Engine Won't Fit Frame

[Salvor6]

I bought the bicycle first for $45 used. Then I saw the engine kits on Craigslist while looking for bike parts. So I bought an engine kit. The radius at the front motor mount would not fit my 42mm front downtube so I had to machine the front end. Lucky, I'm a machinist and have a mill in my garage. The carb cable will not fit under the top main tube so I had to tilt it. This is supposed to be a 26" bike. Is it a 24" that someone put 26" tires on? Why is the frame so small?

 

[Mr. Minecraft]

Few things to help us out.

1. Bike brand/model etc.

2. Pictures, pictures, pictures!

I always buy the engine first then I actually BRING the engine with me when i go bike shopping and I just check to make sure it all fits.

As far as the carb goes you will need to buy an offset manifold, or even better make your own that fits the way you want it (you are a machinist )

Best of luck!
-Chris

 

[jji7skyline]

To make it easier for short people to swing their leg over the frame and get on the bicycle. Same reason women's bicycles are rarely a proper v-frame.

I've tilted my engine slightly, then taken the air filter off the carb. The engine runs great without the filter (no restrictions, my area isn't dusty either), The spark plug just sits beside the top frame bar.

No problems other than the chain falling off, which I promptly fixed by adjusting the tensioner. No problems since.

 

[TRAX]

The 26" vs 24" are the wheel size measurement. what your looking for when buying a bike that fits you (and or your engine) is the frame size usually measured from the center of the crank to the top of the seat tube. Manufacturers will have different frame sizes of the same 26" or 24" tire bike for different height people. I am short 5'5" so I have a low stand over height (basically the inseam of your pants) or how high the top tube can be so you can stand with the bar between your legs and still be able to have your feet on the ground. it not only makes it easier to get on and off but it's lets say not very comfortable if you have to make a sudden stop and the bar is higher than your inseam My current bike has a 15" frame on 26" wheels the motor is a a very tight fit. like skyline I had to slant the engine forward a bit I used a short intake and I cut down the air cleaner and rear mount to clear the top tube. Buying the engine first and test fitting is a great idea if you can do it but there is also a template on here that you can print and use to check for fit at least for a China Girl. Good luck take some pictures and let us know how you make out.

here's a link to a you-tube video of a guy demonstrating measuring frame size.
http://www.youtube.com/watch?v=nk3CpJ_IPtc

 

[crassius]

cutting a piece of brake-noodle to give a right angle bend into the carb can sometimes help

 

[jji7skyline]

cutting a piece of brake-noodle to give a right angle bend into the carb can sometimes help

Or just install the carb at a slight slant.

 

[Salvor6]

Here is a picture.


I can't load the picture. I get an error that says I already uploaded the pic in another thread.

http://motorbicycling.com/showthread.php?p=457419#post457419