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Yamaha XS750 Brake Rebuild

20K views 113 replies 10 participants last post by  FranklinMarquette 
#1 ·
Hey everyone! So I'm rebuilding my Yamaha XS750 and have some questions about brakes. I'm new at this so I didn't want to do anything overly complicated but if it is the best and most logical option I am not adversed to it.

My current plan is to repaint and shine up the stock rotors and maybe have them drilled (anybody know someone who does this?). I will rebuild and powder coat the stock calipers and put SS pistons in all of them with EBC kevlar brake pads and HEL SS lines. I was thinking maybe the Yamaha R1 front and rear master cylinders to pair with this but wasn't sure ... if anybody has any suggestions I'd love to hear them.

It would be close to if not more than $100 to rebuild each caliper. Is it worth it? Or should I go ahead and replace the rotor/caliper combo with something else? The only thing I don't like about that is that I could not find any easy swaps and don't really want to start having to machine parts to make things that aren't supposed to fit fit.

Thanks for the help!
 
#2 ·
It would be close to if not more than $100 to rebuild each caliper. Is it worth it? Or should I go ahead and replace the rotor/caliper combo with something else? The only thing I don't like about that is that I could not find any easy swaps and don't really want to start having to machine parts to make things that aren't supposed to fit fit.
$100 per caliper is par for the course and honestly it's cheaper than buying a new caliper (Brembo F08s are $130 a caliper and then you still have to figure out how to mount them). I am sure you could get a used caliper but then again you are in the same boat - you should rebuild them before use.

As for the R1 masters - well it is the size of the piston in the MC that makes the most difference not the source. I think the master cyl upgrade for the XS bikes is a 10mm piston for a single caliper setup. I believe dual discs use 14mm. The size of the piston will be stamped on the bottom of any master.
 
#4 ·
That bike looks amazing Steveo! I get what you're saying though as far as the price goes ... for now i'll go with a rebuilt stock setup and if I don't like it then i'll upgrade. Is the HEL stainless brake line kit for the XS750 at a price tag of $200 the best out there? Or is there a better option for SS lines?

Thanks again!
 
#5 ·
You would be better off scrapping the entire front end and replacing it with one from an FZR600. Even brand new the stock brakes were marginal at best. There aren't any calipers readily available which will bolt onto the 750 forks without adapters. The FZR will be close to a bolt up deal, the only issue might be the length of the steering stem. The other issue is that the XS wheels are very narro and very heavy. Using the FZR front end and wheel gets you a decent front tire, but doesnt match the poke pattern of the rear.
 
#7 ·
Yep I'm using FZR600 on mine, the FZR calipers started to leak so binned them for some 2005 R6 ones (cheaper option and better) and levers and MS, huge improvement. Stem is a little long, I had a spacer but I'm removing it to fit the top clamp lower as it sits to proud and ruins the lines so next job on the list. Land vehicle Vehicle Motorcycle Car Motor vehicle
 
#6 ·
Steveo..

Lovely... any pics of the rear sets up close, a ride to the coast on my XS this weekend and I have finally given in to the fact it needs rear sets!!
 
#13 · (Edited)
Okay so I did some adding up and found that it would be about $400 to refurbish the front calipers ($200) and put race tech emulators in the forks ($200). Now the forks look really good so they probably don't need anything ... I could for now just put them back on so I can get the bike running sooner.

Or ... I can buy an entire front end for a 08-16 R6 for around $850 on eBay. That includes the MC, switches, throttle, forks, calipers, levers, triple trees, and clip ons. Is the R6 suspension longer, shorter, or the same as the XS750? Does the R6 rotor fit the XS750 bolt pattern? I've found many XS750 builds just using the rebuilt stock setup but by the time i'm done rebuilding and buying the extra stuff that a R6 front end would include its going to be close to the same price. I've found many R1 front ends as well ... they look similar what's the difference? Found a set of used FZR600 rotors on eBay for $60 ... is it okay to buy used or is there a better new option out there?

Also i'd like to put on a XS400 wheel but the XS400 only had a single front disk. How would I mount dual FZR disks on it? I've seen some builds that have done it so it is possible.

