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!
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 (http://www.amazon.com/KD-Tools-850-Diameter-Compressor/dp/tech-data/B0002STSMG)
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 (http://www.ebay.com/itm/Air-Cooled-VW-Engine-Ring-Compressor-88-94mm-/310337783079?pt=Motors_Automotive_Tools&hash=item484192c527&vxp=mtr#ht_1091wt_856) 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!
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.
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.
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.
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.
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...
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.
Quote from: bond0087 on April 25, 2012, 07:31:25 AM
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.
996 isn't carby
Quote from: Dan on April 25, 2012, 01:56:23 PM
996 isn't carby
EFI can't ping from the wrong octane?
Quote from: ducpainter on April 25, 2012, 02:04:47 PM
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.
Quote from: Dan on April 25, 2012, 02:11:33 PM
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.
I stuff a bit of rag in the case around the rods when putting in the pin clip, incase it drops inside engine.
Quote from: monsta on April 25, 2012, 03:19:19 PM
I stuff a bit of rag in the case around the rods when putting in the pin clip, incase it drops inside engine.
a good idea whether in the chassis or not. [thumbsup]
None of the Ducs have a knock sensor. but your 4 valve is water cooled, has a different combustion chamber design, etc. My friend's BMW 1100RS pings on anything less than 91 with 10.7:1 compression, and will even ping on that if oil temp gets a little on the hot side.
Quote from: howie on April 25, 2012, 03:34:19 PM
None of the Ducs have a knock sensor. but your 4 valve is water cooled, has a different combustion chamber design, etc. My friend's BMW 1100RS pings on anything less than 91 with 10.7:1 compression, and will even ping on that if oil temp gets a little on the hot side.
I understand that chamber design and water cooling affect things.
Chamber design has a much larger overall effect I think.
Quote from: ducpainter on April 25, 2012, 02:19:43 PM
I don't think any Duc has a knock sensor...not even with the Siemans ecu.
What I was getting at was the motor was designed and set up with that compression, fueling and timing. It's pretty standard the 900 motors with HC pistons need timing and fuel work to run right
Quote from: Dan on April 25, 2012, 03:48:33 PM
What I was getting at was the motor was designed and set up with that compression, fueling and timing. It's pretty standard the 900 motors with HC pistons need timing and fuel work to run right
I'm not disagreeing.
He probably will need to do something...
He's not running a 900 though. He has a 750 so the parameters are somewhat different.
Just like with my water cooled 4 valve. ;D
Quote from: ducpainter on April 25, 2012, 04:09:33 PM
I'm not disagreeing.
He probably will need to do something...
He's not running a 900 though. He has a 750 so the parameters are somewhat different.
Just like with my water cooled 4 valve. ;D
Just like ;D
Thanks for all of the thoughts... I'll be stuffing a rag in there for sure, because spending an hour trying to find a dropped pin clip would just be classic me :) Thanks for the tip!
The info on what does/doesn't ping is appreciated, and I'll add another data point to the "will it ping" discussion when I get done... hopefully not when trying to figure out how to fix my ruined engine! I've got no problem switching to the highest octane I can get my hands on, though. Premium and 45mpg still beats the hell out of my car at 20mpg on regular, so I'll still be happy with the cost.
my stuff on hc 750 and ignition
http://www.bikeboy.org/brads750m.html (http://www.bikeboy.org/brads750m.html)
http://www.bikeboy.org/ducati2vignition.html (http://www.bikeboy.org/ducati2vignition.html)
same crap chamber as a 900, just smaller bore. should ping. altho mine is surprisingly resistant to pinging, but it does have 900 cams. it has ferracci pistons, allegedly 12:1. never checked it. i remember years ago a guy emailed me who had bcm fit high comps to his 750. it pinged, so they told him to fit 900 cams. not sure if he did or not.
i always replace base gaskets, but they're cheap and i have to guarantee the work. i think i left my std ones in, squish was ok at that. use threebond 1215 or equiv.
a 4v motor should see 12.5:1 without pinging, altho 996 like a bit less timing at that. but a 996 has about 3 - 4 more degrees at wot than a 916 even, so it's a bit of a apples to oranges thing unless you know the actual eprom and ignition mapping. and the advance is digital, not a single step thing. that's why the 2v ping. 12:1 makes a 900 go nuts.
i'd fit an ignitech unit, easier than pullig the alt cover and moving then regapping the pick ups.
Thanks for the response, Brad. I actually read those two articles (and most of your other 2V related ones) already, they are very informative. Your 750 article made me want high compression pistons, but maybe that was the wrong conclusion to draw from the article.
I makes sense that the Ignitech system would probably be the better way to go, but I've got way more time than money right now (being a grad student and all), so I think I'll try rotating and regapping the pickups first. Plus my left side engine cover leaks, so I'm hoping to clean up the mating surface, use some fresh sealant, and hope that I kill two birds with one stone there. The single step ignition advance that they do with the 2V doesn't seem like the greatest idea in the world; I'm not surprised that it causes trouble.
Do you know what engine speeds are most prone to detonation? I noticed that your ignition timing in general is less advanced at higher engine speeds, is that because those higher speeds are more likely to detonate? Or is the low engine speed right around where the timing jumps to full advance the real problem area?
Just wanted to say thanks again to everyone that responded! [beer]
I put my new pistons in this weekend, and it all went reasonably well. The job wasn't without difficulties, but when it was all said and done, I pressed the starter button and it roared to life first try!
I did the job in the frame (thanks ducpainter), and I would say that is certainly the right way to go. The frame hardly ever got in the way, and removing the engine would have been a pain. I definitely dropped the wrist pin retaining ring down the crank case onto the rags that monsta suggested, so thanks again for that, saved me a lot of trouble.
I went ahead and retarded the timing all the way and filled her up with 93 octane. I didn't hear any pinging, but it's hard to say for sure, because I only rode it about a mile, and not under much load (I finished at 2am, and my bike is not exactly quiet).
I'll post some more details and useful pictures / information for others thinking of doing this job once I get a few miles on it and I can get a better impression of the difference before/after.