Dual front disks

robertpokerplayer · Posted: April 6, 2005, 12:50 pm Post subject: Dual front disks

Has anyone converted their bike to dual front disk brakes? It seem like it would be easy enough, after all the mounting points are already there. Would it be worth it to put the second brake on or would it just be busy work. Also does anyone know why Yamaha didn't sell models in the US with the second brake on the front?

mo650chopper · Posted: April 6, 2005, 6:49 pm Post subject: Re: Dual front disks

I want to do that to mine as well, not for the additional stopping power I just
think it looks better. Have no clue as to why they didn't come that way than the usual reason of
$$$$$$$$$$$$$$ See the following link for info.

www.biker.net/650/dual_disk.htm

robertpokerplayer · Posted: April 7, 2005, 7:49 am Post subject: Re: Dual front disks

That is a great tech peice, and the one that got me interested. I found a place here that I can get the entire front brake system for $50. The only thing that I will have to go out and get is the new banjo bolt, but I don't think that will be that hard. I think I am going to do it. Let you know how it turns out.

yamaha75 · Posted: May 26, 2005, 2:34 pm Post subject: Re: Dual front disks

robertpokerplayer

Hi there i am wanting to fit duel front discs to my 79 xs special. I have a leaking bleed nipple, any ideas of how to stop the fluid escaping?

can you give me the link for the twin setup or does anybody know where I can get a new left hand caliper. I'm in the uk

thanks

jon

timber · Full Member Joined: Jun 16, 2005 Posts: 13 Location: wi

most of the xs750 & up xs had dual disk set ups. they will fit on the xs650. remember that you will need a larger master cylinder also. ask around at your local scoot salvage yard for one of those complete set ups.

verticaltwin · Posted: June 22, 2005, 2:21 pm Post subject: Re: Dual front disks

While at a yard sale a couple weeks ago I inquired about a bike I saw sitting out behind an outbuilding. The couple told me I could have it if I wanted it, turned out to be an xs1100, non-running condition, some parts robbed. Will the whole front end swap over to a 650?

VT

sportydriver · Posted: July 18, 2005, 7:55 pm Post subject: Re: Dual front disks

I bought a cast wheel for a xs750 that had dual disk. The rotors are smaller than on the 650. They compensated by moving the mounts lower on the lower legs. This is actually better because with smaller rotors you end up with less weight. The calipers are exactly the same.

yamaha75 · Posted: July 19, 2005, 1:44 am Post subject: Re: Dual front disks

thanks for the reply sporty driver, i've fitted a master cylinder off a yamaha fz1000 fazer and what a difference it makes, wow 2 fingers to stop, brilliant !!

L.e.m. · Posted: July 21, 2005, 8:55 pm Post subject: Re: Dual front disks

A buddy and I installed an extra disc on the front of my '79 2F. It works ok, but if I was doing it again I probably wouldn't. It does look sexy but I'm more interested in performance than appearance. The braking is better but the brake lines refuse to be properly bled. No matter what we did, the lever is still spongy. Consider all that extra weight hanging out in the front. I would suggest strongly that anyone considering dual discs make 100% sure the rotor, caliper and master cylinder are in first class shape, the brake pads are good, and then add a braided brake line instead of going to the trouble of hanging another disc on the front. Another disadvantage is that both slave cylinders have to be disconnected if/when the front wheel is removed.

Happy trails.

kingwj · Posted: May 15, 2006, 8:04 am Post subject: Re: Dual front disks

I have the dual disk setup using the standard xs650 mastercylinder. I like the feel of the lever, you can grab a big handful of brake and it is easy to modulate. However the plastic resevoir is smaller compared to the 850/1100 mastercylinder. I have the larger mastercylinder but it is for a special, not the standard. I'd like to swap the resevoir but I'm not sure how it is attached. It does not easily pop out but I'm pretty sure it is just pressed in, perhaps with an O ring. Anybody ever done this? I'd hate to destroy a good mastercylinder if I don't have to.

