My First MB Project

[MotorBicycleRacing]

It doesn't look like your motor is centered on the front mount but your
pics are small, dark and hard to see what is going on.....

The header of your pipe should be much closer to the front downtube

Do your pedals clear both sides of the motor evenly?

The last pic doesn't even seem to show the motor mount attached to the front
downtube........

 

[pessen]

My front downtube was too big for the motor mount to fit around, plus I have brake and gear lines running down bottom side of the front tube so I didn't want to mess those up.

The motor is secure, I used the alternative mounting method they provided which is the metal plate with 3 holes, one to attach to bike frame, and 2 outside holes to attach to motor. My mountain bike already had holes drilled in the frame designed to attach a waterbottle holder, so I simply used one of those holes to screw the mounting plate into. I did some pretty good pushing and pulling on the motor and there wasn't much give at all.

I am pretty sure the pedals clear both sides evenly, I will check again though. Even so, the amount the exhaust is off is way more than could be compensated for by adjusting the motor.

 

[fetor56]

I hadn't seen that thread before but sounds like it should work. Now I just need to find someone who has a blowtorch, and a vice, and get my bike over there to get the muffler adjusted correctly. I live in an apartment so I am pretty sure I don't have those items laying around.

I didn't realize how many mods and tweaks I would have to make.....not that I mind tweaking and whatnot but I want to ride my MB sometime this year!

If u have no need to "tool-up" or friends arn't convenient u could take it to a car exhaust installation shop....they'll do the job pretty cheap.
You could try cold bending the exhaust but frankly i wouldn't recommend it.....too many horror stories.

 

[pessen]

If u have no need to "tool-up" or friends arn't convenient u could take it to a car exhaust installation shop....they'll do the job pretty cheap.
You could try cold bending the exhaust but frankly i wouldn't recommend it.....too many horror stories.

I didn't think of that. There are several close by so I'll probably give that a try. Thanks for the suggestion!

 

[pessen]

Ready to Ride!

Finally have the motor completely installed. Took longer than I anticipated mainly because this is my first build, though, I only had a limited amount of time to work on it being I am working and in school.....

Anyway, I am hopefully gonna start her up this afternoon......wish me luck!

I'll let you all know how it goes....

 

[fetor56]

Good luck man...if i was there watching u i'de make sure to stand well back.

 

[pessen]

Success!

So, I took her out to the back alley, put full choke, started peddeling and let out the clutch. And.....put put put....stall. Turns out I had to turn the choke down about halfway before it would stay started. Once I did that it ran like a champ!

I let it idle for a little while and then tried to ride it slowly, but had my chain come off twice. Thats why I started out nice and slow. I think my chain is a little loose so I need to take a link or two out.

Anyway, I am sure I will need to do a bit of tinkering before I am fully satisfied with how it is running, but boy was I excited when she finally roared to life!

Thanks for everyone who has given input and suggestions so far, I am sure I will have more questions about tuning the engine for optimal performance so stay tuned!

As Mountainman would say, I am finally riding that thing!

pessen

 

[pessen]

Performance Questions

So, my bike is up and running, but I have a few questions for those of you who have ridden more than I have (which should be just about everyone).

(1) My installation manual says to adjust the screw (~4-1/2 turns) on the carb so that the engine is running at ~1400 RPM. How the heck do you measure that? Is it just by adjusting it until the engine sounds good? I am still new to this so don't quite know if I am running mine at the right speed. It doesn't sound like it is running really fast or anything.....any tips for getting this right?

(2) I initially installed the chain without the additional tension piece, but my chain slipped off a couple of times so I realized it was too loose. I took a link out of the chain but then it was too short and I couldn't get it reconnected. I then installed the tension roller and it works fine, but the cheap one that came with the kit is really noisy and I attract attention just pedaling with my motor off cause it is so loud. Has anyone made a custom tension piece that works well and is quiet?

 

[ENO]

Hey Pessen..ENO (Down Under)..Have you ever thought of extending the exhaust pipe so it sits just under the motor and points backward..I took mine to the Muffler man and paid $30 AU to add a pipe and fit it..I never did like the look of the muffler in the stock shape or the placing. Have attached pic to show result...See ya