Intrepid Wheelwoman
New Member
Your experiments with motor bicycles are original and definitely don't follow the ordinary ways of doing things lowracer. Wonderfully inspiring stuff and moreso because you do all this without welding anything.
DIY Shift Kit Project--'The Shifty Beast'
- Thread starter lowracer
- Start date
lowracer
New Member
Here is a pic after I cut it down & test drove it a bit.
The length now from the engine to the begining of the expansion chamber is 14".
The length from the engine to the largest part of the expansion chamber is 21".
I can definitely feel the power now, its feels very responsive and sounds mean.
I'm going to finish covering the 'possible leg burning section' with header wrap and add another rubber mounted muffler hanger attachment point for good measure.
I have a hunch that by going straight pipe to the expansion chamber there is a beneficial effect for the sonic backwave towards the piston...
I'll have to hook up the trusty old RPM meter again to confirm my suspicions.
-Lowracer-
The length now from the engine to the begining of the expansion chamber is 14".
The length from the engine to the largest part of the expansion chamber is 21".
I can definitely feel the power now, its feels very responsive and sounds mean.
I'm going to finish covering the 'possible leg burning section' with header wrap and add another rubber mounted muffler hanger attachment point for good measure.
I have a hunch that by going straight pipe to the expansion chamber there is a beneficial effect for the sonic backwave towards the piston...
I'll have to hook up the trusty old RPM meter again to confirm my suspicions.
-Lowracer-
Attachments
lowracer
New Member
Thanks Maniac!
This 'Above Top Tube Mount' is really working out great especially since relocating the pipe to the rear of the bike. It was too noisy down in front of me...
I might get a Goped tank and mount it on the triple clamp fork to allow more 'getting aero'.
We will see.
-Low-
This 'Above Top Tube Mount' is really working out great especially since relocating the pipe to the rear of the bike. It was too noisy down in front of me...
I might get a Goped tank and mount it on the triple clamp fork to allow more 'getting aero'.
We will see.
-Low-
lowracer
New Member
Depending on the bike, where the seat tube and top tube are located in relation to eachother, this 'Above Top Tube Engine Mount' could work on most bikes.
Here are a few pics of items to make an easy install.
1- cut square steerer stem (attached forward to seatpost via a shim (found on eBay)
2- some 'L' angle aluminum or steel
3- pocketbike tranny
4- HD clamp (avail on eBay in most sizes)
5- old inner tube wrapped around the frame and taped (protects paint & metal)
I would also reinforce the angle aluminum tranny mount with some scraps of metal to another fixed point for additional support (I dont trust clamps much)
Cheers,
-Low-
Here are a few pics of items to make an easy install.
1- cut square steerer stem (attached forward to seatpost via a shim (found on eBay)
2- some 'L' angle aluminum or steel
3- pocketbike tranny
4- HD clamp (avail on eBay in most sizes)
5- old inner tube wrapped around the frame and taped (protects paint & metal)
I would also reinforce the angle aluminum tranny mount with some scraps of metal to another fixed point for additional support (I dont trust clamps much)
Cheers,
-Low-
Attachments
Last edited:
16v4nrbrgr
Active Member
Looking great Lowracer! I bet you could find a dirt bike plastic tank that would fit over the motor and exhaust pipe inside the 'tunnel', an aluminum heat shield with an air gap will keep it from melting.
lowracer
New Member
This has nothing to do with 'The Shifty Beast', but I scored this scooter on CL for $20 & originally bought it just for the wheels, but it turns out to be a pretty nice full suspension platform just begging for a gas engine conversion...
I am also working on a 2WD bicycle conversion into a FWD pedal recumbent lowracer with a midship gas engine shifting thru 8 gears at the rear wheel...This one will be interesting.
-lowracer-
I am also working on a 2WD bicycle conversion into a FWD pedal recumbent lowracer with a midship gas engine shifting thru 8 gears at the rear wheel...This one will be interesting.
-lowracer-
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Albula vulpes
New Member
Lowracer,
How do you like the mitsubishi tu43? Did you get it off of a brush cutter blow out sale on ebay? Do you like it as well at the tanaka pf-4000? Thanks
How do you like the mitsubishi tu43? Did you get it off of a brush cutter blow out sale on ebay? Do you like it as well at the tanaka pf-4000? Thanks
lowracer
New Member
Av & d_g,
There is no comparison here...
The Tanaka PF4000 is a much stronger engine.
I had the Mitsubishi TU43 & a Tanaka PF3300 on a similar scooters & the smaller Tanaka ran circles around it.
