Mean Green- ZXR750 H1 rebuild

ronski said:

Thats funny man. Im totally with ya, everyone I know slags me off cos of my brake bleeding obsession. No matter how long I spend, ITS NEVER GOOD ENOUGH. But Ive reformed myself slightly by now. Just ride the damn thing.

Interested in pics of your bike if you get around to it

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Theres mine, excuse the mess, I like to work surrounded in shit.. Anyway new grips are going on today. Im allergic to non-genuine parts, which is a problem, Kawasaki Australia binned all their zxr750 shit years ago. Most of my parts I have to get from the UK, Germany or the US.

Its a pain in the arse, and double the cost of everything with postage. Ill find some more pics later, gotta run now..

So anyway, believe it or not, my front brakes feel pretty damn good right now. For the first time that I can recall, im actually satisfied with the lever feel. The problem is that I don't know why, and im trying to work out how this could be a bad thing. As I have only really put 30 km's on the new pads, I haven't really gotten into them yet. I can see from the rotor surface the pads are not bedded completely. The only odd thing which may have impacted the improved lever feel is time.. Let me explain.

Just before Christmas, I finish work, for 4 weeks holiday.

Day 1: I go buy front and rear pads, get home, and get to work on the front. The calipers were looking a bit grubby, so I spent ages with tooth brush, cleaning them up, also one caliper is wearing the pads unevenly, so I mess about with cable ties holding the pistons pack and pumping the brakes up to get them moving and I just give them a bit in and out action, none of the pistons had managed to grab a seal and drag it up, and im pretty happy that all four pistons on each front caliper are doing the right thing. Front end, both sides new pads in, I begin the bleeding process, but nothing is going right, none of my hoses is getting a good seal on the nipple and the rotation when I open the valve is causing the hose to slip, I have fluid dripping all over the place, so I switch to the other side, hoping things will improve, about a minute in, I have the same problem, the hose is a tight fit, but the slightest movement and the hose pops off. At this point, I can taste brake fluid, awesome, how did I manage that? I give up in disgust.

Day two: I go out to the garage and survey the mess, there are bits of clear hose everywhere, I can count 4 different one man bleed devices all scattered around the bike. Right, start again, new day and all that. I go hunting for smaller hose, I find a fresh 10m roll of 3mm shit. I cut of a decent length,I put one end in a glass jar and drop in some fresh fluid to cover the end of the hose, I attach the other end of the hose to the bleed nipple and grab my trusty 10mm spanner. I spend forever on each caliper, pushing out old fluid, im careful not to let the lever bottom out on the grip, I had recently read that tip. By the end I have clear fluid coming from each caliper, and the usual spongy lever which I have grown to expect.

I decide to give up for the day, but I will do the old apply pressure on the lever over night and see f I can get some air to rise into the res. I crack the res cap about half a turn and wrap a clean rag around the res. Sure leaving the fluid potentially exposed to air is bad, but I just want to give the air bubbles (if any) a reason to rise. I cable tie the front brakes on pretty hard. I go to bed. The next day I cut the cable tie holding the lever and slowly pump it up. It a little better, but still very ordinary, and history tells me that it will return to shit in a few hours anyway.

The next two weeks I get away for a bit of a holiday I don't go near a brake caliper.

Last Friday I head back out to the garage, and recall how I never did the rear pads, so I give them the treatment. The last thing I do it hang a weight from the rear brake lever and chuck another cable tie over the front brake. Its about 3:30AM by this stage, I forget to crack the front and rear reservoirs open to allow the air out, and I go to bed.

Saturday, around mid day, I go back to the bike and begin to clean out the bobbins on the front rotors at some point I release the brake levers from the cable ties. I pump the front a few times and it suddenly firms right up. Feels good, I assume it wont last. A few hours pass and I have fixed my exhaust leak, time to bed in the front pads I installed 2 weeks ago, and the rears I just put in. I go for a ride, but go easy on them, the front lever feels great, and stays that way. I have owned this bike for about 17 years, and the front brakes lever has never felt this good, something must be wrong. I go looking for problems, one of the front pads isnt making complete contact with the rotor, so I pull the caliper of, and manipulate the pistons in and out for a while, then reassemble, go for a ride, front lever still feels good. The pad still isnt hitting the majority of the rotor, a straight edge across the rotor shows a big low spot. I need new rotors, I guess the new pads are going to take some bedding in to completely clean the surface up. I did not bleed the front calipers again after this.

Front lever still feels good.

Im going to go out there again in a minute and check it again..

Update, I just went out and the front still feels good, its not great, it feels nothing like a new bike, just to be clear, by new bike standards, my brakes are fucked. By ZXR750 standards, they are really good.

Heres a picture of the side of my tool box, the bottom level is some of my bleeding arsenal, my vac pump is not in the pic, and there are a couple different one way valve bleeders which I haven't seen for a while. I also have a jerry can where I dump the old fluid there would have to be 5 litres of old fluid in it, I will get rid of it when i fill the can, only 15 litres to go!!

ronski said:

Very nice bike, looks mint. I like the way youve kept it stock. Mine has gone long past that point. Genuine grips, you're mental.

How many miles up on her? Any problems with valve clearances like mine?

Whats that about not bringing the lever all the way back to the bars when bleeding the lines?.

