CB100 want alternative front end.

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
I have a 1972 CB100, question is::::::

What complete front fork assemle can I get, that will just bolt right on with very, very little modifications, or no modifications at all?

Thanks all for your input and wisdom, and last but not least knowledge.

Jack
 

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nrcb125

Been Around the Block
I put an XR100 front end (97-03) on my '74 CB125S. BBR makes stiffer front spings them. You'll be able to reuse all the CB100 goodies (brakes, wheel, axle, spacers, steering stem bearings, etc.). I know because I've got a CB100 front wheel in my XR100 forks, all of which is on my CB125S.

What you'll need is a 1980+ CB125S steering stem, and the XR100 forks.

I couldn't find any complete 1980+ CB125S triple trees on eBay... but you could always snag a XR100 triple trees and swap the stem from your CB100 to the XR100 triple. XR100 forks are really easy to find on eBay.

Good luck!

Edit: Added how I know the CB100/XR100 parts fit together.
 

coyote13

Over 1,000 Posts
Interested in this also, you got any news Bud? I've found that the xr100 had the same front end as the xr/crf 100 AND 80. So if we can simply swap our stock CB steering stems into one of those front ends, should be pretty easy.
 

nrcb125

Been Around the Block
surffly said:
A company which makes a lot of aftermarket parts for pit bikes and small cc dirt bikes.

surffly said:
Why xr100 forks?
They have the same axle diameter and many of the parts like the wheel, spacers, steering bearings, etc. can be reused minimizing cost.

surffly said:
Cb350 forks are cheap and larger.
A good set of XR100 forks can be found on eBay for $70-$80. It looks like CB350 forks are about the same. However, the CB350 forks appear to be external spring while the XR100 are internal spring. I personally prefer the internal spring type.

Larger does not mean better. Larger (and also stiffer) forks will transfer more of the load to the frame. This will expose any of the inherent flaws in the CB100 frame. The CB100/125S was designed with flimsy 27mm forks in mind. It's best to keep the forks close to this diameter. 33mm is in my opinion too large for these little bikes.

There is the problem of the 15mm axle diameter for the CB350 forks. This will mean a new wheel. Also, there is no steering stem bearing kit available to readily mount a set of CB350 forks into a CB100 frame.

It looks like bud is trying to do something to the front end with the least cost and modification possible. While a CB350 front end is a possibility it (to my knowledge) hasn't been done. The XR100 front end offers a lower overall cost because of the parts which can be reused and has been proven to work by simply swapping the triple trees/bearings and popping in the forks.

Edit:
It looks like an XL125 or XL185S steering stem could also be used if 31mm forks were wanted. This opens up a few more options in terms of forks and possibly even a more modern hydraulic disc brake setup from a '94+ CB250 Nighthawk. I'd love to see someone do that. Best of luck bud!
 

pacomotorstuff

Coast to Coast
Hell go really crazy and put on one of those leading link, stamped steel front forks from a '60's Honda 90 or similar - be real different for sure! Don't know the difficulty scale, but I'm pondering it for one of my 100cc projects...
Pat
 

whynot

~~~If it ain't raining, I'm riding~~{iii}?~~prost~
pacomotorstuff said:
Hell go really crazy and put on one of those leading link, stamped steel front forks from a '60's Honda 90 or similar - be real different for sure! Don't know the difficulty scale, but I'm pondering it for one of my 100cc projects...
Pat

Heheheheh.............funny.......I do want to be different, but the same. Not that radical, but kewl concept.

Thanks guys for the input and knowledgable answers. At least I have soem ideals and starting points. Just thought having a brainstorming session might bring up some projects that have been tested and trued.

I'm not in a big hurry...............on this thing, so I do have time to juggle ideals.

Jack
 

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