a little project for my dirt bike.

[MCRIPPPer]

hey there. here is a part i made for my xr100r. in stock form, it comes with a really bad single sided chain guide(if you can call it that). the chain would derail easily of you turn to the right, if the chain was just a little loose. even worse, is the sprocket is exposes on the back. a few years ago "murphy" got me. i was riding and the front wheel broke free and i fell over to the right. i slid backward and put my left hand out to catch myself. i somehow for my fingertips into the chain/sprocket intersection!!! needless to say it was no good. i didnt ride for about 3 years because my experience was pretty bad. a year ago i decided to give it another chance. im glad i did. since i have a milling machine, i made a real chain guide/guard. it is amde of aluminum and some sort of slippery tough plastic(i think HDPE since it was packaging for a ping pong table) now to front and back are protected and the chain wont come off.



























now the weakest part is the mount to the swing arm .i need to machine a new piece that is thick and weld it on.



i also have some plans for some more parts. this brings me to some questions. i want to make a new shifter that is longer. i also want to make a longer brake arm(drum brakes) for more leverage. fortunately, both the shifter and the brake cam have the same spline. the problem is creating this spline. i do not yet have a rotary table so i cant form them by indexing the piece. i was thinking of buying a used shift shaft or brake cam and sharpening the splines and making a rotary broach. has anyone done a similar thing before?

 

[Rbeckett]

Looks good!!! I was a;ways afraid of the way my chain ran on my YZ250. Always seemed too loose and about to fall off. I never lost the chain, but I was sure paying attention all of the time. The slider block on the bottom is a nice touch and shouls really help in muddy terrain too. Keep up the good work!!!
Bob

 

[MCRIPPPer]

thanks.


luckily my chain only came off once or twice, and it didnt break my flywheel cover.

the real problem is the possibility of debris (fingers!) getting in the junction of chain and sprocket!

i can now loosen the chain a bunch, and push the chain to the side while turning the wheel and there is no way it will come off. the guide keeps it straight. this is the most important part of the chain system for reliability and safety and honda failed! alot of smaller bikes have crappy guides like this.

 

[2manyhobbies]

I like it!)

 

[burnrider]

Very nice

 

[MCRIPPPer]

thanks guys!


any ideas on how to form a spline? do you think another spline could be turned into a rotary broach?

 

[09kevin]

Nice job! If the brake arms and shift lever are steel you can saw them in half then weld a piece of steel on each side to lengthen them, I did that to my bikes with drum brakes.

Kevin

 

[MCRIPPPer]

that is an option. i dont have a welder tho. a nice machined part would look more cool too!