R6 front end:

http://www.ebay.com/itm/08-16-YAMAH...1a5a00c&pid=100005&rk=1&rkt=6&sd=262916873748

FZR600 rotors:

http://www.ebay.com/itm/Yamaha-FZR-...668907?hash=item4b1197332b:g:-JwAAOSw9GhYm4mv

XS400 wheel:

http://www.ebay.com/itm/1981-Yamaha-XS400-XS650-XS-400-Y622-front-wheel-rim-18in-/232288847341
 
#14 · (Edited)
Okay so I did some adding up and found that it would be about $400 to refurbish the front calipers ($200) and put race tech emulators in the forks ($200). Now the forks look really good so they probably don't need anything ... I could for now just put them back on so I can get the bike running sooner.

Or ... I can buy an entire front end for a 08-16 R6 for around $850 on eBay. That includes the MC, switches, throttle, forks, calipers, levers, triple trees, and clip ons. Is the R6 suspension longer, shorter, or the same as the XS750? Does the R6 rotor fit the XS750 bolt pattern? I've found many XS750 builds just using the rebuilt stock setup but by the time i'm done rebuilding and buying the extra stuff that a R6 front end would include its going to be close to the same price. I've found many R1 front ends as well ... they look similar what's the difference? Found a set of used FZR600 rotors on eBay for $60 ... is it okay to buy used or is there a better new option out there?

Also i'd like to put on a XS400 wheel but the XS400 only had a single front disk. How would I mount dual FZR disks on it? I've seen some builds that have done it so it is possible.

R6 front end:

08-16 YAMAHA R6 FRONT END FORKS SUSPENSION HANDLEBARS TRIPLE TREE COMPLETE

FZR600 rotors:

Yamaha FZR 600 Front Brake Rotors | eBay

XS400 wheel:

1981 Yamaha XS400 XS650 XS 400 Y622' front wheel rim 18in | eBay

If you use a different bike front end, you will either have mismatched wheels or have to machine custom spacers (center and both sides) and different bearings for the new front axle with the old wheel. Then you have to match the bolt pattern (R1/R6 rotors do not match the xs750 wheel). Machine spacers to move the rotors out. If you use a set up with radial brakes, the spacers are going to be about 1 - 1 1/2" wide on each side. If they are axial brakes you can split the difference between caliper spacers and rotor spacers.

The XS400 wheel is problematic more than just the lack of the rotors on one side. First issue is tube or tubeless. The early ones were meant for tubes and tires. the later ones tubeless. Second problem is the bearings for the XS400 were even smaller than the xs750/850. So while you can get different bearings to fit a bigger modern axle on the xs750/850. No such bearings exist to convert the xs400 wheel. So that means having the wheel machined to fit a bigger bearing. Finally, while you are at it, you could throw some more money at it and have the wheel machined for rotors on the opposite side.

If the above doesn't make sense, it will when you start in on the project.

If you think $400 is a lot? The path you are suggesting will be much much much more expensive and time consuming.


Totally not saying it can't be done. It can (I've done it). But if this is your first bike, my question is WHY?!?!?!?!?



Forks might look good, but they could be filled with mud on bikes this old.
 
#16 ·
The only reason I say the forks are most likely okay is because the old man rebuilt them right before he parked it for ten years. My original plan was to simply rebuild the stock forks and calipers but I just want to make sure that the bike performs well. I'm not looking for race level performance ... just a braking system that slows me down and a suspension system that makes the bumps more tolerable. I'm just trying to make a rideable bike out of the old girl. If a rebuilt stock system will do that then that is what I will do. I suppose I just need to get the bike running and then perhaps in the future i'll do some more complex stuff if I'm not happy.

The bike is completely stripped I just need to pick a seat and order a tank (the one I have is the bulbous one off the Special) and then modify the frame.

For now I'm just going the more simpler route ... I'd rather do a simple modest build correctly than try and fail to build a complex one.

Thanks everyone for the advice! As soon as I start building I'll post pictures:)
 
#17 · (Edited)
I'm not sure why people say $100 for caliper rebuilds. Do it yourself. Just disassemble them and clean 'em up. Use some compressed air to pop the pistons out (make sure to us a rag to catch the piston). As long as they are not scored or pitted badly they can be re-used. Even some pitting can be cleaned up with some fine emory cloth. A seal kit is $25 per side, and this shouldn't be a hard to find item since Yamaha had many calipers that were common. Use a light coating of grease an re-assemble. Won't even take you all afternoon.
 

