Maintaining the fleet | Page 2 | GTAMotorcycle.com

Maintaining the fleet

Brian P

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Haha, we get the same minuscule private-message storage as anyone else. I cleared some space!
 

mxs

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With the wheelbase shortening, you will need wheelie control "sensor" of some kind ... :)
 

GreyGhost

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With the wheelbase shortening, you will need wheelie control "sensor" of some kind ... :)
Haha, like 40 years of riding motorcycles? IIRC he only went out a couple inches to change the weight distribution.
 

Brian P

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2 December: With a bit of help (needed, due to the awkward nature of this job), the engine is in the frame again. Engine mounts are torqued according to the procedure in the shop manual. Started connecting electrical components.

3 December: Primed the oil pump again with the engine sitting in its proper position and determined that the O-ring at the oil cooler is leaking. Installed the clutch. Filled the engine oil to its proper level to check for potential leaks at the oil pan gasket and drain plug. Re-routed the hoses that involve the stock oil cooler and my auxiliary radiator (these bikes are notorious for running hot) to eliminate an air pocket that made the cooling system hard to fill last time. Secured wiring harness around the engine.

7 December: Throttle bodies are back in; putting those in is one of the more ignorant assembly chores, and I had to do part of the job twice because there is a small hose to the cooling system that connects to the thermostat housing which is inaccessible once the throttle bodies are on, and of course I forgot about it until they were in. I can't do anything underneath the engine yet, because the oil pan gasket is weeping a little, and I'm waiting for the new gasket (which should arrive tomorrow). Changing it requires dropping the oil pan, which means I can't put the exhaust on yet, which means I can't put the radiator on yet.
 
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Brian P

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Yaaayy, we have a runner! I spent a couple hours confirming that the engine will, in fact, not run if the crankshaft position sensor is unplugged. :) Plugging it back in required getting the throttle bodies off the engine to get access to the hidden connector that I missed on my initial check-over, and that of course required removing the fuel tank and airbox and putting all that back together again ... while my battery was on the charger because I discharged it with all the cranking attempts. But now, it starts and runs, sounds good, has oil pressure, charging voltage is good, cold start fast idle works (and that hasn't worked properly in years). The throttle bodies need to be synchronised at some point but that can wait until after break-in.
 

matt365

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Yaaayy, we have a runner! I spent a couple hours confirming that the engine will, in fact, not run if the crankshaft position sensor is unplugged. :) Plugging it back in required getting the throttle bodies off the engine to get access to the hidden connector that I missed on my initial check-over, and that of course required removing the fuel tank and airbox and putting all that back together again ... while my battery was on the charger because I discharged it with all the cranking attempts. But now, it starts and runs, sounds good, has oil pressure, charging voltage is good, cold start fast idle works (and that hasn't worked properly in years). The throttle bodies need to be synchronised at some point but that can wait until after break-in.
And it no longer smokes like a two stroke?

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Brian P

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Not that I can tell! The exhaust smells a lot less, which is a hopeful sign. I'm not going to run the engine again until we have a warm enough day to go out and beat on it to try to make sure the piston rings are seated this time. In the meantime, it's up on stands again, and the next job is to take the wheels off and have a look at the brakes. I also want to pull the shock out of my race bike ... a decision on what to do with that shock hasn't been made yet.
 
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Brian P

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Dunno. The chap who changed the oil and recharged it this past summer after it lost all damping wants to take another look at it to see if there's a way to beef up the shim stack. It looks like it will be guesswork either way.

When I have the shock out (probably tomorrow) I'm going to make some measurements of the shock linkage in an attempt to figure out the motion ratio between the rear wheel and the shock. I have a spring in there which is off the scale by current 600cc standards and we think it's blowing through the high-speed valving on the piston.
 

matt365

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Dunno. The chap who changed the oil and recharged it this past summer after it lost all damping wants to take another look at it to see if there's a way to beef up the shim stack. It looks like it will be guesswork either way.

When I have the shock out (probably tomorrow) I'm going to make some measurements of the shock linkage in an attempt to figure out the motion ratio between the rear wheel and the shock. I have a spring in there which is off the scale by current 600cc standards and we think it's blowing through the high-speed valving on the piston.
So it loses all damping when the shock heats up?

Is the shock an fzr400 aftermarket unit, or is it off another bike?

Guess it has to be period correct to be Vrra legal.

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Brian P

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Fox Twin Clicker, originally meant for a fizzer. Fox stopped supporting these about 15 years ago. It's not really a matter of the shock heating up ... the piston seal inside the shock is apparently worn out and is letting fluid bypass the damping control circuits, which is part of the problem. The other part of the problem is that with modern slicks on 17" wheels, it has grip that this shock was never originally designed to handle. I've had to go up and up in spring rate, and it's at the point where the original high-speed damping circuits (the shim stack) isn't capable of controlling it. I have a Penske on my other (street) Fizzer, one of the options if the Fox is beyond saving is to buy another one.
 

matt365

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Fox Twin Clicker, originally meant for a fizzer. Fox stopped supporting these about 15 years ago. It's not really a matter of the shock heating up ... the piston seal inside the shock is apparently worn out and is letting fluid bypass the damping control circuits, which is part of the problem. The other part of the problem is that with modern slicks on 17" wheels, it has grip that this shock was never originally designed to handle. I've had to go up and up in spring rate, and it's at the point where the original high-speed damping circuits (the shim stack) isn't capable of controlling it. I have a Penske on my other (street) Fizzer, one of the options if the Fox is beyond saving is to buy another one.
You can't just swap the penske off the street fzr and put it on the racebike? Got to be better than the fox that has no damping.

Nobody can sourse the parts to rebuild the piston in the fox 2c?



