Need help - sag, master cylinder, header leak | GTAMotorcycle.com

Need help - sag, master cylinder, header leak

TwistedKestrel

TwistedKestrel

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Trying to combine this all into one topic is probably a fool's errand but if I make three posts two of them will get ignored, plus I kinda don't want to spam the forum. Long story short, I finally have some time for the project in the garage, and I want to pick GTAM's brain(s) so I don't have to think as much. This is a 96 or 97 ZX-11, I actually can't remember which lol

1. I need to adjust the sag on the rear suspension. I think the suspension guy (who has since closed up shop) said it was excessive some years ago, but neither of us wanted to touch it because changing the preload is an enormous pain in the ***. I know that it's 1 15/16" right now, but how do I figure out what it should be? I don't remember the spring rate, it will take some serious excavation to figure it out but it was picked for me specifically (and I haven't gained any weight)

2. I suspect master cylinder is bad, or at least the rebuild kit in it crap. Will evaluate it more thoroughly, but if I were to replace it what would be good OEM (or otherwise cheap) replacements? The calipers are 6 pots of a K1 GSXR 1000 (I think, uses that one super common brake pad for 6 pot calipers)

3. The fit on the exhaust is pretty terrible. I expected better from Hindle, but the time for taking that up with them was probably ten years ago. It leaks at one or more of the flanges the header connects to. The original installation instructions said to use high-temp RTV on the joints and that was not done, will that actually work or is that a waste of time?
 
1.The rule of thumb for sag is 20 to 30% of total travel is a good starting point. Others may have a better answer for a motorbike.
2.No idea, can't help you.
3.I have had no luck with high temp goo to seal a header leak without complete disassembly. It just blows out. Maybe it will fix your problem, but I ended up removing the header, installing a new gasket and using a thin film of goo on both sides of the gasket. It isn't clear from your description, are you leaking between the header and head or at an intermediate joint?
 
GreyGhost said:
1.The rule of thumb for sag is 20 to 30% of total travel is a good starting point. Others may have a better answer for a motorbike.
2.No idea, can't help you.
3.I have had no luck with high temp goo to seal a header leak without complete disassembly. It just blows out. Maybe it will fix your problem, but I ended up removing the header, installing a new gasket and using a thin film of goo on both sides of the gasket. It isn't clear from your description, are you leaking between the header and head or at an intermediate joint?
Click to expand...

Is there a simple way to figure out travel?

I'm talking about an intermediate joint. FWIW I'm also talking about disassembling it to apply the goo, not to try and apply it in situ. The connection between the header and the flanges (short parts that are bolted to the head) has no gasket and is attached by springs
 
1) I set the sag at 25mm for the street, 30-35mm for the track... if the spring rate is correct.
2)6 pot Tokico calipers? Notorious for being hard to bleed. Are you sure the problem is in the master? What size is the master?
I have those calipers on my GS. I was not happy with the stock 16mm master and switched to a 19x20 radial master and haven't looked back.
3) Yes high temp silicone will work. The copper stuff is better than the red stuff. Use new gaskets or orings.
 
TwistedKestrel said:
Is there a simple way to figure out travel?

I'm talking about an intermediate joint. FWIW I'm also talking about disassembling it to apply the goo, not to try and apply it in situ. The connection between the header and the flanges (short parts that are bolted to the head) has no gasket and is attached by springs
Click to expand...

With a couple people it should be possible to raise the rear of the bike until the suspension is fully extended and then measure between two vertical points (say the rear axle and grab handle), then put a fat person (or two) far back on the seat (you made need to push down some too) and repeat the measurement to get compressed height. Subtract and bingo bango you're done. Otherwise just go with Bitzz suggestions and then total travel doesn't matter. You are probably way over the recommended sag in any case at almost 2" on a sport bike.

I know what you are talking about with the headers now. I might try to lap them so they fit better, but it may not be possible depending on what other parts are in the way (unless you unbolt the stubs, but that may just make more problems than it solves). Maybe bitzz is on to something and there is supposed to be a gasket in there in addition to goo. Worth checking a parts diagram (if you can find one).
 
I'm pretty sure it's the master, there is a long history of troubleshooting behind it before the bike got parked. The master is stock but I can't remember the size
 
bitzz said:
1) I set the sag at 25mm for the street, 30-35mm for the track... if the spring rate is correct.
2)6 pot Tokico calipers? Notorious for being hard to bleed. Are you sure the problem is in the master? What size is the master?
I have those calipers on my GS. I was not happy with the stock 16mm master and switched to a 19x20 radial master and haven't looked back.
3) Yes high temp silicone will work. The copper stuff is better than the red stuff. Use new gaskets or orings.
Click to expand...

