New to DTT, and starting a '73 CB125 cafe build!
- Thread starter nrcb125
- Start date
rupaulpierce
Been Around the Block
thanks for keeping these updates going. i'm trying to figure out my front end, and I think i'm going to go with the XR100 forks too. Does anyone have the a later cb125 triple for me?
rupaulpierce
Been Around the Block
prefect, the lowers are all over, but no uppers on ebay now. Do you need the lower? If they use 27mm tubes, why cant I use the lower I have from my 74 and the upper from a later model? I was going to just go drum with the XR100 fork.
nrcb125
Been Around the Block
rupaulpierce said:
The 1980 and up triples are ever so slightly wider than the pre-1980 ones. The forks wind up being at a weird angle where they won't fit in the uppers. I thought the same thing and only bought the upper and learned the hard way.
Send me a PM and we can talk about shipping for the uppers.
rupaulpierce
Been Around the Block
while we're on the subject, whats the dirt on front wheels... the cb125 has an 18in front if I remember correctly... the xl100 has a 19? Problems running the xl wheel, or pros/cons with their respective drum brakes?
nrcb125
Been Around the Block
I'm no expert on motorcycle dynamics, but a larger wheel will dive into turns slower, and raising the front shifts weight to the back making it also turn slower and more wheelie prone (not necessarily a bad thing ). I think with a 19" front you'd want to lower it 1 1/2" (1/2" for wheel radius plus 1" for fork length) from the top of the XR100 forks to compensate. You could also look into relacing the wheel with the proper spokes for an 18" rim and reuse the CB125 rim. I think the spoke nipples would be re-usable but you could always give http://www.buchananspokes.net/ a call to double check.
). I think with a 19" front you'd want to lower it 1 1/2" (1/2" for wheel radius plus 1" for fork length) from the top of the XR100 forks to compensate. You could also look into relacing the wheel with the proper spokes for an 18" rim and reuse the CB125 rim. I think the spoke nipples would be re-usable but you could always give http://www.buchananspokes.net/ a call to double check.
nrcb125
Been Around the Block
Update:
One of the guys who works in the machine shop at my university said he could make the bracket for me so I'm going that route.
One of the guys who works in the machine shop at my university said he could make the bracket for me so I'm going that route.
Another thought: the rim may be wider which will also effect handling. Same for the hub. You may need to machine some custom spacers to do it. Also having the front wheel wider than the rear could make the handling funky.rupaulpierce said:
nrcb125
Been Around the Block
Update:
Good news everyone! The bracket has been made. I screwed up a few of the measurements however it seems to be workable. But I may be using a different caliper... The Ninja 250 has a 260mm front rotor whereas the CB125S has a 240mm rotor. This makes the Ninja's pads sit a little too close to the edge of the rotor for my comfort and I think with normal use it would warp the rotor very quickly. As it turns out the SV650 has a 240mm rear rotor, so I snagged an SV650 rear caliper from ebay on the cheap. I plan on doing a redesign of the bracket and try to make it work this time.
I took the rim and spokes from the parts bike to my university's sandblaster and spent a few minutes cleaning them up... The rim was usable but had one spot in particular where the rust was a little bit bad. The spokes on the other hand are another story. They're damn near rusted through. I wouldn't feel comfortable using them as coat hangars. If I want to pursue the drum brake, I'd at a minimum buy a complete new wheel (~$150) OR buy spokes and nipples (~$100) and reuse the rim. Neither of this options seems good ($$$).
Also, bills suck. It may be a little while before I post with another update.
Good news everyone! The bracket has been made. I screwed up a few of the measurements however it seems to be workable. But I may be using a different caliper... The Ninja 250 has a 260mm front rotor whereas the CB125S has a 240mm rotor. This makes the Ninja's pads sit a little too close to the edge of the rotor for my comfort and I think with normal use it would warp the rotor very quickly. As it turns out the SV650 has a 240mm rear rotor, so I snagged an SV650 rear caliper from ebay on the cheap. I plan on doing a redesign of the bracket and try to make it work this time.
I took the rim and spokes from the parts bike to my university's sandblaster and spent a few minutes cleaning them up... The rim was usable but had one spot in particular where the rust was a little bit bad. The spokes on the other hand are another story. They're damn near rusted through. I wouldn't feel comfortable using them as coat hangars. If I want to pursue the drum brake, I'd at a minimum buy a complete new wheel (~$150) OR buy spokes and nipples (~$100) and reuse the rim. Neither of this options seems good ($$$).
