Recent mods to Robin EH035 powered Rocky Mountain RM7

[lowracer]

I altered a few things to make the MB run better & faster.

1- Removed most of the engine shroud for cooling (just left 2 pieces that cover moving parts)
2- Drilled large holes in air filter cover for breathing
3- Removed the muffler cover for cooling
4- Lowered the fork sliders 2" in the triple clamps for handling
5- Strengthened the engine mount & now have the engine additionally supported by the previous gas tank bolt holes.
6- Replaced the fuel line with thicker stronger tubing (previous line was being pinched @ the grommet & would bog the engine at WOT.
7- Removed the gas cap rubber plug doohicky to allow better air/fuel flow.
8- Replaced MTB rear cassette with a new Road cassette
9- Installed new chain & saddle
10- Experimented with different pulley sizing but stuck with original 1.5" engine v-belt pulley
11- Redrilled motor mount to pull the engine back a few inches & more perpendicular with the road (new pics posted)
12- Drilled & bolted together the front drive rim to the rim pulley instead of just being JB Welded (Glued) for added security

 

[Kevlarr]

How do you have the rim you're using as a pulley mounted to the wheel?

 

[lowracer]

Kevlarr,
I have another 26" rim hoop, JB Welded to the 26" front wheel rim. It works great as a Vbelt pulley & gets the gear ratio correct when using a small front v-pulley (1.5"). Make sure you have enough clearance in your fork. The Marzocchi Bomber Jr. T on here has more than enough clearance. I run a 1.25" MTB slick tire up front & it has enough clearance for the belt to not rub the tire.
Alex

 

[happyvalley]

Looking good.

Just a mention on the shroud, it's commonly referred to as a cooling shroud.
If you follow it's design you see it's made to ram forced air from the flywheel fan blades up through the cooling fins on the cylinder and out through the shroud vents. You may have considered this already and still decided to run without it, and if so, good enough.

I've had maybe 10 Robin 35's through my shop and personally I would not run them without it though.

 

[lowracer]

Removing the shroud has helped cool things off at speed. The shroud may be ok while sitting idling or running this engine in an application that has the motor sitting still (water pump/generator), but on an MB cruising along at close to 35 mph, the cooling effect of the air flowing thru the air cooled fins far exceeds what the little flywheel fan is producing. Compare pedalling a bicycle indoors on a trainer with a small fan blowing on you or pedalling outdoors through the air at speed. All older air cooled motorcycles had unshrouded engines?

 

[happyvalley]

Sure thing like I said, if you've considered it, good enough. I just mentioned it because on a number of occasions I've seen it asked where guys were concerned about how it looked or didn't like the color or something.

I've considered both ways but I still prefer to leave them on. The cycloputers I use record an average speed of just a tad under 15mph, that's with 150 hours so far this this year.

To each there own. Good riding with your new bike.

 

[lowracer]

OK, So I decided to do something about my rim to rim pulley system to insure that it wont come apart on me down the road. This was previously just JB Welded together (Glued) & hasn't given me cause for alarm, but a few message board folks have told me to rivet it together for added safety, I decided to buy some 2.5" #10 Stainless steel bolts & nuts & washers. Then I drilled thru both rims 4 times to bolt everything together & have some piece of mind. The only thing that now worries me is that if my drilling has weakened the spoked rim enough to cause a new thing to worry about???...lol

 

[Kevlarr]

I kind of cringed when I read that you used JB Weld BUT even though I think that JB Weld is a poor choice for attaching the rims together there are a lot of better epoxies out there that would be fine on their own. Heck, they're starting to use epoxy to assemble car and truck bodies now, apparently it's stronger to glue the pieces together then spot welds would be.

 

[lowracer]

Just added some pics to my last post of the recent changes to the bike.
-lowracer-