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Brian P

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Nobody can sourse the parts to rebuild the piston in the fox 2c?
Aftermarket copies of the internal parts appear to be available but not at the snap of a finger, and the parts involved aren't rocket science and can be copied but it takes time. When the shock needed work over this past summer I needed it back in a week, not enough time to deal with it properly. Now there's a bit more time available :) I needed to get the ZX10R off the hoist so that I could use it for the fizzer, which is now likely to tie up that spot in the shop for a month or two. The ZX still has a to-do list, but the rest of it can be done with the bike on paddock stands.
 

Brian P

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On the Fizzer ... 1.5" of rear wheel vertical travel in the normal range of movement translates to 9/16" shock motion ... 2.67:1 motion ratio. Newer sport bikes are in the 2:1 range (my ZX10R is close to that). Explains why it wants such high spring rates since the spring rate needed will be related to the motion ratio squared. My 13 kg/mm or 730 lb/in spring translates to a 7.35 kg/mm or 102 lb/in wheel rate, and that's not much.
 

Brian P

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Yesterday's ZX10R progress: I found more worn-out stuff. Worn-out brake pads were expected. The other one was not.

The test-run revealed an oil leak behind the left engine cover (starter motor reduction gear and clutch live underneath that cover). On the original engine build I did not separate this cover from the starter motor because I didn't have to, it can all come off as one assembly. The oil leak meant that it had to come apart. On re-assembly ... I'm not happy with how the gear on the starter motor shaft meshes with the idler gear. It seems that the hole where the idler gear's shaft resides is wallowed out. I tried taking it apart and cleaning up all of the parts involved including the O-rings ... no joy, it's not really any better. The gears themselves look OK.

I think it's time for NRC covers.

Getting to the two bolts that secure the starter motor to the engine is a bear. Factory service manual procedure is to remove the throttle bodies, drain the cooling system, remove the coolant hose and fitting that connect to the cylinder block roughly above where those two bolts live. The time-saver was to unplug only the two connectors on the left side of the throttle bodies so that they could be tipped up and held up with a bungee cord, leave the coolant fitting in place, then use an 8mm socket, a 1/4"-drive universal joint, a 1/4"-drive ratchet extension to get past that coolant fitting, a 3/8 to 1/4 adapter and two more 3/8" ratchet extensions to reach all the way down there and have enough room to swing the ratchet. And a small flashlight to shine light on the problem area.
 

boyoboy

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Fox Twin Clicker, originally meant for a fizzer. Fox stopped supporting these about 15 years ago. It's not really a matter of the shock heating up ... the piston seal inside the shock is apparently worn out and is letting fluid bypass the damping control circuits, which is part of the problem. The other part of the problem is that with modern slicks on 17" wheels, it has grip that this shock was never originally designed to handle. I've had to go up and up in spring rate, and it's at the point where the original high-speed damping circuits (the shim stack) isn't capable of controlling it. I have a Penske on my other (street) Fizzer, one of the options if the Fox is beyond saving is to buy another one.
hey brian, I really enjoy your wrenching posts. Always clear and easy to understand. Anyhow, a long while ago someone directed me to Z1 cycle for servicing old fox shocks. They are one of the few places that offered bladder replacement and more on the old fox shocks. Not sure if the same tech is still available there, but it might be worth a check/option for you.
 
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Brian P

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NRC covers are on, and they are really nice pieces - local company that does a really good job. This fixed the starter reduction gear ... you can no longer wiggle the shaft around and there is much less backlash between the idler gear and the starter motor.

The remaining jobs, including installing new tires, are all little fiddly things that I can spread out over the rest of the winter.
 

Brian P

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I did something about another thing that might as well be addressed with the bodywork all off the bike. The first-generation ZX10R was the lightest of them all ... and one of the things that was made too light, was the bodywork, particularly the tail section. It's flimsy. Years ago, the tabs that hold the taillight broke (happens to all of them). I reinforced the tabs by building up superglue and baking soda and then used a stripe of silicone to pretty much permanently hold the taillight in place regardless of tabs. Then the next-weakest points broke ... one of the tabs on the little cover behind the passenger seat broke, and the tail section itself split beside the center mounting point on each side (underneath the passenger seat). This is one of those things that happens to all of them, and there's no point replacing with new parts, because they'll be the same.

I glued the tab back on:
- Clean surfaces with acetone
- Apply a stripe of ABS solvent cement to the broken surfaces
- Hold them together in position until the solvent evaporates enough for it to stay put
- Apply another layer of ABS solvent cement to build up the tab a little bit to give it a fighting chance of staying together.
- Let it sit to cure for a few hours.

I reinforced the split sections near that center mounting point:
- As above, to mend the splits back together
- Wipe the inside surface of the bodywork with acetone
- Apply a piece of fiberglass and then a couple layers of ABS solvent cement on top of it in the affected area beside the tab
- Apply another piece of fiberglass underneath the tab itself extending out over the other piece of fiberglass
- Trim excess out of holes and edges.

The messiness gets covered up by other parts of the bike and isn't visible. Even the splits aren't visible until you take the seat off ... only the resulting floppiness of the panel.

The later models all have better-designed bodywork that is secured in place better and doesn't do this. Every generation of sport bikes gets the "how light can we make it" treatment. This was the "Oops ... that was too light" generation.
 

Brian P

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The ZX10R is done and test-ridden. I just got back now. Seems to run very nicely.

Collectively, the only thing I'm still waiting for is the revalved shock for my race bike. And I sent my leathers out to be cleaned and I don't have them back yet.
 

Brian P

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Got the shock back for the race bike, and installed it just now. It seems to have damping now. Won't know any better until late May.

And with that, the four bikes that were the subject of this thread are, as near as I can tell, done and ready to go.
 

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