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#19 ·
Regardless of how the U.K. registered bikes, Yamaha considered the 2005 model the R6T. It was a bastard year for the bike. It was much more than just USD forks. The forks rotors and triple treewere 1 year only versions. It looked like other 2nd gen R6's, but, the Frame was different, the radiator was different, the lower fairings were slightly different, shock length was different, ride height was different, throttle bodies were different. I only brought it up because for just about the entire world, if someone orders parts for a 2005 and expects parts to interchange with 2004 R6 parts, they will be disappointed.

i don't know if the U.K. Uses a 17 digit VIN, but if so, I'd be curious what the 10th digit would be on those 2005 bikes with standard forks.
 
#20 ·
In truth I'm no expert but I did own a UK 2005 R6 - just like this advertised.. hence my calipers are 2005 ones according to how the registration works here... an example of a 2005 SL model as proof... Yamaha YZF R6 5SL 2005 *Very Good Condition* | eBay - registered in 2005! I think it was the 2nd half of our registration year in September when they had the revised R6 to the newer version, I actually wanted that model"!

Either way its irrelevant now as the OP is keeping a standard set up... and I have a GSXR 600 lol... but it caused issues in the UK too with the overlap!!
 
#21 · (Edited)
Quick question ... my petcocks are shot ... should I rebuild them or replace them with something like this:

YAMAHA XS400 XS650 XJ700 MAXIM XS750 XS850 XJ900 SECA KZ750 PINGEL PETCOCK

Also I'm replacing my rectifier with a modern one. I found two ... slightly different pricing ... just wondering which is the best buy. Neither has much for a description and they look exactly the same.

http://www.madhornets.com/regulator...1hVZRyRL02kwfBcCqwTDh2pmH0bT9SCymEaArGa8P8HAQ

http://www.electrosport.com/yamaha-xs7508501100-regulatorrectifier.html

Thanks!
 
#22 · (Edited)
Replace the petcock or rebuild without vacuum. The vacuum operated oem ones have been know to leak filling the crankcase with gas. Not necessarily the petcocks' fault...

I have read too many bad reviews of Chinese reg/rec bad out of box.

I've had one from Oregon motorsports that has been trouble free. More expensive but made in America. Not sure if you are US based.
 
#24 · (Edited)
The point of the vacuum operated petcocks was, in theory, to make the operation of the petcock "automatic". It was to prevent someone from forgetting to turn off the petcock when they parked their bike, and having fuel drain out on the ground in the event that a float needle failed to seal properly. The vacuum from a running engine acts on a diaphragm that opens the fuel passage. There are two problems with this theory:

1. A bike does not produce much vacuum when it isn't running, so you have to turn the petcock to "Prime" before you start it, to fill the carbs up. Then you have to turn it back to "On". Kinda negates the whole "automatic operation" thingy.
2. (And this was more critical) The diaphragms have a tendency to leak after time, and this allows fuel to leak down the vacuum line. And instead of draining out the carb overflow....presumably onto the ground......it drains right down an intake port into the engine.

Consequently, much like the Anti-stop, (oops.I mean, Anti-DIVE, front forks).....which were, too slowly, found to act contrary to beneficial fork action during trail braking....they were ditched long before fuel injection came on the horizon.
 
#25 ·
1. A bike does not produce much vacuum when it isn't running, so you have to turn the petcock to "Prime" before you start it, to fill the carbs up. Then you have to turn it back to "On". Kinda negates the whole "automatic operation" thingy.
You would only need to switch the tap to prime if the bike has been sitting for a few weeks or longer - if the bike is started / run every week or so there will still be enough fuel in the bowls to fire it up.
 
#26 ·
Okay makes sense ... does anybody know of a good manual petcock replacement? I saw Mike's XS sells one for the 650 ... will that fit?

Also I found out today that my Yamaha XS750SE is quite different than a standard. The front calipers and forks are drastically different for example. What else is not similar?

My speedo gear drive is seized ... how does one go about taking it apart ... my Clymer manual skips over that whole are (and many others)

Are there any other better, more detailed, manuals out there? I don't have the original one unfortunately.
 
#27 ·
Pingel sell fuel taps that are great quality - but they can be pricey.

Easiest way is to measure the bolt spacing on your current tap and then find a manual one with the same spacing on eBay. Most taps are 34 or 44mm bolt space and a lot of bikes will use the same (think dirt bikes).
 
#31 ·
#33 · (Edited)
If you have the option to go tubeless, the continental classic attacks are an option. They are a modern compound radial tire in classic sizes. Unfortunately they don't have a 90 r19 which probably is closest to the stock 3.25 front.


The stock tires are 3.25R19 front 4.00R18 rear standard. Close to stock in metric size is 90/90R19 and 110/90R18.

If you have the special, you might be looking at a 16inch rear.
 
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