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Thread: Summer running - 2000 Ducati ST2

  1. #166
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    24th September 2004 - 06:46
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    '76 CB550 Super Sport
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    I don't get why ypu need that brass extenion at all. Is the cable too short? I mean my '76 550 has it's original cables connected directly to the battery with no issues at all in all these years. In those days large crumped cables were soldered at the ends if they weren't enclosed so there is contact with all the strands..
    "Every time you set your ass on a bike, you're playing a game of Russian Roulette between yourself and your own stupidity."

  2. #167
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    28th January 2015 - 16:17
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    Good point. I guess Ducati weren't keen on cables crossing the battery top surface, with electrolyte ports straight underneath that wiring. Also, the manual explicitly states that cables sharing a terminal post should be set at 90 degrees, which makes sense - this guarantees that spade lugs on the same post are sitting on their flats, not tightened up against each others barrels. So with packaging constraints the only smart way to do it was to take the cables out to the flank of the battery and rotate the attachment plane by 90 degrees via an adaptor.

    Using a steel adaptor was questionable though and that's why I've gone to brass. The other reason to keep something similar to the original setup was that the main loom was set for that position. I could force it to the battery terminals directly but that'd be putting a strain onto the wiring that I wouldn't be happy with.

  3. #168
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    28th January 2015 - 16:17
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    Inlet manifolds

    Manifold O-rings having arrived, I opened the bike up tonight and got the inlet manifolds onto the bench so I could have a proper look at things.

    Getting at the manifolds was a bit fiddly. Drain tank, prop tank up, remove airbox (pull vertical cylinder's airbox to throttle body rubber out through the airbox first), unscrew injectors from throttle bodies, unplug TPS, and bingo, straight to the inlet manifolds. Which is where it got a bit difficult...

    I haven't pictured this but whoever designed the manifolds didn't leave enough room to get a normal ring spanner onto the nuts. I ended up taking an angle grinder to one of mine, thinning the web of the spanner down, in order to make it fit. The clearance between manifold wall and stud is so tight that the flanged nut itself can foul on it. The nominal torque setting on this fastener is 23.5 Nm; I have no idea how I'm going to set this torque on the rebuild. Even 1/4" drive sockets won't fit in here since the manifold overshadows the axis of the stud enough to block a drive. Perhaps some open end crow's foot spanners are necessary, but maybe it's just better to set the nut back by feel with the same combination spanner I took it off with. It's got a self-lock metal washer built into it so it won't come off.

    The stock O-rings are fine. There's maybe the tiniest hint of set - maybe. They still look like they've got a nominally round cross section and they're definitely proud of their grooves. If there was a vacuum leak, it wasn't from these.

    The inlet manifolds themselves though... yeah it's not good. I am pretty sure that the vertical cylinder's manifold (pictured) has a crack, visible over around 1/8th of the circumference and probably spread wider. It also looks like the stock manifold has thick rubber but thin aluminium, particularly in the area where it's bonded together. There's also what looks like permanent shrinkage of the rubber away from the manifold. It's not hard to believe that it could be leaking, maybe quite badly, once it's up to temperature.

    I'm not sure if they arrive like this or if someone's had a go, but it also seems that something like a Dremel with a flap wheel has been used in an attempt at porting. There's lots of clearly hand-cut marks on the inside of the manifolds. It looks like already thin aluminium was taken down to the point where the rubber started to show through, ie bits of this manifold's casting are now paper-thin and it's only the blobby rough-cast outer surface left holding it all together. Patches of rubber on the inside appear to be crumbling, and also whatever cut the aluminium has had a go or two at the rubber as well. Anyway, if someone's had a look inside some brand-new manifolds, I'd appreciate feedback on these comments.

    Ah well. Shopping time. In a way it is a result; if this is the problem then it's a pretty straightforward fix.
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  4. #169
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    24th September 2004 - 06:46
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    Looks like after the rubber was bonded to the ali manafold there was a bit of protrusion on the inside edge and someone during assembly used a dremel or similar to smooth it out but went a but too far. I've had to grind a spanner as well for some bikes I've owned for a similar purpose. The rubber itself looks perished as well as crumbly at outer edge and they can split with use/age. Could olso have be damaged by someone else on removal/fitment as well.
    "Every time you set your ass on a bike, you're playing a game of Russian Roulette between yourself and your own stupidity."

  5. #170
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    3rd March 2008 - 11:55
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    Quote Originally Posted by OddDuck View Post
    The nominal torque setting on this fastener is 23.5 Nm; I have no idea how I'm going to set this torque on the rebuild.
    If you can swing a spanner, measure it's length and hang a spring balance off the end of it, crude but reasonably effective return to first principles.
    Riding cheap crappy old bikes badly since 1987

    Tagorama maps: Transalpers map first 100 tags..................Map of tags 101-200......................Latest map, tag # 201-->

  6. #171
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    28th January 2015 - 16:17
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    Thanks guys. New manifolds on order. Neels, I'll see about purchasing a spring balance, that's a good trick.

  7. #172
    Join Date
    8th July 2018 - 07:46
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    Ducati ST2 2003
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    whakatane
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    Manifold torque

    You could do up an exact same nut on a bolt with a torque wrench and get a feel for it with a ring spanner, then do your ones up the same, the torque is not going to be super critical on those anyway, I normally only use as torque wrench on head studs and other critical bolts like cam shaft caps, main bearing and connecting rod nuts etc.

    Might be of help and simpler, when you are torquing in an awaward situation, if you stop and restart you need 40% more torque to start the nut moving again which is why you torque to a setting and to check, you mark the nut with felt.pen, loosen and retorque.

