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Post by martin125tdc on Sept 21, 2018 19:41:05 GMT
Has anyone been brave or stupid enough to attempt a rear brake conversion on comstar rear wheels??
I'm talking CB125 tdc [1981/2]
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Post by buster on Sept 22, 2018 7:48:04 GMT
I honestly wouldnt know if anyones tried this, it sounds to me like a technical nightmare and for what gain? weight is probably less with the drum set up (at the wheel end thats unsprung weight which massively affects handling) and where you would fit a pedal and master cylinder I dont know (and thats the easy end). getting a sound mounting for the disc must be do-able (somehow) then you need the equivalent of a torque arm for the caliper and remember that it needs to adjust with the chain. and heres me thinking I liked to make life difficult for myself, I wish you the best of luck if you decide to have a go and I’d love to see the result
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Post by martin125tdc on Sept 22, 2018 10:26:15 GMT
thanks for your reply Buster, I think in the modern day we're in it isn't impossible. I was in a MUTT motorcycle shop yesterday and all of their new machines which are either 125cc or 250cc have rear disc, even with ABS>
Most new 125cc are disc, whether its a Honda, YAM, KWAK, SUZI or jap / china import.
I was thinking of a few options to do this:
- New swingarm that has fixings or caliper and pedal already fixed. Not sure which one yet, maybe a CBR125.
- Use my existing Swingarm but fabricate points for caliper and fit new wheel from a CBR125 and a pedal / master cylinder from same.
- Use a VF400 / VF500 rear wheel, swing arm and brakes, hangers.
I have seen a few enquiries on this topic buyt no-one has done this yet.
Id be interested to know possible combinations to get this on, id like to keep the original comstars hence while i have mentioned the VF approach.
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Post by buster on Sept 22, 2018 11:39:03 GMT
I think if it was me and I was dead set on a disc (I think new bikes have to have ABS?) I’d be looking to see if I could mix and match existing parts, your idea of using vt400/500 bits and pieces would sound the most promising to me, could still be a technical nightmare though (shock mount?). but on a more positive note I put cb250rs wheels into my superdream frame with a minimum of fuss, the problem with being the first to do something is its your pocket it hurts if you buy the bits and then cant get them to fit.
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Post by martin125tdc on Sept 22, 2018 12:43:51 GMT
Absolutely mate, if you're the pioneer in experimenting in stuff to reach a target you take the pains and gains to be able to trial things.
So, another option.
- Use a vf400/vf500, vt400,vt500 wheel which has a disc within my swing arm. then fabricate a bracket for the calliper and a bracket for the fluid reservoir and hydraulic arm.
am I right that your comment about the shock month was in regard to changing of the swing arm?
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Post by buster on Sept 22, 2018 15:56:31 GMT
yeah I was guessing that mounting the shocker might be difficult with a full swap of the swinging arm (who knows it might just bolt in). your actual caliper bracket will most likely mount on the wheel spindle, then maybe copy the swing arm from your donor bike for the sliding part of the mounting, if that makes sense
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Post by martin125tdc on Sept 22, 2018 17:00:37 GMT
I have saw a VF500 rear wheel for £25 and a NSR125 [2003] swing arm with brake set up for around same price.
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Post by bodie on Sept 22, 2018 17:41:30 GMT
can I ask why you want to do this conversion is it for looks or just to see if it can be done because it seem a lot of work for something that you will hardly ever use  |
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Post by martin125tdc on Sept 22, 2018 20:23:57 GMT
Hi Bodie, good question, I'm really interested to see if it can be done. it has to be able right? I remember in the 80/90's readers specials where older bikes with sh1t brakes grew new rear dics. I know these where bigger bikes but why should it not be possible on the smaller ones.
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