Questions on replacing pistons

[bond0087]

I recently picked up a pair of FBF high compression pistons for my 2000 M750, and I'm doing the prep work for installing them.  I have a few questions on the job that I'd appreciate some advice on.

1.  Does the gasket between the cylinder housing and the block have to be replaced?  In manuals (Haynes and Ducati), it mentions that the o-rings need to be replaced, but I haven't seen anything that says that the gaskets need to be replaced.  Do they? To those that have done this job, have you replaced them or not?

2.  When removing the engine, does anyone follow the Ducati manual's way of doing it, where you leave the shock/swingarm in place, back the swingarm axle out half way, loosen the frame mount bolt, install a special tool on one side, then back it out the rest of the way, install the special tool on the other side?  After reading that, I just thought why not just take the shock and swingarm off? When I looked at the Haynes manual, that's exactly what they did.  Just wondering how others have gone about it.

3.  How much, if any, does the ignition timing need to be retarded when switching to 11:1 pistons, ('00 M750, pod filters, cored exhaust, dynojet stage 2 jet kit) , assuming that I switch to premium?  Can I get away with just retarding the entire ignition curve by rotating the pickups back a few degrees?  I don't want to use an aftermarket ignition system if it is at all possible to avoid it.

4.  How have others supported the engine while removing it?  Do people generally bolt up an engine stand to the engine while it is still connected to the frame, then lift the frame off, or just use some wood and a jack to support the engine, lift the frame off, and then put the engine on a stand?

5.  What sort of piston ring compressor have others used for this job?  Will any old piston ring compressor (like the one I could rent from Autozone for free) work?

Thanks in advance for any info and advice!

[ducpainter]

1 There is no head gasket. There is a gasket between the cylinder and case that is reusable. If you are setting squish you may need different thickness gaskets.

2 Why pull the motor? That job can be accomplished in the frame.

3 At 11:1 you may get away with just higher octane.

4 see #2.

5 you need one that will slip over the rod after you're done like this one... http://www.amazon.com/KD-Tools-850-Diameter-Compressor/dp/tech-data/B0002STSMG

[bond0087]

Thanks for the input.

Wow, I had no idea that the job could be accomplished in the frame; that makes this job a lot less onerous.  Is it tough to work on the vertical cylinder while the engine is in the frame or not?  I just figured it would be impossible to get at everything with the engine in the frame, but I guess I didn't look too closely at it. 

I'm not 100% sure if I understand why that style of ring compressor is used, but I might.  I'll write what I inferred from your statement and the Ducati service manual, and you can tell me if I'm just being thick or if I get it.  So I take it that when reassembling the engine with the new piston, the procedure is as follows:
-Install the rings, check orientation, clearances, etc.
-Install the piston onto the connecting rod, put the wrist pin in, circlips to secure it.
-Put the piston ring compressor over the piston/rings
-Push the cylinder down on top of the piston until the rings are all in the cylinder
-Take the ring compressor off
-Push the cylinder all of the way down

Let me know if I'm being an idiot here.  This is a little confusing because I'm just used to seeing on cars where you push the cylinder with connecting rod attached through the top.  As far as the ring compressor itself, I found this which looks like it will work, and is pretty cheap, but I just wanted to make sure that I understood exactly how to reassemble the engine.

Thanks again!

[ducpainter]

It can be done. On an SS you have to remove the front motor mount bolt and let the motor pivot down.

On a bike the rods and piston assemblies are in the cases (block) and you install the cylinder over the piston.

On a car the block and cylinder are one assembly and you push the piston and rod into the block and attach the connecting rod to the crank.

That type of compressor will work.

[Ddan]

On my 900 with the timing fully retarded I still ping with 91 octane, 92 is OK.  The lump on the flywheel determines the range of timing so unless you change the size of the lump, aftermarket ignition won't get you beyond the existing advance/retard limits.

[bond0087]

Thanks again for the help, ducpainter! That makes a lot of sense, but I didn't quite connect the dots until your comment.

Dan, thanks for the comment.  Out of curiosity, are you running 11:1 or 12:1 pistons? 

Regarding the max range of adjustment with an aftermarket ignition, correct me if I'm wrong, but from reading Brad's article on the subject, it seems that the size of the lump on the flywheel just dictates the difference between low rpm base advance and the full advance at higher rpm. I would think that the max advance would be limited by the positions of the coils with respect to the lump on the flywheel, and the position of the lump on the flywheel relative to TDC, but I would think that an electronic circuit could always delay a coil trigger signal further.  In fact when I was researching this, I figured out how I could use a few 555 timers, resistors, and capacitors to retard the timing further without moving the coil.  I don't think I'm going to do that, because I'm not an electrical engineer, nor do I have any experience building circuits that are weatherproof, but it was an interesting distraction at the time.  I'm hoping that I can just retard the timing a bit, then use premium, but I was looking into this as a plan B.

[Ddan]

I'm using JE pistons, they spec 11.5 / 1.   Brad also talked about removing or adding to the lump to change it's position on the flywheel relative to the pick-ups.  It may be possible to make it happen electronically but I don't know of any product available that does it. 

[bond0087]

Cool, thanks for the info.  I wonder how much that extra little bit of compression (as compared to 11:1) affects the tendency to ping...

[Ddan]

I don't know how they calculate the CR, but I checked my squish and it's no where near tight so I'm probably on the lower end of the available compression.

[ducpainter]

Cool, thanks for the info.  I wonder how much that extra little bit of compression (as compared to 11:1) affects the tendency to ping...

My 996 doesn't ping on 87 and the CR is about 11:1.

[Ddan]

996 isn't carby

[ducpainter]

996 isn't carby

EFI can't ping from the wrong octane?

[Ddan]

EFI can't ping from the wrong octane?

I would think the computer would be set up from the factory to handle compression and timing.

[ducpainter]

I would think the computer would be set up from the factory to handle compression and timing.

I don't think any Duc has a knock sensor...not even with the Siemans ecu.

[monsta]

I stuff a bit of rag in the case around the rods when putting in the pin clip, incase it drops inside engine.