Motobecane 50VR

Boy, I work slow.
May 20, 2010, 5:49 pm
Filed under: Frame, Motor

Just to let you know I’ve been working. I fabbed up a mount for the front brake caliper, worked out a ball joint setup for the Gilardoni and mounted the exhaust. Also worked out a different mounting situation for the carburetor, thanks to good ‘ol Chris Rice. I might have this running by Bomb Prom yet. I’ll post a more detailed update later.


Saturday Night
April 25, 2010, 12:32 am
Filed under: Relaxation

Who’s ready to race?

Finally Coming Together
April 23, 2010, 10:07 am
Filed under: Frame, Motor

Really sorry for the lack of updates lately. ¬†That said, I’ve been busy.

When I last updated, I mentioned that I messed the bracket up and would have to cut and re-weld the top portion of it to move the motor 7mm toward the variator side. What I ended up doing was just hacking the mounts off and welding in a piece of steel across what was left and fabbing up two new mounting tabs for the top. The motor is pretty much in the right spot now (its about 2mm off still…not sure how big an impact this will have) but I’m worried about the welds where the new part of the bracket attaches to the old. I didn’t really have room to get in there and reinforce them the way I would have liked so I’m a little concerned that it might break there now. The welds are good but we’ll see. Speaking of welds, do your best to ignore the welds that secure the reinforcement plate to the upper mount. They were completed hastily.

Space has been pretty tight overall when it concerns fitting the motor into the existing mounts on the frame. You can see how closely my bracket comes to grazing the lower part of the motor mount in this pic. This ended up being a real hassle and makes getting the motor onto the frame particularly difficult. Getting that long bolt through there and into the spacer in the variator side mount is really tricky and frustrating since all that stuff is so close together. You’ll also notice that I ended up having to nix the tabs that were there for the sidecover mounts.

Here you can see how close the head comes to bumping the frame. I still might need to shave some more off the back half of it. Overall though, its waaay clean and pretty much went together exactly as in my head.

I had to cut the Doppler spring’s mount on the engine side to squeeze it into the narrower AV7 bracket, no biggie. Speaking of Doppler, that spring really sucks. So does the clutch pulley, and the ER3 is kind of chincy too. I don’t know where I got off expecting motorcycle or automotive quality parts but I was clearly off the mark. I guess that’s what I get for messing around with toys.

With all this talk devoted to mounting, you’ve probably noticed that I’m using Peter’s engine mounts. These are notorious for both their bad rep and for shaking your bike to pieces. However, I’ve used them on my daily rider for the last 3 years over however many thousand miles and I really like them. Sure, they vibrate more than stock…such is the nature of poly bushings but other than that, they’ve worked excellently for me. Plus, I figure the less that the motor moves around due to flex in the bushings, the better.

Here’s the bike as it currently sits. I might look at other intakes. I’ve never really been too crazy about that Doppler intake and I feel like it sticks the carb out waaay too far. Also, I’m not using that air filter. The¬†front forks are the hydraulic EBRs from a Tomos Revival. They went on super easy and I used a combination of Motobecane, Puch and Tomos hardware. The front rim is a 17″ from a Honda CR80. The seat, as I’m sure you’ve figured out is that really ugly Peugeot 103 seat that no one can figure out how to put on a bike without it looking out of place. I don’t think it looks terrible on here…just weird. Maybe too big but too short at the same time? Oh well, it’s light, comfortable, easy to mount and best of all it was free! I painted it with some fabric/vinyl paint and the results were honestly better than I expected.

I didn’t have an acceptable Motobecane rear wheel, so I laced a Moby hub into a nice Puch rim. The shocks were an ebay find and are pretty heavy duty. I think they’re 315mm. The extra height is nice and the bike’s stance feels good but I’m thinking its too high in the front. I intentionally used longer shocks and forks to give the pipe a little more clearance but the front sits about 2″ higher than the back. I might cut those forks tubes down a little bit and bring it down. I left the swingarm shitty because they always get shitty anyway. Also, forgive me for not putting that other chrome badge and decal on there for you.

Not much left to do at all! Hope this keeps you guys satisfied for a minute.

I know, I know.
March 28, 2010, 2:08 pm
Filed under: Frame, Motor

I’ve been lagging on updating. I had to take some time out to replace the starter on my car. My bracket is still all hacked up waiting for me to re-weld it. Should be finished tonight or tomorrow. In the meantime, here’s a little sneak peek.

Dig my doggie blanket.

Almost Finished
March 19, 2010, 7:35 pm
Filed under: Motor

Motor is all together. Port timings are right. Everything clears. I need to tweak my bracket a little bit though. I mocked the whole thing up and the motor needs to be moved about 10mm toward the clutch side so that the belt lines up properly. I tried flipping the ER3 and that kicks it out waaaaay too far. Kind of a hassle to have to go back and cut and re-weld that bracket but it won’t take too long.

Mounting Bracket
March 8, 2010, 3:43 pm
Filed under: Motor

I’ve got a ways to go on this thing, but you get the idea. No, the welds aren’t wonderful and yeah its might be too thin, but we’ll see. I’m pretty confident it’ll hold up but if it breaks it breaks. I can always make another one.

Diggin’ It
March 4, 2010, 3:13 pm
Filed under: Motor

Made a decent amout of progress in the last couple days. The bottom end is all together, a little tight for my tastes but I’m sure it’ll loosen up after its been run a couple times. Going to head to my local bearing shop before work this afternoon to see if they have a 16mm OD 12mm ID needle bearing for the connecting rod.

I also designed a bracket to support the motor like I was talking about in my last post. I got to thinking about brackets bolted to the case instead of using the cylinder head to carry all the weight of the motor and the forces it undergoes during variation a while back but initially ruled it out because of the tight clearances involved in doing this and because I thought it would interfere with the intake. After talking with Nate Bandit and mocking it all up with just a hole through the cylinder head, I decided to go back to the case mounted bracket system. Shown in the picture is the lower half of it mocked up with a cardboard template. There will be one of these on each side with the lower spring mount bolted on top of it instead of vise versa like in the pictures. There will be a brace bar welded between the two lower mounts to which I’ll weld the upper mounts. There will be a tube bracing the upper mounts with bushings on each side through which the engine mount bolt will run. It might be hard to picture and sound weird…sorry. Its not that bad though.

I’m making them out of this 1/8″ plate of steel.

More later.