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Thanks mate, the brake lever thing is a new one that I heard a couple of weeks back, the idea is that in the course of your normal riding, you wont ever bring the lever back to the point where it touches the grip, so there is probably a bit of a build up of shit on the cylinder walls where the master cylinder piston / seals dont normally travel, if that make sense. Im sure its complete overkill and possibly bullshit, but when you spend as much time and effort trying to get a decent feel, then not squeezing the lever all the way to the grip is a small price to pay for a possible improvement, I just put a finger between the lever and the grip so when I squeeze the front brake on to push fluid out of the bleed valve, I could only actuate it so far. My finger would stop it the lever before it could go that extra 15mm or so.. Does that make sense? I know what im saying, but that's a lot of words, plenty of room for error and confusion.

Anyway the bike just passed 72000 k's (its on 72,007) which is just shy of 45,000 miles. When I bought the bike it was in perfect shape, I am the second owner, it had a complete Kawasaki service history, and I kept that going, whilst I rode it as a daily, when I dropped it off for a service, it had valves done per the service schedule, between 2004 and 2010 the bike sat in the garage, not being touched, it was dirty, but it was all there and it was all genuine. When I got it running again, I dropped it off to a Kawasaki dealership and had them rebuild the carbs and do the valve shims. I have never had an issue with the valves, im going to check them myself in the next couple of months, I just need to get some gaskets and shit before I start, buying parts is near impossible here. A few years back Kawasaki had every single part in stock, and never more than 24 hours away at worst, today I cant even get an air filter.

It was my first bike, I have had others over the years but im attached to this one.

Hey Ronski, I have a solution to the brake bleeding issue. I thought I had a decent lever feel what I had was a couple of stuck pistons. I rebuilt my calipers a week or so back, I retained my original brake lines, rotors, and pads. All I did was replaced the seals, including the caliper joint seals, new bleed nipples, also new pad retaining pins.

Somehow I came across a write up on bleeding brakes on a Suzuki forum. Everyone reported amazing results. I thought I would give it a go, in short, it works. The brake lever feels great. I suggest you buy about a litre of brake fluid as you are going to use a lot. I will alos add that I found when there are no air bubbles coming out of the caliper, pump the lever quickly, you will get more, also, stop and tighten the bleed nipple every so often, wait 5 minutes and crack it again, you will get a heap of air out on the first pump after letting it sit for a few minutes. This will change your life.

Anyway, here it is..

Get some teflon tape.
Get some clear aquarium hose. 5mm.
Get a catch bottle for the fluid
Get a wrench to fit bleeders (8mm on most)
Get a phillips screw driver to remove reservoir lid
Get a NEW UNOPENED BOTTLE of QUALITY brake fluid. IMPORTANT!!.
Only takes one person

Put tape on the threads of the bleeders, being careful not to get it so low on the bleeders as to get under them. The teflon tape is important to keep air from seeping past the threads on the bleeders and into the system, as well as keeping the bleeder in place while you pump the lever. The tape is one of the critical parts here. If you wish to not use tape, another option is thread sealant by speed bleeder http://compare.ebay.com/like/3904868...Types&var=sbar. The thread sealant is what makes speedbleeders work really. The hose I am attaching to the nipple of the bleeder once it has fluid in it (after first pump) acts just like the check valve in speedbleeders. Since you need the hose anyway to not make a mess, the check valve is pointless. The key is the sealant on the threads to prevent air seeping past the threads.

Forget the "Pump pump pump, crack.... close... repeat" method. It sucks.

Attach the hose to the bleeders. Run that hose to a catch bottle well above the nipple you are bleeding, so you keep a column of fluid in the hose on top of the bleeder. This column of fluid in the hose on top of the nipples is very important to keep air from going back in the system

Crack the master cylinder bleeder, just enough that you still have some pressure on the lever as you pull it, but fluid is coming out of it also. pump until you get clean clear fluid out of the MC bleeder. I usually run one entire reservoir of fluid through the bleeder. I have also found that letting the lever "snap" back out helps. I am not sure why. It may knock stuck bubbles loose, or cause small bubbles to make bigger bubbles. But it sometimes helps, especially when trying to prime a new system. Re-fill reservoir and move to lower right caliper.

Tap lines lightly with something

Crack bleeder on lower right caliper (with teflon tape on it) again just enough that fluid will pass out of it, but there is some effort at the lever. Run an entire reservoir through it. Close bleeder.

tap on lines again

Repeat with left caliper.

Repeat at all three bleeders, (meaning do this TWICE at EACH bleeder) using about one full reservoir at each bleeder.

remove all hoses and catch bottles. Clean up and ride.

Brake bleeding problems? Look here, fail proof bleeding : Suzuki GSX-R Motorcycle Forums: Gixxer.com

Hey y'all... There's no way after reading every message in this thread that i was not going to say how much fun and informative it was reading it.

Glad to see that its a fairly newly dated thread as most concerning classic bikes are 2008 to 2010 and nobody reads anymore. Also interesting to see that it's posted on a Honda forum which incidentally is my favorite manufacturer. So what am i doing with a Kwacker? Reading my blog wurnman.blogspot.com may give some answers. Apologies for the shitty English grammar and style as im not one known for his writing prowess and English not my first language.

Anywhoo, im getting some really tasty information here which i will surely use for my Project ventures in due time. Been a blast doing something like this project although im not as good as Ronski when it comes to taking engines apart.

If you read the blog you'll see that my bike was in pretty horrible state when i started. I even had to buy the last part, a right rearset from an Australian guy named Andrew (on the ZX Forums) who lived in Indonesia and worked in Bangladesh who asked his New Zealand friend who lives now in Australia to sell me one that my mate from South Africa (where im from) to buy it for me and bring it over when he comes back here after living in Ausy for 20yrs. Very global indeed.

Lataz all and thx for the awesome read...