. One hook into a friction housing hole & the other into the 3rd unused axle mounting hole. It provides plenty of tension keeping the roller secured against the tire & comes off easy enough should I need to raise the roller.
I havent mounted the expansion chamber exhaust yet but will soon & a few water bottle mounts for extra fuel bottles & a flashing rear taillight...
I also need to get the Tanaka powered Beast back together again too.
I'll probably buy another friction drive unit from Dax but will run a v-belt pulley on the shaft & go back to belt drive.
-Lowracer-

 

[happycheapskate]

Wow, that looks great. I was just thinking about spring tensioners on a Dax and wondering how it would work. Be careful with those tarp straps! Splurge on the better quality ones too (about 3x the price of the bulk chinese ones). If they bust, it might destroy your wheel.

I've done a lot of flatbed work, and those cheap boogers are a necessity for a company driver, but when they let go, aw heck! They can whip you or throw hooks!

 

[happycheapskate]

I've got an idea. You can remove the hooks and replace them with metric bolts! Bolt them to your frame eyelets and the holes on the drive channel, but use wingnuts and rubber washers on those, so you can adjust by using different holes on the drive channel.

A couple of velcro tv-cable wraps can help you secure the top ends if you want to ride with the roller loose on the tire.

If that is too much hassle, you can bend the hooks a little with pliers so they can't spring out of the holes if the straps break. You should still be able to get the top ones loose by rotating the hooks toward the back of the bike and then rotating horizontally.

 

[lowracer]

HappyCheapSkate,
I bought the rubber tie downs at Fastenal & they are the thick heavy duty rubber kind (not the cheap chinese bungee cords). When I installed the tie down, I used a vice grip to bend the hooks thinking the same. The 2nd reason for going with the variable tension idea was that this is a 8" suspension with the rear wheel moving in an arch & tires aren't perfectly round. It seems to be working really well so far, & isnt under much more than about an inch of tension, but if it ever snaps there could be wheel interference. Lets hope it doesnt snap.
-Lowracer-

 

[lowracer]

I installed the expansion chamber pipe today & tool it for a few test drives.
The pipe adds some top end & sounds better but sticks out like a sore thumb.
I may go back to the canister muffler for compactness or route the pipe straight down & change the hanger to fit.
Here is a pic
-Lowracer-

 

[happycheapskate]

If it's only stretched an inch, then it's really unlikely you'll ever even pull them to the maximum stretch length. They should last years, unless the sun dries them out. Just look over them for cracks. Cool build. I want it! I put it on Dax Friction Drive Fan Club as a tribute.

On a hardtail, I bet that would work, same as springs, but better, only it would likely bounce a little and slip a small amount when going over bumps or rough roads. With that killer downhill bike though, and fat tires, bet it will never skip a beat.