OCD

ive kept the centre stand because of it handiness but im not sure if it should be hitting the chain when its up. wtf have i not set up correctly? Im also having a bastard of a time trying to get the front lines bled of air. Ive pumped at least a litre of fluid through with minor improvement, there are no leaks and braided lines with new crush washers torqued to specs. I took Gos advice and binned the original MC and picked up one off a vfr 750. The brakes work but spongy as . Ttried the zip tie deal over a couple of days . a bit of an improvement but still not good.
cam chain is up for replacement in the new year. i may also have a six speed g/box up for sale or swap once ive tried this one out on the tar.

Normally on these models, the l/h side exhaust (viewed from the rear) - has a small rubber stopper fitted under the exhaust, that the centre-stand sits up against with spring tension when in the 'up' position - this is what stops the c/stand from rubbing on the chain.

When the l/h side exhaust is gone - because a r/h exit 4-1 has been fitted - what you need to do is fabricate a small length of steel that bolts under the pillion peg and drops vertically with enough length to stop the centrestand touching the chain. I have made up a few of these over the years for Z1's etc with exactly the same problem. Even had 1 of them chromed !! Normally a short length (start with 150 mm and reduce as you need) of 25mm x 2mm will do the trick. They look a bit naff unpainted, the other option is to use a much shorter length fitted closer to where the c/stand pivots ?

The brakes......hmmm. What size piston is in the VFR m/c ? It should be stamped or cast somewhere, usually on the bottom. It is probably a 5/8th (16mm) piston ?

There is another way to bleed the air out of the calipers, this has always worked for me. Take off 1 caliper, get a small G-clamp, remove both pads then wind the G-clamp *through* the hole where the inner (floating) pad is normally fitted. The outside (fixed) part of the G-clamp sits on the outer side of the caliper.

Just wind in slowly when the G-clamp touches the piston, and make sure it is centred on the piston. Wind the clamp in until the piston bottoms out.

You need to have the m/c cap off when you do this, and also keep a close eye on the brake fluid level.......keep some rags handy you will need to soak up the excess brake fluid pushed back up the line.

Once the piston in 1 caliper has bottomed out, unwind the clamp and bolt the caliper back onto the forkleg with the pads fitted. Repeat this procedure on the other caliper and then re-fit the pads and bolt the caliper back up to the forkleg.

Go back up to the m/c, and start pumping the lever slowly. Add brake fluid as you need.

What you will have done, is bleed every tiny bit of air out the back of the pistons in each caliper. You *should* find that after a few pumps on the brake lever, you build up pressure very quickly.

This should get you the best pressure possible. One thing to remember - if the brake lines are still the OEM rubber lines you lose a lot of pressure as the old rubber lines will flex internally. Braided steel lines will fix this, or you could take the old lines to a brake shop and get them to make you up some new ones with the same fittings - these will be almost as good as braided s/steel lines but retain the old-school look.....

Keep up the good work

Thanks for that helpful tip, Gos. just got back from up the coast and will give it a go tomorrow. Ive replaced the 30 yo lines with good ridge braided lines but have just noticed the honda M/C has a 1/2 cast on it near the banjo bolt. I would expect this to push less fluid if it is a 1/2 inch piston than the kwacka job but ill see how it is after i bleed the lines. At least ill be a bit more experienced in bleeding lines if i have to swap out the mc again.

just checked the vfr750 owners site. it is a 12.75mm bore but see how it goes. It looks a lot better than the oem and the lever has a bit of adjustment there. I drive a ford at the moment so im used to wooden brakes.

aah OK - 1/2" piston may be a bit small to drive the OEM caliper pistons. You would be better off with a 16mm (5/6th) m/c.

Lever travel is just an equation based on the known properties of hydraulic fluid. The travel measured at the lever is inversely proportional to the square of the piston diameter - basically this means that as the piston diameter decreases, lever travel increases. Going to a smaller piston in the m/c should mean more lever travel to get the same hydraulic pressure at the pointy end. This is why your brakes feel spongier now....the smaller piston is actually pushing less fluid so you need to pull it harder to get the same pressure......If you go back up to a stock size m/c for the stock calipers, you should see lever travel reduced to 'normal' ....and probably a bit less considering that braided lines are fitted

I changed the m/c on the MFP12 from a stock 14mm (9/16th) to a 19mm radial m/c FMD the difference is incredible.....so much more power in the brakes now.

the trouble with the stock m/c is that ive lowered the oem clip ons and it now hits the gauges hence the vfr mc . it was a flea bay bargain so i havent really lost anything except a bit of time stuffing around getting it to fit and pushing a bit of dot 4 through the lines. ill keep my eyes peeled for another mc with a bigger piston. cheers.

yeh those stock m/c from the GPz series were a hideous length. Far too long and skinny, I hate the bastards.

