Baja Dirt Bug Project.

[Man Scout Cookies]

I received a baja dirt bug + cash in a trade for a go cart so I immediately started pulling parts together to make the thing more adult friendly. A project and cash to start and finish the project **** yeah!
The bike has a 97cc motor that is absolutely wimpy and the chain is awful loose.

Well I have gotten started I am going to forgo buying a mounting plate and just use the existing plate by drilling it.

 

[2SlickNick]

I bought my daughter the exact same one. I look forward to your progress because I want to mount my briggs and stratton 6 hp in her doodle bug. ...like now. I will probably follow in your steps soon since her 97 cc motor is in need of a carb cleaning. So it is the perfect time to take that out, put in my B&S 6hp, buy the HF for my Murray go kart build., and use the 97cc for my 2 year old's train kart.

 

[Man Scout Cookies]

Well I didn't mean to but I finished putting everything together in a few hours. I'm getting better at this putting a motor on it stuff. Now to fine tune everything to the way I want it.

I just have to find another baja bug frame to put the old motor on now haha.

 

[Man Scout Cookies]

I bought my daughter the exact same one. I look forward to your progress because I want to mount my briggs and stratton 6 hp in her doodle bug. ...like now. I will probably follow in your steps soon since her 97 cc motor is in need of a carb cleaning. So it is the perfect time to take that out, put in my B&S 6hp, buy the HF for my Murray go kart build., and use the 97cc for my 2 year old's train kart.

Sorry I didn't take more pictures. I just wanted to get this done so I can ride it tomorrow. Sticking a new motor on is as easy as tracing where the wholes on the mount are and putting that down on the mounting plate and drilling new holes. Luckily the baja bug uses 35 chain so it is very simple to get a motor and new clutch and throw them on the bike.

However the throttle on the bike does not give a full pull of the motors throttle so I will have to modify it or replace it with something that can get a longer throw with. Also I had to replace the chain tension er (because it was awful) with a piece of 90 degree steel and a skateboard wheel.

Upon reflection I think that one should go with the motor mount adapter plate. The thickness of the plate will put the motor in a more desirable height and position.

 

[Man Scout Cookies]

Bearing change

I've been waiting on parts for the DB I rode it out pretty far and blew a bearing and had to walk it back 30 min or so. Just got my bearings size 62012rs from vxb bearing bought 10 bearings for about 12$ +shipping.

In the meantime I've been repainting the DB from yellow to my favorite color, green.

On my first test runs I've gotten the DB up to 35 mph or about 80 kph.
Any ideas to make my DB hit at least 40? should I use a jack shaft? Or should I try to gleam more performance from the predator 212?

 

[Man Scout Cookies]

Got a new sprocket for the DB. I ordered the OMB doodlebug sprocket adapter and a 60 t split sprocket threw that all together easy.

The bug now goes 45mph and it is a little scary. It feels like the rear end of the bike rises up as I get up to speed. Does this sound right or should I be concerned?

 

[rmm727]

Tire diameter growing with speed.

 

[Moedog07]

If you let the engine breathe by changing the exhaust & air filter and jet the carb it will make a good difference in power without having to open up the engine.