I think you meant to say 30-35 for the street and 25mm for the track. not the other way around.
 
If you find setting sag a pain I would seek out a suspension guy. What are you looking for? smooth softer compliant suspension, or a firmer sport/sport touring set, or all out sport riding? Each will be set different.

What is your sag front and rear - you only give one number, for the front Im guessing? 30-35, or even 35-40 would work. Look for balance fr and rr (within 5mm of each other - with equal sag fr and rr or with a maximum of 5mm more sag at the fr than the rear. Do NOT have more sag at the rear than the front.

there are many you tube videos on the net. Look for a video from a reputable source such as motorcyclist magazine etc..
 
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boyoboy said:
If you find setting sag a pain I would seek out a suspension guy..
Click to expand...

I meant the process of actually adjusting the preload, because of the dumb way the shock sits inside the bike. The shock may even have to come off (yet another thing I don't remember, but at that point of disassembly removing the shock is pretty much only one extra step). The sag I gave was only for the rear, if matching it front and rear is a real thing then that makes it easy for me
 
GreyGhost said:
1.The rule of thumb for sag is 20 to 30% of total travel is a good starting point. Others may have a better answer for a motorbike.
2.No idea, can't help you.
3.I have had no luck with high temp goo to seal a header leak without complete disassembly. It just blows out. Maybe it will fix your problem, but I ended up removing the header, installing a new gasket and using a thin film of goo on both sides of the gasket. It isn't clear from your description, are you leaking between the header and head or at an intermediate joint?
Click to expand...

^this, new gaskets b4 you call hindle a crappy fit. lol
 
TwistedKestrel said:
I meant the process of actually adjusting the preload, because of the dumb way the shock sits inside the bike. The shock may even have to come off (yet another thing I don't remember, but at that point of disassembly removing the shock is pretty much only one extra step). The sag I gave was only for the rear, if matching it front and rear is a real thing then that makes it easy for me
Click to expand...

watch a motorcyclist magazine you tube vid on setting sag beginning to end. - several times, until it all makes sense. Your owners manual should have something on actually adjusting the sag.

I highly doubt the shock needs to come out for this.
 
You usually don't find a lot of pot holes and frost heaves at the race track (Let's try to ignore Shannonville and Cayuga for the moment), they're, as a rule, fairly smooth, therefore allowing for a softer, more compliant spring. The softer spring gives the dampers a break, and allows them to work better.
 
boyoboy said:
Your owners manual should have something on actually adjusting the sag.
Click to expand...

True story - it tells you to get the dealer to do it. They were space constrained and made some bad decisions (e.g. the ZX-11C has a remote reservoir for the shock, the ZX-11D eliminated it although my bike has a Racetech reservoir added)

Also I really hate mining Youtube videos for information, didn't somebody write this down somewhere
 
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bitzz said:
You usually don't find a lot of pot holes and frost heaves at the race track (Let's try to ignore Shannonville and Cayuga for the moment), they're, as a rule, fairly smooth, therefore allowing for a softer, more compliant spring. The softer spring gives the dampers a break, and allows them to work better.
Click to expand...

your backwards... less sag will make a bike quicker steering at the track.
 
TwistedKestrel said:
Is there a simple way to figure out travel?

I'm talking about an intermediate joint. FWIW I'm also talking about disassembling it to apply the goo, not to try and apply it in situ. The connection between the header and the flanges (short parts that are bolted to the head) has no gasket and is attached by springs
Click to expand...

use the racetech method....for sag
 
GreyGhost said:
With a couple people it should be possible to raise the rear of the bike until the suspension is fully extended and then measure between two vertical points (say the rear axle and grab handle), then put a fat person (or two) far back on the seat (you made need to push down some too) and repeat the measurement to get compressed height. Subtract and bingo bango you're done. Otherwise just go with Bitzz suggestions and then total travel doesn't matter. You are probably way over the recommended sag in any case at almost 2" on a sport bike.

I know what you are talking about with the headers now. I might try to lap them so they fit better, but it may not be possible depending on what other parts are in the way (unless you unbolt the stubs, but that may just make more problems than it solves). Maybe bitzz is on to something and there is supposed to be a gasket in there in addition to goo. Worth checking a parts diagram (if you can find one).
Click to expand...

why two fat people? sag should be set with the weight of the person(s) most often on the bike. Im gone. Way too much bad advice here (on setting sag), and I do not know why you wouldn't educate yourself by watching a 20 minute vid.
 
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I haven't got a clue what my sag is but I do know my spring rates. Not once this season was I asked what my sag was set at.
 
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