Wulf · Posted: May 15, 2006, 4:34 pm Post subject: Re: Dual front disks

Hey L.e.m. If you still have a spongy lever action then you still have air in the system somewhere. The air bubbles are compressing and not giving you the solid feel you should have. You might try using a vacume pump setup to pull brake fluid through the system to get the last bit of air out. I had to do that on my brothers Toyota truck after we replaced the clutch master and slave cylinders. No matter how much we gravity bled or pump and bled we couldn't get a decent pedal. Hooked a mighty vac up to it and that did the trick. Give me a shout.
Wulf

Wulf · Posted: May 15, 2006, 4:37 pm Post subject: Re: Dual front disks

Hey Kingwj, I wouldn't attempt to remove the resevoir. You really need to just go ahead and mount a larger master cylinder. You can find them on ebay all day long. MikesXS has them at a pretty good price.
Wulf

Phred · Posted: May 15, 2006, 6:35 pm Post subject: Re: Dual front disks

L.E.M., try "speed bleeders", available from most performance parts outlets (Summit Racing, etc.). You can then bleed both calipers at the same time.

chapmanmd · Posted: July 6, 2006, 11:27 am Post subject: Re: Dual front disks

Let me ask you guys this...

I have a 76 Street Tracker that just has one front disk and a braided steel line. I had wanted to put two drilled rotors on it, mainly for appearance, but I can't seem to find the drilled rotors for a 76, rather only for the 77 up. Will the newer one piece drilled rotors mount up to the 76 spoked wheel?

Thanks.

Cafe_Shop · Posted: July 6, 2006, 12:13 pm Post subject: Re: Dual front disks

They will mount to the wheel but your calipers will not be in the correct position for the disk. You will need a newer model fork as well as front calipers. Look around on the net. There are places that will drill rotors for you.

chapmanmd · Posted: July 6, 2006, 3:33 pm Post subject: Re: Dual front disks

Thanks for the info. Now let me ask another question, if I may. Will drilling the rotors make them weaker or more likely to warp? I know that on my race bikes, we used rotors that were cast with the chamfered cooling holes in them as to not cause warpage of the rotor. Am I just making too much out of this and should I just forget it and be happy with what I know works?

Cafe_Shop · Posted: July 6, 2006, 8:32 pm Post subject: Re: Dual front disks

There seems to be a lot of controversy over "molesting" rotors. Some engineers are fine with it, others say it's the worst thing you could do. I'm pretty sure warpage has more to do with the quality of the material the disks are made out of more than whether they have holes or not. I'm speaking form automotive experience. I have drilled rotors on my Jetta. They actually seem to work better for me. Before this set I went through 3 sets of rotors rapid fire due to warpage.

royfisk · Posted: July 30, 2006, 1:56 pm Post subject: Re: Dual front disks

As for trapped air in the system I have found that if you totally seal your system and squeeze your brake lever as far as you can, then put a wire tie to hold the lever in that position over nite usually gets out all the air. when you release the wire tie make sure you check your brake fluid it will go down. I am right now trying to dual disc a 75 front end and have found so far that the original caliper will bolt on to either side of the bike by simply reverseing the upper mounting stud with the upper caliper bolt. Now to find out wether the rotor will be in the correct location or not. I will keep posted.

bigj8550 · Posted: August 1, 2006, 3:05 pm Post subject: Re: Dual front disks

Royfisk please post some pics if you can I am very intrested to know if this works for you. And sportydriver what year of xs750 did that wheel come off of. one of these are sure to take care of my wheel swap brake issues. Thanks

KYLEPRESTON · Posted: August 2, 2006, 10:34 am Post subject: Re: Dual front disks

if you are looking for a good set, try rotors from a FJ1200 I believe it was a 83. I have a set and they fit like stock on my 73tx650.

its nice to have people to talk to for info

cheers Kyle

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