Master cylinder bore reaming. Is it possible / advisable ?

[Pasc]

Does anyone know if it is possible to ream a z1000J master cylinder bore that has a couple of imperfections that I suspect is not allowing the seals to seat 100%. The seals and pistons are new so I'm figureing if the bore was reamed slightly larger then the seals may have enough give to open up and do the job they were intended to.

[Garn 1]

Pasc, I don't think the reamer is the method to use, as chatter could be occur which would definitely affect the sealing. The usual method is to hone-out these small imperfections.

If the scouring is such that it can't be honed you can have it sleeved with a stainless steel sleeve and rebored to original size. This is the most common method to save buying a new unit. I have had several done this way. How they hold the master-cylinder to bore & fit these sleeves has always been a mystery to me!
RegardZ.

[RALPHARAMA]

My philosophy is that when it come to brakes I just don't take chances - I want perfect proven technology.

Experimenting to get extra power is fine, but I wouldn't take any chances with brakes - I've eaten my fair share of NHS hospital food and try to avoid it these dayz

[Garn 1]

So Vduk, are you propose that Pasc buys a new master cylinder? Re-sleeving is a proven methodolgy for the refurbishment of these cylinders. I think you may be a little over the top in this case.
RegardZ

[Pasc]

Thanks for the input guys.
Garn, I did consider sleeving but as the bike is never going to be a showroom restoration then fitting a more modern master cylinder might be a less costly. I've been looking at a ZRX1200 front master cylinder on ebay for a reasonable price. I'm just wondering if the lever on the zrx unit would be a straight one similar to the original J unit.
One of the other members mentioned in a post of yesterday that the American cylinders were not quite 5/8ths. The repair kit I fitted to my cylinder a month or two back came from the USA and I'm wondering if this is a contributing factor to the reduced pressure I am feeling at the lever.
Ralphy, I hear what you are saying but as Garn mentioned sleeving is a posssible fix. Had it done about 20 years ago on a T140 cylinder. Thanks for the input though. I'm familiar with NHS food. I was in hospital about 8 years ago with a collapsed lung. Christ, I could have starved to death if it wasn't for the family bringing edible food in. I used to sit there in the bed wondering how a so called cook could manage to boil every last bit of colour out of vegetables.

[chrisu]

ZRX levers are dog-leg ones and span adjustable (dog included for comparison purposes).

see below




just change the other side to match.............


or GSXR ones fit just as well. You can also then go the hydraulic clutch route...... (I've since replaced these with ZRX1200 ones both sides to get mirrors)

[Pasc]

Chrisu, thanks for the pics mate. You've saved me a trip to the breakers.
Well today I swapped over a master cylinder from one of my other bikes that was solid after about 3/4 inch of travel. Put it on the J and it has not improved the brakes one bit. Can pull it back almost to the grip. So now I'm suspicious about the calipers. Really annoying as the calipers have had new seals and been powder coated. I'm thinking the problem is with the caliper mounts and sliders. The calipers seem to not be sliding straight. When I pull on the lever the front end of the calipers seem to be travelling more than the rear end of the calipers.
I'm wondering now if I should cut my losses and not spend any more on it. It might be cheaper to look out for a good ZRX complete front end as I have most of the ZRX rear end to fit to it over winter.

[Pigford]

Pasc....

Whip the calipers off the forks...

Whack 'em back on the discs - whilst NOT mounted on forks...

Try 'em... if OK its the sliders sticking & causing the problemo

Worth a go

[mikey]

Pasc i got a master cylinder on my A2 which i got off bunnyZ off a 80s/90s kawasaki think off the gpz range and it transformed my brakes from being soft and spongy (no matter how much i bled them) to a very firm feel at the lever and the overall feel of the front brakes is vastly improved.

[Pasc]

Mikey, I fairly sure now that it is not the master cylinder that is the problem as I have tried another. I think its the calipers that are not sliding square.

[mikey]

Ok mate hope you get it sorted pain in the arse till you do bled mine umpteen times till i tried that other master cylinder done my head in

[Geoff Meager]

Pasc .. Piggy is right .. that is the best way to find out if the calipers are working correctly ... If its catching / sticking on the pins all it is doing is pulling over the disc !!!

[Pigford]

Come on Pasc.... this is the subject that won me those CMM spanners

[Pasc]

Piggy, I was going to take notice of your past experiences with brakes and remove both calipers and discs but my mot bloke advised against it as it could contravene health and safety regs.
Been out there again today. Taking the brackets off does not improve the feel at all. As I've said previously everything is new in the system, new mc repair kit, new lines, new pistons and seals in the calipers. I've tried a known good mc which didn't help at all. If I clamp any of the 3 lines the mc goes rock solid so thats ok. I am still getting a few very tiny bubbles rising up into the master cylinder which I'm guessing is from the small pockets that are part of the seal construction. Bled them again today and they are getting better but not perfect. I'm toying with the idea of either upgradeing the complete front end now as it's on the cards anyway or I might just upgrade the calipers to a pair of 4 piston calipers (fixed type) for the time being but my local breaker could only offer me fireblade calipers today and I aint putting any onda shite n my bike.

[Rich]

Tie the lever to the bars for a day and see if that improves things - sounds like trapped air to me, do you have a splitter with brake light switch, if so use it as a bleed nipple to see if there is air trapped there.

PS reamers are tapered and rely on passing through the material to produce the correct size hole. Something the design of the M/c will not allow.