Now dont get me wrong, the Mitusbishi is a good reliable engine, just not a performance model ...in fact it behaves like a 4 stroke & would benefit considerably by adding a proper length expansion chamber (as would any 2 stroke).
The Tanaka PF4000 with a pipe is one bad super-reliable mama jamma.
I am loving the Tanaka 47R which is still on 'The Shifty Beast'.
Its too cool going thru the gears, on the boil, on the pipe.
It sounds like a motorcross dirtbike with its super-close ratio transmission...
Check out my latest build using a Tanaka TC-47 (not the R)
http://motorbicycling.com/showthread.php?t=52694
-Low-
There is no comparison here...
The Tanaka PF4000 is a much stronger engine.
I had the Mitsubishi TU43 & a Tanaka PF3300 on a similar scooters & the smaller Tanaka ran circles around it.
Now dont get me wrong, the Mitusbishi is a good reliable engine, just not a performance model ...in fact it behaves like a 4 stroke & would benefit considerably by adding a proper length expansion chamber (as would any 2 stroke).
The Tanaka PF4000 with a pipe is one bad super-reliable mama jamma.
I am loving the Tanaka 47R which is still on 'The Shifty Beast'.
Its too cool going thru the gears, on the boil, on the pipe.
It sounds like a motorcross dirtbike with its super-close ratio transmission...
Check out my latest build using a Tanaka TC-47 (not the R)
http://motorbicycling.com/showthread.php?t=52694
-Low-
lowracer
New Member
http://www.ebay.com/itm/49cc-Super-...aultDomain_0&hash=item19ea712960#ht_60wt_1084
This is the pipe, cut the header, get some flex pipe @ Lowes (or bend some conduit if you have a bender), I used a straight 'ceiling fan drop pipe I found @ Lowes on sale for $1.00), some header wrap on eBay & you're good to go...get 12" of header before expansion begins on chamber...
Cheers,
-Low-
This is the pipe, cut the header, get some flex pipe @ Lowes (or bend some conduit if you have a bender), I used a straight 'ceiling fan drop pipe I found @ Lowes on sale for $1.00), some header wrap on eBay & you're good to go...get 12" of header before expansion begins on chamber...
Cheers,
-Low-
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Albula vulpes
New Member
Lowracer,
Are you able to tell that much difference in the Tanaka 47r and the Tanaka Pf-4000? There might be an opportunity for me to pick up a Tanaka Tc 47 Type R that has low hours on it or a brand new Tanaka Pf-40000. What would you go with and why. Thanks for your advice.
Are you able to tell that much difference in the Tanaka 47r and the Tanaka Pf-4000? There might be an opportunity for me to pick up a Tanaka Tc 47 Type R that has low hours on it or a brand new Tanaka Pf-40000. What would you go with and why. Thanks for your advice.
lowracer
New Member
AV,
Well,
40cc vs 47cc
2.2 hp vs. 2.8 hp
1.5 ft/lb vs 2.03 ft/lb torque
When I ran both engines on a friction drive there was little difference in overall 'feel' but the 40 got better fuel economy.
On the shift kit bike the 47r definitely is more powerful.
Both engines greatly benefit by replacing the std muffler can with a 12" header connected to a pocketbike expansion chamber.
I like both engines and own both engines currently.
IMHO these Tanakas are better than the higher powered high compression Chung Yang 46 or CAG pocket bike engines. Engine life suffers when you ring too much power out of these little engines. If you need a race engine then yeah, but for daily drivers go with Tanaka. If you can get the 47r in excellent low hour condition for the right price then snag it (since there aren't any new ones being made now). I just bought a new Tanaka 40 for $220.
-Low-
Well,
40cc vs 47cc
2.2 hp vs. 2.8 hp
1.5 ft/lb vs 2.03 ft/lb torque
When I ran both engines on a friction drive there was little difference in overall 'feel' but the 40 got better fuel economy.
On the shift kit bike the 47r definitely is more powerful.
Both engines greatly benefit by replacing the std muffler can with a 12" header connected to a pocketbike expansion chamber.
I like both engines and own both engines currently.
IMHO these Tanakas are better than the higher powered high compression Chung Yang 46 or CAG pocket bike engines. Engine life suffers when you ring too much power out of these little engines. If you need a race engine then yeah, but for daily drivers go with Tanaka. If you can get the 47r in excellent low hour condition for the right price then snag it (since there aren't any new ones being made now). I just bought a new Tanaka 40 for $220.
-Low-