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Post by modrocker on Nov 9, 2007 13:48:25 GMT -5
So here goes with my first question: after cruising the archives (and searching other Yamaha specs), it looks like only SR's had a front disc with a diameter of 298mm (11.73in). Is that right? I am gathering parts to double up the front end braking but I am keeping the stock cast wheel. Does anyone know for sure on this? TIA,
Kevin
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Post by StewRoss on Nov 9, 2007 15:31:55 GMT -5
Hi, I've never measured the disc but it sounds about right...I'll measure it later unless someone else has the dimensions. For twin discs, bolt on another standard disc and use an XS250 or similar opposite caliper...easy. You'll need a twin disc master cylinder and I have used a rear brake hose for the other side. Depends on the style you're after...you can also run two braided lines or similar from the master cylinder if you like... These days I favour a larger disc with a 4 or 6 piston caliper...less unsprung weight... SR  |
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Post by fe2cruz on Nov 10, 2007 2:21:05 GMT -5
yup just over 11.5 inches, you are correct:  my forks I believe are stock 35mm and have holes for calipers on both sides. mine just need springs, seals oil & a brace. oh and the money to get all, now that the fine people here have shown where to look. are you going stock caliper too? -c |
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Post by modrocker on Nov 10, 2007 8:48:25 GMT -5
Yes,
I'm planning on using the stock caliper (as soon as I hunt one down). I have a master cylinder, twin line banjo, and associated lines from a Suzuki GS750 that had dual discs and it works.
Eventually I'll convert over to braided SS lines after I have the bike on the road.
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Post by chew652 on Nov 10, 2007 9:11:53 GMT -5
An XS650 caliper will work and because it is normally mounted on the other side on a single disc bike, the bleeder will be in the correct position.
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Post by chew652 on Nov 10, 2007 10:53:46 GMT -5
Discs from other contemporary models will also fit. I have one of these on my SR and a rear from a similar bike on the rear. Virago,maxim, and some xs750 and xs850 have the slotted discs that will bolt right on.The stock sr500 rear is thinner though and some xs650 guys put them on their bikes for the weight savings. ebay item #190083568696
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Post by miker on Nov 10, 2007 11:38:46 GMT -5
Actually the stock SR front disc is thinner than an XS650 disc too, .203" vs .275" on my bikes. If you're going to add the weight of another disc, might as well save a bit.
You can use right hand calipers from a '77 on XS750, XS850, XS1100, XS360/400, XS500, an '81 or '82 XV920RH or RJ, or an '82 XJ650RJ Seca.
Given the extra weight of a two disc/two caliper setup and the limitations of rubber, I think a better idea is to go with a single modern disc and adapter letting you run a modern 4 pot caliper. I believe R1 or R6 brakes will clear if you stick with the cast wheel.
miker
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Post by StewRoss on Nov 10, 2007 15:54:00 GMT -5
Out of interest, some of the other bike discs have different looking holes in the centre as well...check them out first... There are people who have done the R6 conversion onto a standard SR mag front as has been said. My recollection was that they'd made a spacer to take the disc out a little wider. The twin piston calipers are a fair bit wider on the inside. I am using an R6 caliper on my new bike but with a wire front wheel...bit of mucking around to get this right. SR |
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Post by shw911 on Dec 13, 2007 1:25:18 GMT -5
Where can I get an adapter to use an R6 caliper? I have an 81 SR500.
Thanks!
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Post by StewRoss on Dec 13, 2007 1:44:12 GMT -5
Hi, You will have to make it yourself. The R6 caliper is an opposed four piston caliper and so you need to adjust the clearance from the rim spokes...not too hard. Then you must make the adaptor plate for the caliper to the fork leg...not as hard as it sounds. Email me and I can supply you with some pics of one another guy did...fairly self explanatory. sross2@vtown.com.au SR |
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