    In this situation where you are just grabbing little parts of the turn each time I think you will find any method of actually measuring torque will be impossible.

    While you are in there check your head studs tightness by hand, always seems to be one or two loose ones on every bike I check.

  8. #173
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    24th September 2004 - 06:46
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    Quote Originally Posted by OddDuck View Post
    Thanks guys. New manifolds on order. Neels, I'll see about purchasing a spring balance, that's a good trick.
    If it was me I would've cut the vulcanised tubes off then fit wire reinforced rubber tubing(radiator hosing or similar) to attach the manifold and airbox and suitable hose clamps.
    "Every time you set your ass on a bike, you're playing a game of Russian Roulette between yourself and your own stupidity."

  9. #174
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    28th January 2015 - 16:17
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    I had a look at your idea Bonez but it isn't a straight or simply thing to do on these. There's a shift between centers on the rubber, from where the throttle bodies sit to where the aluminium manifold begins. Maybe it could be done but honestly I've got my plate full... at this stage I'm happy to wait on new spares. I've already paid for them anyway.

    Neels, yes, I should check head nuts. Should be done at every service interval according to the manual.

  10. #175
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    28th January 2015 - 16:17
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    I finally decided to pressure test the manifolds to check for leakage. This involved turning up a bung with a tyre valve, and drilling two bolt holes into a spare bit of flat plate. The test itself was to pump up to approx 15 psi (1 atm) and submerge in the kitchen sink, then look for air bubbles, similar to finding a pinpoint puncture on a tyre tube. It's not quite a pure test, the proper thing would be to test under vacuum, but I didn't have something that pulled air instead of pushed it so this would have to serve.

    There weren't any bubbles, on either manifold. It looks like the rubber's alright after all.

    While doing this I finally noticed something that I should have seen much earlier: the O-ring flanges aren't flat. They're bowed, quite badly... a quick bench test with a light nip-up on the bolts and use of a feeler gauge showed a gap in center of 0.2 mm. Further work (not photographed) of placing the manifold back onto the cylinder head and shining a torch inside clearly showed the curved gap between the two. The manifolds will actually rock sideways by a few degrees on the mounting interface. It is definitely not a flat to flat contact. This is only obvious once the O-rings have been removed from the manifolds, though.

    The O-ring groove is (by verniers) roughly 2.0mm deep. The old O-rings measured at 2.54mm across the face-to-face part of the circumference, and around 2.7mm across the groove wall area, so it does look like they've been setting with time. I think that if the manifolds end up being pulled to one side or the other during or after installation, it'd be possible to have all of the gap on one side of the interface, doubling it, so it'd be approx 0.4 to 0.5mm. A quick look at the thermal expansion coefficient of EPDM rubber gave a figure of approximately 0.1 parts per thousand, m / mK, which is a positive expansion. This can exert a lot of force. So I think it's possible that the parts of the O-ring nearest the bolts push hard enough to bow the manifold flanges and thus reduce the contact pressure on the O-ring in the middle, perhaps to the point where it opens up.

    As to why this happened... either the manifolds were cast this way (possible but unlikely) or the metal has been very slowly distorting over time via cold flow (aka creep). This last is very likely to my mind since the O-rings will assert constant force on the inside of the manifold. It looks like the manifolds are made from diecast aluminium alloy, probably one of the Alum-Zinc alloys, and this stuff is known to have issues with continual flow under strain even at ambient temperature. The manifolds have been loaded up for nearly twenty years straight.

    The fix is simple: put a flat plate onto the bench, put some wet-n-dry onto the plate, slowly and carefully flatten the manifold face again. I'll need to take around 0.4mm off, almost all of that at the outer tips of the flange.
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  11. #176
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    28th January 2015 - 16:17
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    Right, inlet manifolds flattened and refitted, with new O-rings. The alloy proved to be quite soft and it didn't take much time on the wet'n'dry to sort out the flange's curve.

    I took the bike for a brief test ride last night and this looks like it's sorted out most of the problem. Experience has shown that this bike responds well to regular use (keeping injector nozzles cleaned out?) so at this stage the plan is to just ride it for a couple of weeks and see how this goes.
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  12. #177
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    8th July 2018 - 07:46
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    Ducati ST2 2003
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    whakatane
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    Fuel economy

    Well done enjoy it for a couple of weeks and let us know how it goes.

    On another note, I have been tracking my fuel economy and it is working out at 19 km/l ridden hard and 21km/l when ridden softly or longer trips, that means u can get 430 kms out of a 22.7l tank.

    I have not been brave enough to run it that far but the other day at 360kms I still had over 4 l in the tank when I refilled it.

    The rated consumption is 16.2 km/l

    Interested in what you and others are getting.

    Cheers
    Noel

  13. #178
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    24th September 2004 - 06:46
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    That's damn good going Noel. How long have you had the bike?
    "Every time you set your ass on a bike, you're playing a game of Russian Roulette between yourself and your own stupidity."

  14. #179
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    8th July 2018 - 07:46
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    Ducati ST2 2003
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    whakatane
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    St2

    Hi thanks, I have had it 2 years now, been right through it and added a rebuilt Ohlins to the rear. Good move.
    Recently put MBP valve closer shim retainers in it,3000 km so far, going to check clearance shortly and will let you guys know if they are worth the $125 US$

  15. #180
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    24th September 2004 - 06:46
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    Nice. Looking fwd to your feedback.
    "Every time you set your ass on a bike, you're playing a game of Russian Roulette between yourself and your own stupidity."

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