Also, bills suck. It may be a little while before I post with another update.
theconjuring
Active Member
nice. Im starting to work on mine as well. i have a 73, exact same than yours, and a '74 parts bike.
looking forward to see some progress shots.
looking forward to see some progress shots.
nrcb125
Been Around the Block
theconjuring said:
About those progress shots... There really hasn't been much progress to show.
But, another update:
Still changing my mind every day about what route to go with the front brakes. The SV650 rotor fits well but the bracket is going to have to be more complex so it's cost will definitely go up. I did find a super cheap CB125S front wheel with drum on Ebay and I'm considering saying f%&# it and going the drum brake route now. I'm also starting to get annoyed with not being able to ride. The 60-70 days we've had here in Blacksburg are killing me.
I also managed to pick up some GSX-R1000 rearsets for free so those are going to be mounted to the CB125 somehow.
I mocked them up where the passenger footpegs are and they just feel right. The only issue are the shift and brake rod lengths. But they were free so might as well give it a shot. And I may also be able to snag the stock steering damper from the same GSX-R for free and slap it on the CB125 because why the hell not.That's all for now. Maybe I'll get off my ass and put some current photos up.
Edit:
Here's a current photo of the bike. K&N filter, XR100 forks, 1980 instruments, and no front wheel...
Attachments
rupaulpierce
Been Around the Block
Another bonehead question...
Doesn't the cb350/360 have an 18" front wheel? Could you pick up one of those or is the rim/drum thicker?
Doesn't the cb350/360 have an 18" front wheel? Could you pick up one of those or is the rim/drum thicker?
nrcb125
Been Around the Block
rupaulpierce said:
As best I can tell, the CB350/360 does have an 18" wheel but the axle size is 15mm vs the CB125S' 12mm axle (http://scandalon.com/2009/06/motorcycle-front-axle-diameter-chart/). Not sure about the width, but if it's more than the CB125S' rear wheel the handling will be all sorts of funky. I think a full CB350/360 front end swap would be the way to go if you wanted to use on of their front wheels.
If someone else has experience doing this please let us know.
nrcb125
Been Around the Block
UPDATE:
-Still waiting on more f*#&ing parts.
-Planning on popping the dent from the gas tank this weekend.
-Going to hopefully sand/paint the tank soon
-Looking into painting and/or powder coating the frame. If I can sand blast the frame myself, I might do powder coating.
-Ordered 27mm clip on bars from China, going to have to get a new throttle assembly
On a slightly unrelated note, what is the policy here about bumping your own thread? Should I add updates to the end of my last post or is it okay to add a new post?
-Still waiting on more f*#&ing parts.
-Planning on popping the dent from the gas tank this weekend.
-Going to hopefully sand/paint the tank soon
-Looking into painting and/or powder coating the frame. If I can sand blast the frame myself, I might do powder coating.
-Ordered 27mm clip on bars from China, going to have to get a new throttle assembly
On a slightly unrelated note, what is the policy here about bumping your own thread? Should I add updates to the end of my last post or is it okay to add a new post?
nrcb125
Been Around the Block
Update:
-The clip-ons arrived, one of the shims is too big so they're a no go for now. For the time being I'm using some bars from a Chinese dirt bike which are basically drag bars.
-Put on 13.5" RFY rear shocks. The bike feels a lot more balanced now. Note: They push the swingarm down about 1.25" causing clearance issues. You will have to remove your chain guard and cut your exhaust to make these fit.
-Beginning to rewire the bike and remove all extra wire. This may turn into a home-built wiring harness
-Installed battery eliminator
-Got the front brakes sorted
-Need a new speedo cable
-The clip-ons arrived, one of the shims is too big so they're a no go for now. For the time being I'm using some bars from a Chinese dirt bike which are basically drag bars.
-Put on 13.5" RFY rear shocks. The bike feels a lot more balanced now. Note: They push the swingarm down about 1.25" causing clearance issues. You will have to remove your chain guard and cut your exhaust to make these fit.
-Beginning to rewire the bike and remove all extra wire. This may turn into a home-built wiring harness
-Installed battery eliminator
-Got the front brakes sorted
-Need a new speedo cable
Attachments
Fifty1
New Member
looks good, similar to mine im working on... the guys reading my thread are giving me tremendous amounts of shtt for wanting to go +2" over on the rear shock height, you will have to report back on here if the 1.25" over stock causes you any problems with steering stability, if you dont mind.
rupaulpierce
Been Around the Block
Looks awesome!
Just pulled the trigger on a 1980 front end with drum wheel for $130... right behind you!
Just pulled the trigger on a 1980 front end with drum wheel for $130... right behind you!
