Rebuilding the beast! 99 748s

Pictures inside

15 years is a lot of crud on the pipes, but they cleaned up well.
Strong coffee and a few beers goes a long way.

Youtube has some great stuff about wet sanding your way higher through the grit ## to mirror perfection. I don't have a rear hugger yet but after this amount of work I will get one.

Pictures inside V2

When I got back from overseas- the track season was over. I ordered some pretty busted up fairings off ebay at a low price of maybe 200. Cant remember.

Patched all the holes scrapes and low spots with bondo and lots of fiberglass. Then shot with some flat black via rattle can.

I also shot the carbon fiber exhaust with some clear coat after lightly using ultra fine sand paper on it. They carbon pops again like new! No weird bubbles.

Before I had this bike I had never even changed the oil in our cars. Now I'm doing a full top end rebuild on the cheap!

Might try to find a blown engine for doner parts in the future. 90-100 bucks a piece for an opening rocker arm sucks! There are some old engines on craigslist for a couple hundred. If I can get just three worthy rockers out of the scrap it would be worth it.

Valves eeeeek?

Got the vertical head cleaned up pretty well.
Then started to tackle the valves. My first time with Ducati valves... well really any valves.

Man the closers are tight. My loaded value was never more than one or two thousandths more than the unloaded. Both for exhaust and intake. Why would someone set it up that tight?? None of them made the "click". I tried multiple methods of depressing the closer to no avail. (screwdriver, homemade depressor tool (office chair lever modded) and allen key. I felt one move a little but nothing that would increase the gap by much...

Also made sure the cam was in the correct position. (pictures in LT Snyders manual)

Looks like ill need to sand/swap out some shims to open back up the gap to atleast .004 vs .002.

When the valve seats and valve lips wear, the opening clearances get tighter as the valve pushes deeper into the head. You don't get this problem very much with Ducati's however because the valve never really slams shut like pop valve engines. However, on older motors with a lot of wear, you may see things like this start to happen. Another common issue with unusual clearances comes from carbon build up on the inside of the valve seating area. This of course generally only happens on exhaust valves, but it does the opposite thing, causes MORE clearance on the openers and generally tighter clearance on the closers. Another cause of odd clearances is the half rings failing on the closer shims. These tend to crack and fall apart on the older motors. Ducati has made them out of harder materials over the years to prevent this, but to this day, half ring failures are top of the list on causing unusual clearance issues. Make sure you do pull the valves out to clean the backside and install them back into the same places you got them from.

I've physically been in motors where people had pulled the retaining springs out and run WAY TIGHT clearances as a consequence. It's very rare to see this, but with desmoquattro's, anything is a possibility. I've seen engines with .002 clearance all the way around as well... so clearly not valve wear.

Since you're re-building, it may behoove you to research MBP collets and shims. The kit isn't too expensive and it will give you loads of shims to properly re-shim the engine AND the MBP collets won't fail like the Ducati OEM one's will. This will allow your motor to probably never need another valve check! I'd also verify the rockers are in good shape. The 748's are notorious for chewing up chrome on the rockers due to the higher revving nature. Loose clearances are one of the culprits of that very problem.

I'd also yank the piston's, clean them up and the cylinders up. It's probably smart to replace the rings as well since you're in there. Doing the bottom end is a whole other can of worms that you probably don't want to get into right now. I'd just pull and push on the rod with no piston attached to see if there is ANY play. It should be tight enough to have zero play in and out. You should be able to twist the rod slightly, but it should feel firm. Also the rod WILL slide back and forward on the crank, so don't be concerned about that. These engines do have pretty robust bottom ends if treated well.

Engine in the frame, heads on the bench, ode to the days of desmoquattro engine repair!

Enjoy the service, it's a fun bike to work on and well worth the time and effort to do it yourself.

howd I do it?

Madryan said:

What did you use to polish up your pipes... mine are a bit "tea stained" with age now as well.. 14 years, but not looking quite as aged as yours there...

Click to expand...

@Madryan, I used a few different methods, sorta tried to see which worked and which didn't.

The chemicals were used at first to get the thick dark colors off, like the header below. (wd40 and carb cleaner)

Then I switched to a few drops of dish detergent d(dawn) and hot water. Hot because its cold outside. I just tossed pieces of sand paper into the bucket and then wetsanded going up in grit. Starting with 220, 400, 600, 800, 1000, 1500 finally 2000.
If you make to large of a jump in grit to quickly, it only means your sanding with longer. The gradual really helps out early on. (I learned this). If you have an orbital sander it would rock to use it on the lower grits!
After the 2k I used a buffing compound on a bench grinder I got off craigslist. Swapped out a harsh stone for the buffer and snagged a rue from ace. That really made the mirror shine POP! That was sorta seeing where I could go with it. Not sure If I will do the entire system that way or not. But still neat to see what is possible.

video tutorial

Flaking Rocker Arms 748!!! yuck!

They sorta look worse in the pictures than how they feel. None snag my fingernail in any way.

I have changed the oil maybe three times since I have had the bike and not seen flakes. The oil filter screen and drain plug was always pretty clean too. My guess is they were this way for awhile. Only one half ring was broken, still in the correct position though.
Hopefully the horizontal head will look better.

Had one closer shim stick onto the valve. Shit. wiggled could not get it to drop down... Flip through Snyders manual sure enough I remember reading about it. Use a socket extension, and towel around the valve, few taps and its free. Man that book was worth every penny.

Plan is to finish heads first then tackle the pistons.

Question: Do I use the closer shim tool to also measure the opening shim? It seems like that would be the right way to do it.

Tail Tidy and Fresh Clutch

I used Anti-hero's tail tidy DIY: (What's up Dennis!)

How to: Make your own license plate bracket - Ducati 1299 Forum

That light I put under there is super bright, and it makes the real wheel look larger. I like it. It might not work in this position after I get a carbon hugger. No worries, it's easy to move.

Picked up some high temp caliper paint. Red and black on the stock pressure plate and springs. Prep is everything! The previous owner gave me a box of parts which included stock rear turn signals, some used brake pads but plenty of life left. (maybe race pads?) and a box with DP performance written on it? Whats that?

Previous owner told me it was old clutch plates in the box... I opened it up and found a brand spanking new clutch kit- Major win. The rattle was excessive and the old plates were mushrooming back. (not that it sounded bad in any way rattle rattle rattle!) Kit cost $250 new. Man what a WIN! Bling on.

pictures!

Valves were easy to clean using this method.


I didn't touch the seat area though, You can still see a little bit of carbon on them. This picture was before I lapped them. Once I lapped with a fine compound it really took care of the last spots. I also used the wet test which actually is stellar if you put a lot of work into them.

Pistons had massive amounts of buildup. This actually took the most time of everything to clean... But yep that's the reflection of my tool bench on the piston. Not Bad.