dingy Posted November 30, 2011 Share #1 Posted November 30, 2011 Got a good set of 6 piston Sumitoma calipers for the VenMax today. Came off a 1997 YZF750R Yamaha. 100mm bolt spacing on mounts will match up to the MKII forks on it. Rotors are right diameter, calipers may need shimmed in slightly when I put the VMax front rim on this winter. They were going to need that with the R1's, about 1/4". Off with the R1's, didn't match well with that blue dot !! Gary Link to comment Share on other sites More sharing options...
RedRider Posted December 1, 2011 Share #2 Posted December 1, 2011 You interested in selling the R1's? RR Link to comment Share on other sites More sharing options...
dingy Posted December 1, 2011 Author Share #3 Posted December 1, 2011 (edited) You interested in selling the R1's At some point I will, possibly not until spring when I get a chance to try these out. I may use one of them on rear brake. If they are as good as the R1's I'll be happy, the bling factor will be worth it. New pads aren't cheap for these. Bike wasn't sold much if any in US, so prices are higher. I looked at the numbers in a brake excel work sheet I have and based on caliper diameters and my need to stick with a 9/16" master they should perform as well as the R1's. There's about 27% more piston area than the R1's have. Probaby will be at the point where more is not better with the 6 pots on. Next project is to get a mount so I can put a better caliper on the rear VMax wheel/brake I have on now. It is only a 2 piston unit. Caliper mount arm is an 80mm spacing so that will need to be replaced with a custom unit. Stock Venture arm is impossible to mount with VMax due to offset differences. There is a seller on ebay that makes a billet mount for a VMax that I can tweak to get to work. It will hold a 100mm spacing caliper. Not cheap, but it does need more rear brake. I have a brand new master cylinder for it that is smaller diameter, which will help some. Gary Edited December 1, 2011 by dingy Link to comment Share on other sites More sharing options...
RedRider Posted December 1, 2011 Share #4 Posted December 1, 2011 Gary, Curious about the need for additional rear brake. Mind you, I am a 2nd Gen'er. On the 2nd Gen, the rear brakes will lock up in a heart beat. Don't see where adding braking capacity on the rear will actually help stop any faster. It seems the limiting factor is the friction between the tire and the roadway, not between the caliper and the rotor. RR Link to comment Share on other sites More sharing options...
bongobobny Posted December 1, 2011 Share #5 Posted December 1, 2011 Ahhh Red Rider! Now you see the advantage of linked brakes!!! Gary, you could have always painted over the blue dots! Nice find! Link to comment Share on other sites More sharing options...
Condor Posted December 1, 2011 Share #6 Posted December 1, 2011 Gary, Curious about the need for additional rear brake. Mind you, I am a 2nd Gen'er. On the 2nd Gen, the rear brakes will lock up in a heart beat. Don't see where adding braking capacity on the rear will actually help stop any faster. It seems the limiting factor is the friction between the tire and the roadway, not between the caliper and the rotor. RR That's my thinking too.... Link to comment Share on other sites More sharing options...
RedRider Posted December 1, 2011 Share #7 Posted December 1, 2011 Ahhh Red Rider! Now you see the advantage of linked brakes!!! Ahhh, forgot about that. RR Link to comment Share on other sites More sharing options...
jasonm. Posted December 1, 2011 Share #8 Posted December 1, 2011 5/8 size masters are very common and what most dual disc set ups use. 5/8 is bigger and have a good leverage factor. I have a 5/8 from an YZF1000. Lever angle an all matched perfectly Link to comment Share on other sites More sharing options...
dingy Posted December 1, 2011 Author Share #9 Posted December 1, 2011 Gary, Curious about the need for additional rear brake. Mind you, I am a 2nd Gen'er. On the 2nd Gen, the rear brakes will lock up in a heart beat. Don't see where adding braking capacity on the rear will actually help stop any faster. It seems the limiting factor is the friction between the tire and the roadway, not between the caliper and the rotor. RR That's my thinking too.... So that you guys don't start to contribute to global warming with all this thinking, Lets review. This bike is so far south of stock it thinks summer is approaching. Rear brake was converted about 2 years ago from MKI to a complete MKII setup. This included 320mm floating rotor, quad piston MKII caliper & caliper mount & a 17.5 mm MKII rear master. The brakes were delinked at same time. This year, rear wheel was changed from a stock 16" to a VMax 15". This required the use of a VMax dual piston caliper & modified caliper mount arm, which as been mounted under the swingarm. A 280mm rotor from MKII front was used in place of a VMax rotor to match the front rotors on bike. The rear master was not swapped out at this time and is still the 17.5mm MKII. This combination of master & caliper is not optimal. I have a brand new 15mm MKI rear caliper that I may try, or I have a 12.7mm VMax master I may use. VMax would be ideal, but its mounting configuration is less than optimal. Two ways to fix this, really three but I am not returning it to complete stock. 1st is to increase caliper bore area and 2nd is to reduce master bore area. Not sure which way to go. On this I may go both ways and see which one I like. Gary Link to comment Share on other sites More sharing options...
Condor Posted December 1, 2011 Share #10 Posted December 1, 2011 So that you guys don't start to contribute to global warming with all this thinking, Lets review. Two ways to fix this, really three but I am not returning it to complete stock. 1st is to increase caliper bore area and 2nd is to reduce master bore area. Not sure which way to go. On this I may go both ways and see which one I like. Gary Geeze... Touchy. Link to comment Share on other sites More sharing options...
RedRider Posted December 1, 2011 Share #11 Posted December 1, 2011 Two ways to fix this, really three but I am not returning it to complete stock. 1st is to increase caliper bore area and 2nd is to reduce master bore area. Not sure which way to go. On this I may go both ways and see which one I like. Gary, You are having too much fun. Wish I had time to experiment with things like this. Look forward to seeing your results. RR Link to comment Share on other sites More sharing options...
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