A decent m/c with a 5/8th piston will do the trick looking forward to seeing this little jigger up and running. Many moons ago, I had a mate with one of these - well it was a GPz550 but the mono-shock model.....same basic motor. I recall having an awesome run up the Clyde Mountain - we had swapped bikes and I was riding a mates 350LC at the time - so I was on the 550 and Mick was on the LC ....we had an absolute blast up the hill and all the way through to Braidwood where we swapped bikes back. The little LC was only a few years old at this time, so went like the clappers. We both saw >100mph out of the little jiggers and this was when the coast road was a pile o'shite !!

Happy days......

Im really hanging to get it fired up and going. The wait on some things is killing me. I think ive developed OCD on this bike. BTW Gos where did you score the radial MC from?

I got the radial m/c from local ebay - it was an 07 Gixxer 750 unit from memory ? I think the 600/750/1000 all used the same m/c in any case, at least for that model year - All I was looking for was a cheap radial m/c. They all do much the same job.....

One other option you could use - is a mid-90's ZX6R m/c. These are a normal m/c, but they do have a remote resevoir - it sits in *basically* the same position as a normal round m/c does, but there is a fair bit of room for adjustment as to where you want to mount the remote m/c. I have used one of these on the Black Pearl for years - will grab a photo and bung it up here.

Ebay is the best place to source a m/c .....unless you can jag one from someone here ?

could have scored a cbr 600 08 mc. i find out on monday when i have a look at it. Changed the thread name to reflect how much time im using thinking about this project but it beats sitting in front of the idiot box.

some major developments today. Fitted up a cbr 600 radial m/c yesterday, bled it again,and again, and again but still spongy. (These brakes have more air than a politician on voting day)
New cam chain fitted and the marks line up perfectly. Cam cover fitted and coils hooked up. I cant wait to fire it up.



Pods will be replaced with unifilter set.

cbr 600r m/c



machined up a prototype set of clip ons. agricultural at this stage but still in development.

Normally on these models, the l/h side exhaust (viewed from the rear) - has a small rubber stopper fitted under the exhaust, that the centre-stand sits up against with spring tension when in the 'up' position - this is what stops the c/stand from rubbing on the chain.

When the l/h side exhaust is gone - because a r/h exit 4-1 has been fitted - what you need to do is fabricate a small length of steel that bolts under the pillion peg and drops vertically with enough length to stop the centrestand touching the chain. I have made up a few of these over the years for Z1's etc with exactly the same problem. Even had 1 of them chromed !! Normally a short length (start with 150 mm and reduce as you need) of 25mm x 2mm will do the trick. They look a bit naff unpainted, the other option is to use a much shorter length fitted closer to where the c/stand pivots ?

Fabricated a bracket that comes from the bottom uni track bracket. Its hardly noticeable and works a treat. thanx for the idea ,Gos.

no probs mate

heh those clip-ons look pretty schmick for home-made jobbies

struck a snag. the gbox seems to be caught between two gears.

if its up on the c/stand with back wheel and chain attached - have you tried moving the back wheel anti-clockwise while putting some pressure on the gear lever ? The box won't *change gears* without the actual box spinning .......its the positive stop mechanism built into the box......

tried to move it but it doesnt want to move any where. trotated the engine clockwise by using the 17 mm nut on the ignition end of the crank and it moves freely but when i try it by using the wheel it doesnt want to move more than a poofteenth as if the gearbox is caught etween two gears or something is not meshing correctly.. I can get neutral and it spins freely. I drained the oil and pulled off the output shaft cover to check the paws but all seem good as per manuals. I then went and did the same thing to the spare motor to see if i could replicate the problem but had to go and torture myself at footy training. At least the beers now are easing the muscles and bones at the moment. im going to have a fresh look in the morning. hopefully the shed spirit will be appeased with my consumption of stubbies and all will be good.