Transmission issues on 2008 FE550

Taffy · Oct 9, 2018

fe600racer said:
Click to neutral while rolling or when stopped reach down with left hand and give a sharp controlled pull to neutral from first or controlled push from second. Your foot is not sensitive enough to do this. You get used to this as you do with your foot just before you stop. Try it.

that'll be a pre-2002 then! by the way the selector claw is not mentioned enough in all this.

if you have a pre-2003 you have the double whammy of the old drum AND the narrow steel selector claw. these burr over on the ends and the sliding plate jams up.

it is easily modified, just skim the wide parts off on the side of the grinding wheel.

taffy

canadius · Oct 9, 2018

Taffy said:
its the clutch drum problem in the 2002s and that leads to warped plates. in the 2003-2008s it is just warped steels.

the only other thing that comes up is that the clutch pack height (all 15 plates) can vary enormously. if it is very tall, you need a pill on the end of the clutch pushrod. but the opposite can happen as the pack goes down.

remember that the 2003-2008s can have 1.4mm steels in it and there were 1.8mm frictions and 2.0mm frictions.

so there can be a difference of a new pack with 4 x 1.4 steels in it and 7 x 2.0mm frictions compared to all 1mm steels and all 1.8mm frictions of 3mm.

yup 3mm. and the throw of the clutch is only what? 1.5mm? maybe 2mm tops.

you can tell by looking at how far out the piston is within the slave body.

cheers

Taffy

Hi Taff,

Great answer. I think the pic shows the difference in wall thickness.

Alternatively, my question is this: are the walls that hold that o-ring in place equal thickness on a new cylinder? Intuitively, I'd say yes, and the scoring I'm seeing suggests there's been excess wear.

As to your sitting proud or too low due to clutch thickness issue, I'll look into that if a new piston doesn't solve it.

But if you can please confirm the thickness of the walls issue, that would be very helpful.

cheers,

c

Taffy · Oct 9, 2018

the piston will be tipping over repetitiely and wearing things out. so which dimension do you want measuring? i have new pistons here but not bodies.

Taffy

canadius · Oct 9, 2018

Taffy said:
the piston will be tipping over repetitiely and wearing things out. so which dimension do you want measuring? i have new pistons here but not bodies.

Taffy

Thanks Taff,

How about the overall width of the piston / O-ring "sandwich" - from the outer edge of the innermost "wall" to the outer edge of the outermost "wall". And if possible, the thickness of each of the two walls of the

That will speak to your point about the overall "stack" dimension.

I'll add a pic in a few minutes.

Thanks again!

c

EDIT: pic added. 3 mea

Taffy · Oct 10, 2018

the thin wall is 0.4mm and the thick wall on the nose side is 0.85mm. the overall width is 3.34mm.

in all honesty, it is the O ring that goes, it is after all; just an o ring. it isn't a proper piston seal. anyway, steel is never going to wear when rubbing against the aluminium of the clutch body.

there is a bush meant to go into the entrance to the gearbox, we never discuss it here but that would help straighten up the piston. but nobody has that bush. weird innit!!!!

the further that 'nose can go in the 'truer the thing will probably run. your problem is that the liquid (the mineral oil) comes in from one corner and rather like blowing up an air bed, it lifts that corner first.....seriously!

so that is why the piston really does want to be forwards a little.

cheers

Taffy

canadius · Oct 10, 2018

Hi Taff!

Thanks a bunch for taking those measurements. I'm baffled, because they are the reverse of what I expected; I expected if anything, mine, as used, to be worn and thus smaller.

At least they confirm that the walls were indeed different thicknesses.

FWIW, my dimensions are

thin = .48mm
thick = .89mm
overall = 3.46mm

But no matter, I am agreeing with your offset motion thing. Along the rear HALF of the perimeter of the cylinder/piston contact surface (call it from 12 o'clock to 6 o'clock) it is completely untouched. Whereas on the other HALF, (7 o'clock to 11 o'clock) there is some mild scoring. Not perceptible to my nail or a fine O-ring pick - but visible nonetheless. So, yes, for whatever reason, that piston has seen some minor offset movement relative to it's rotation center.

Also, and perhaps related to this, the thin edge seems a bit sharp - so I could see it causing / contributing to that scoring if the piston is tilted as you're suggesting. The O-ring itself looks happy and round (both in shape and in cross-section.

I'm going to mull your overall "stack" dimension thing. Maybe open up and measure the plates/steels. I'd like to know more about this "pill". Perhaps extending my overall stack is the reverse of what I need, but I feel like I'm slowly zeroing in the root cause, and it looks like there's a fundamental dimensional issue going on along that overall system.

If the "pill" is an item you sell, please pm me and we talk offline about the feasibility of ordering one.

cheers,

c

bushmechanic · Oct 16, 2018

A few of us have made bronze bushings to help.hold the piston square. In fact the "problem" with this area is that the pushrod that the piston acts on often has its end ground incorrectly ie not square. Pop it in a lathe and machine a concave depression in the end. Then the piston isn't forced off axis by the rod.

canadius · Mar 28, 2019

Hi,

Life issues have gotten in the way and have finally found the time to tackle the transmission. Plus the Taffy "pill" took forever to arrive (not his fault, we had a crippling postal worker strike) so am back at this in earnest.

Am still having issues with the clutch not fully disengaging from the engine. I'm noticing no leaks, but continuous presence of bubbles up in the master coming from the piston port. I've bled lots of mineral oil through the system, and no leaks or bubbles from the slave. So am going to look at a few basics first;

1) Master piston - put in a new piston kit. As I've done with other bikes, I drained the fluid, removed the master and slave cylinders, blew out the system with air through the clutch line (bottom up), and replaced the master and reassembled the system.

2) Master cylinder - I've never honed on past rebuilds. Do folks recommend honing? Size of ball or other hone kit recommended?

3) Master cylinder cover - stripped screw extraction via drilling means I've munged up the nice anodized "Husaberg" branded master cylinder cover. OEM is part number 590.02.033.000 - but I think that's just a plain white metal cover. Other than the Hammerhead designs version - here: https://www.amazon.com/Husaberg-Magura-Clutch-Master-Cylinder/dp/B00DT8D2WS - does anyone know where else to source this?

Thanks,

c

Taffy · Mar 29, 2019

I have a piston in stock and a cap too! to bleed it, you must drive the fluid through from the bottom to the top with a syringe. everyone has tried the old ways and they don't work. your problem is likely to be the O ring on the piston and nothing more.

just a little tip; undo the screws for the slave one complete turn and the cover should push out when you pull the lever. this proves that the piston is functioning (or not) and that the problem is still there or infact in the clutch area.

Taffy

canadius · Mar 29, 2019

Thanks.

I’ve got a fairly new slave piston in there.

Before leaving for work I loosened the 3 slave bolts and pulled the clutch. I felt it shift out, wouldn’t say I clearly saw much of an outward deflection of the body from only a threads worth of loosening, but it shifted out enough to start a small bit of fluid leak.

Will see why it won’t bottom bleed this weekend.

fe600racer · Apr 2, 2019

The hard to find nuetral is normal as is some resistance to pulling bike backwards. The upside is you don't get nuetral by mistake. If you can plan ahead get neutral while still moving....if not use your hand to pull gear lever.....if you over shoot into second push sharply down to nuetral. The hand works since you can control it better than your foot. Make sure you have all the parts in the clutch and the basket has not clutch plate indents...and away you go.

Taffy · Apr 2, 2019

fe600racer said:
Make sure you have all the parts in the clutch and the basket has not clutch plate indents...and away you go.

that won't be long.....

Taffy

Transmission issues on 2008 FE550

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