Felt Like A Good Time To Swap Engines

Here's my latest incarnation. Swapped the Subaru Robin EH035 engine for the 97cc Lifan 2.5 HP engine on the downhill MTB. It runs out strong & has more power everywhere. Too bad its over the cc & hp limit of State MB laws.
As long as I keep it under 30 & pedal along in high gear, I might fly under the radar.
Anybody know of a good looking readily available 49cc replacement sticker?
-Lowracer-
 

Attachments

  • IMG00361-20110206-1614.jpg
    IMG00361-20110206-1614.jpg
    245.1 KB · Views: 984
  • IMG00362-20110206-1615.jpg
    IMG00362-20110206-1615.jpg
    229.5 KB · Views: 849
  • IMG00360-20110206-1614.jpg
    IMG00360-20110206-1614.jpg
    239.3 KB · Views: 726
  • IMG00363-20110206-1615.jpg
    IMG00363-20110206-1615.jpg
    241.5 KB · Views: 807
I took the new Beast MB out for a spin today down to the local Mexican restaurant to grab a burrito for carry-out after riding the regular pedal bike 45 miles today.
The Lifan 97cc 4 stroke on the RM7 (full suspension) is a really good match. I was able to cruise along at 35mph (my neighborhood speed limit) & wound it out for a few stretches closer to 45 mph. I didnt gear this one too tall like the last one & it is much more driveable in its powerband.
I did see a few police, slowed down a bit & spun the pedals to simulate regular cycling...No Problems.
Now I wonder what a 5-6 hp 4 stroke would be like on a full suspension Downhill MB?...Nah
-Lowracer-
 
I just ordered a Cag type plastic fuel tank & 7/8" handlebar clamps made to hold rear view mirrors on motorcycles. I am going to remove the ugly top mounted fuel tank on the Lifan 97cc engine & mount this smaller black plastic tank to the handlebars.
This will make the engine look sooooo much smaller while taking some weight off the front rack.
Take a look at the 3 pics.
-Lowracer-
 

Attachments

  • Cag fuel tank.jpg
    Cag fuel tank.jpg
    53.8 KB · Views: 306
  • 22.2mm handlebar clamps.jpg
    22.2mm handlebar clamps.jpg
    10.8 KB · Views: 301
  • Lifan engine2.jpg
    Lifan engine2.jpg
    27.5 KB · Views: 329
Last edited:
I'm liking the RM7 build. Reminds me of my old Norco...

Are those Jr.T's on the front? From my experience I would have thought JR.T's would be a bit too soft with the extra weight on the front.
 
Schwinn-Locura,
It is a Jr.T on the front which came stock on this year RM7 (2002 I think).
There is no extra weight on the suspension up front since the engine & rack is mounted on the fork lowers which is unsprung weight & allows the fork to react to bumps in the road.
-Lowracer-
 
Schwinn-Locura,
It is a Jr.T on the front which came stock on this year RM7 (2002 I think).
There is no extra weight on the suspension up front since the engine & rack is mounted on the fork lowers which is unsprung weight & allows the fork to react to bumps in the road.
-Lowracer-

True, I should have thought of that. I feel dumb now. :(
 
BMP Front Friction on RM Flow

I finally got the new tires in the mail today after waiting almost 3 weeks & having the wrong tires sent (which I got to keep for free). I took it out for a spin after pumping them up to 40 psi. I think I like the slight suspension effect these beach balloon tires give (especially at 30+ mph).
-Lowracer-
 

Attachments

  • IMG00390-20110223-1153.jpg
    IMG00390-20110223-1153.jpg
    125.3 KB · Views: 313
  • IMG00391-20110223-1153.jpg
    IMG00391-20110223-1153.jpg
    115.8 KB · Views: 287
  • IMG00392-20110223-1154.jpg
    IMG00392-20110223-1154.jpg
    114.4 KB · Views: 277
  • IMG00393-20110223-1154.jpg
    IMG00393-20110223-1154.jpg
    121.6 KB · Views: 308
Rear engine friction drive

Did a test today w/ engine on the rear again using friction drive, a suspension fork & 5" dropped handlebars. Handles pretty good using this lightweight engine & getting my body weight low & forward.
Here are the pics.
-Lowracer-
 

Attachments

  • IMG00441-20110226-1803.jpg
    IMG00441-20110226-1803.jpg
    143.8 KB · Views: 304
  • IMG00442-20110226-1804.jpg
    IMG00442-20110226-1804.jpg
    151.2 KB · Views: 318
I have spent a few hours pondering the best possible MB set-up. My brand new electric bike has a front motor, but the equally heavy battery hangs out in back. My last gas bike used the GEBE drive with a RS 33.5 in back and I loved it. Hmmmmmm, I wonder what a GEBE both front and back with a pair of RS 25s would be like to ride. 2.2hp, 2 wheel drive, and at 50cc it would be legal about anywhere MBs are legal.
 
2WD bike on the drawing board also

my next build is going to be a fat tired bike with front and rear engine two wheel drive. I'm going with twin Staton 7 speed chain drives. I need to sell some motorcyles to drum up some extra money for this project. I want a "Rokon" like woods trail bike. That big Pugsley bike would be exellant for this application but its really too pricey for me. I have a dual throttle adapter already that ties the throttles together. Staton's have freewheels so one engine can be shut down if I wanted to in some situations. Dual redundancy. But mostly they would be run together. I can't wait to get started on it.
 
I'd love to see some pics of your builds in progress.
I may be selling my Lifan 98cc engine soon & going smaller cc's again. Now which type engine to go with???
-Lowracer-
 
Back
Top