'00 M750, knowledge of possible upgrades required.

[stevebussard]

Hey guys,
   Just got back from the Moto GP in indy, and I have a couple questions that someone more knowledgeable than myself may know the answers to.  I have a 2000 M750, and my rear cylinder keeps fouling plugs.  It has very weak spark, but with an new plug runs pretty well for about 200 miles, then starts missing.  I think it may be the coil.  I talked with my uncle (who is a motorcycle mechanic of 40 years, specializing in exotic and rare bikes), and he feels it's not the coil, but more likely the end of the wire that snaps onto the plug.  I'm supposed to pull the plug wire off the coil and test the resistance.  I don't know how to get it out though.  Do they screw in, like some of the older style wires did?
   Also, and this is where it may get fun, and I hope someone knows the answer...  Will a '99 900SS engine and tranny bolt up to the mounts for my engine?  My uncle has 2 of these motors, and he said he may be willing to trade one of them for my motor, to get me a little more power.  I'm very excited about this prospect, but don't want to be cutting and welding the frame to do it.
Thanks for the help guys!

[ducpainter]

Some Duc coil wires are epoxied in to the coils and won't come out easily.

The 99 SS motor will work, but your carbs will need jetting for a 900 instead of the 750.

[bdfinally]

Mine were tight, but came out after I tugged firmly on them. Chris @ Ca-Cycleworks has some nice red NGK wires

[The Mad King Pepe']

Once you're at it you might as well get a factory pro jet kit for the 900 engine from Chris and get rid of the airbox in favor of some pod filters, then you can even get Dyna Coils and  and  [moto] and  and  [moto]

[stevebussard]

Thanks for the info guys.  I checked the wire for continuity, and everything was good.  Cut the wire back about 1/2" on each end and re-installed.  It runs a little better, but still not the way it did when I bought it.  I'm pretty sure it needs a new coil.
   I'll probably wait until this winter to swap the engines out, that way I can ride the rest of the season, and I can repaint the entire bike while it's torn down.  I don't know if the engines he has already have the carbs mounted on them or not, but if they don't, I will certainly pick up a factory jet kit from cylce works.  I'm not sure if I want to go with the open pod filters or not.  If I do I will build a custom battery tray and coil bracket mount.  I'm not really big on cutting up the original parts.  They tend to be worth a lot of money in good condition  .

[The Mad King Pepe']

I'm not really big on cutting up the original parts.  They tend to be worth a lot of money in good condition  .

you don't need to, just un-bolt the airbox and take it out. put a couple of K&N pod filters on and re-jet the bike. then you can sell your immaculate airbox for $$

I'm not sure if I want to go with the open pod filters or not. If I do I will build a custom battery tray and coil bracket mount.

Instructions here: www.ducatisuite.com/jetkit.html

[stevebussard]

That's a great tutorial!  That's about what I had pictured doing for a battery box to begin with, and now, I wouldn't even have to guess on anything.  Thanks.   

[The Mad King Pepe']

I remember seeing pics of other people who have done the same thing, here's the thread on this forum with a few alternatives.

Personally I just followed the 'directions' on Ducati Suite and everything worked fine for me on both my monsters. I bought a sheet of 6065 aluminum from Aircraft Spruce (7075 works too) and all I used was a cutting wheel on my dremel and a drill for the holes.
Post pics when you're done! 

[suzyj]

Just for reference, don't use 6061-T6 or 7075-T6 for parts that need to be bent or formed, like bits in the battery box - the heat treating that these alloys are supplied with makes them quite brittle.

5xxx series (generally 5052) is the best stuff to use for bending.

[Langanobob]

...5xxx series (generally 5052) is the best stuff to use for bending.

I think 5052 is the standard material for hiway signs, old ones of which are readily available in scrapyards.

[Langanobob]

Thanks for the info guys.  I checked the wire for continuity, and everything was good...

Just to be thorough, you should check the wires with an ohm meter and actually measure the amount of resistance in each wire.  A continuity meter can show continuity even if the resistance is too high.  Not sure exactly what the resistance should be, but both wires should be fairly close to being the same.   Maybe Howie knows what the resistance should be, he seems to be even older than me, and knows everything.

[Howie]

Secondary resistance is 19.5K ohms+ 20% (coil and plug wire).  The resister at in the connector to the spark plug is 5K ohms.  Chances are good the spark plug wire is epoxied into the coil.  While you are at it, you might want to check primary coil resistance, 4.5K ohms + 15%. 

he seems to be even older than me, and knows everything.

64 today or  , not sure.

[Duck-Stew]

If the bike runs great for 200 or so miles w/a new plug, have you considered that maybe your problem ISN'T the ignition system?

Since the bike sits on only a side stand when not in use, the fuel in the Horizontal float bowl actually rests against the needle/seat in the Vertical carb and if that's not working properly it can drain into the cylinder and also if it's not working properly, your fuel flow into the vericaly cylinder would be greater than the horizontal meaning that your vertical plug would foul out sooner...



As far as ignition wires are concerned on carbureted bikes, they screw into the ignition coils and therefore unscrew (they're standard thread BTW) to remove.  Coils generally don't go bad, wires do though...  Try new wires, but look into your carbs as well.

[stevebussard]

Since the bike sits on only a side stand when not in use, the fuel in the Horizontal float bowl actually rests against the needle/seat in the Vertical carb and if that's not working properly it can drain into the cylinder and also if it's not working properly, your fuel flow into the vericaly cylinder would be greater than the horizontal meaning that your vertical plug would foul out sooner...

  This is all very true, and would typically be of certain concern to me, however I just had the carbs rebuilt and sycronized two weeks ago (3 days before leaving for Indy).  I had put new plugs in it, and it ran awsome until I got roughly half way down there (it started missing slightly).  By the time I got there it was missing terribly.  I picked up a new set of plugs, rear cylinder was completely fouled.  I checked the spark, and the front cylinder was nice and blue, the rear cylinder was a faint orange.  With new plugs, it ran pretty good most of the way home, and started to hiccup about 100 miles from home.
  I am fairly certain that it is either the coil or wire (couldn't get the wire out to test the resistance).  In order to eliminate all ignition problems, I just ordered two new coils, wires, and the wiring harness.  (I got a really good deal from a Ducati technician).  Short of replacing the ignitor box, that should cover all possible issues, and should leave me with a spare "good" coil (assuming the coil is in fact the issue).  I will update when I recieve them and get them istalled. 

[64duc]

, not sure.

  I'm surrounded by children.   66.5 and counting.