[Rpaint82]

So I came across an actual barn find. A rough Ducati 748 that needed to be brought back to life. So far I've done the following
Replace all fluids. Hydraulics, oil, and coolant
New spark plugs
Tons of wiring
I removed the throttle bodies and injectors and had them ultrasonic cleaned. When I did that I removed the TPS sensor also. Put on all new gas lines and quick disconnects.
Resealed and lined the inside of the gas tank
New fuel filter.
And of course a new battery.
I put it all back together and started it. It took awhile for it to turn over but when it did. I had to keep it at a minimum of 3000 rpm or it would die. Also sounded rough with a mild pop from the forward cylinder. I was hoping to have it run before valve adjustments and cam belts but I'm at a loss now what's wrong..very cheap compression gauge = 100 psi vertical cylinder and 110 front cylinder. But that's probably the first start in 5 years .

 

[ducvet]

When you removed the tps did you re-set it with software or eyeball it?

I personnaly would swap belts first because it would be a shame to do all that work and junk the motor to save $100

 

[Rpaint82]

No I just put it all back together the same way I removed it. I have the belts ready to install. I have been looking for software to use for that 748 and cannot find any solid answers. I ordered this, as I was (told) it works to set the TPS.

 

[belter]

someone sold you free stuff and an expensive cable, unfortunately. the guzzidiag / iawdiag is also free and a bit more user friendly i believe.

the tps reset on a 748 is manual, not a button press via software. BikeBoy.org - Ducati 4V Desmoquattro Non Linear TPS Baseline Adjustment (plus ST3)

 

[Rpaint82]

I figured it wasn't going to be that easy, press of a few buttons.. I put everything in its exact position, but i guess anytime its messed with maybe it needs re adjusted.

 

[ProphetPVD]

I figured it wasn't going to be that easy, press of a few buttons.. I put everything in its exact position, but i guess anytime its messed with maybe it needs re adjusted.

A good rule of thumb, at least one that I've always practiced, is that anytime you remove a sensor which measures rotational values, e.g., the TPS, it is essential to recalibrate to ensure that fueling is accurate.

 

[Rpaint82]

Right on. Thank you all for your help. We only have 1 Ducati dealer/ mechanic option here in KC so I relay heavy on you guys or pay top dollar for repairs.

 

[belter]

i had someone tell me the other day that ultrasonically cleaning injectors is a real issue. i think meaning putting them in a little bath and buzzing them. not sure if the place i use does that after they've run them in the flow / clean machine or not, but this fella was very adamant on the phone. allegedly people had rooted his injectors that way.

have you checked the fuel pressure? well worth doing at the return into the tank.

is assuming it ran ok before it was parked in the barn a valid thing to do? maybe it didn't.

if it has been sitting often the valve seats are a bit crappy, but they should clean up pretty quick.

 

[Rpaint82]

Yeah just a half bath is about all it is. With a very friendly cleaner. What is the best way to test fuel pressure? After seeing the inside of the gas tank when I found it. I did not try to start it. I did spray a little gas into the throttle bodies and it did start but just for a second. I didn't push it.

 

[ducvet]

So I would start with re-setting the tps as it is easy to get that wrong.
If after you set the tps and change those belts it does not work then you might re-visit the injectors as you have touched them. To be honest I see bikes all the time that have sat for many years. I seldom see injectors that have needed cleaning and the few we have cleaned were not noticeable on the dyno or gas tester. Not saying it hurts to clean things only that I have not personally seen great benefits/needs. I will also add it is cheap to have them professionally cleaned/rebuilt and flowed so why not?

 

[Rpaint82]

Absolutely I think I will continue on that path and will keep you all posted. Are these ebay chips worth installing (when everything else is in working order) are they plug and play? Or go power commander

 

[ducvet]

Look for a ultimap chip 097 IIRC . that may be the 853 chip though so double check.

 

[Rpaint82]

Another dilemma I need to figure out. With my compression gauge I'm at 90 psi vertical and 100 front. With 29 thousand miles. I can pay Ducati to "tune" belts,valves, etc my 748 .. if that's all it needs for about the same price I can get a used lower mile 996 motor and do a swap. I'm not looking for a bike to flip, I'm wanting to enjoy a bike I've always wanted. But on a reasonable budget. Last option sell the 748 for what I have in it and start over.

 

[ducvet]

Be careful with compression tests as a incorrect schrader valve in a gauge will give different numbers. A leakdown test will tell you more and better information like what needs help (rings,valves) .

Yes you can swap motors but I am rebuilding a hyper 1100 motor that spun a rod bearing. It was a replacement ebay motor because a timing belt job gone wrong , the crank is not reparable. So I just bought another crankshaft/ rod assembly off of ebay and yup one of the rods had spun. Buying a motor you are likely buying a motor from a salvage bike. that bike may have spent the last 1/2 hour running on its side with no oil which will.... wear out rod bearings.

Yes a 996 can be fun but go in knowing it will be luck of the draw for it to be better than what you have now. Some times you gotta take the cards you are dealt.

 

[Rpaint82]

Ducvet you are a man of wisdom. And very right !

 

[belter]

you should be able to grind the 1100 crank. grind undersize to suit toyota 4age bearings and sulphur nitride. you can get acl race series bearings for them, bearing surface is actually a touch wider than the originals. you need to machine a new locating notch in the rod to centre the bearings. heard of others using a suzuki swift shell too.

 

[Namor]

Belter....

 

[ducvet]

Oh the crank can be saved to be useful for sure, as always it comes down to costs. Which will cost less the used replacement crank that uses off the shelf parts (for the next rebuild) . or the process of modifying the existing crankshaft? If it was mine I might try the rebuild the crankshaft route but it still seems to be a safer route with a used GOOD crank. I even have a engine shop that plasma welds journals and then grinds to spec but I prefer to do that as a last resort and we are not there yet. Stage 1 is to find the simplest and most cost effective solution first if that fails then it is off to stage 2..... or jump right to stage 10....lol

 

[belter]

when i needed a crank for a 1000ds rebuild i couldn't find one - previously there seemed to be $300 cranks everywhere, when i needed one they were all $1000. the crank i had in that instance hadn't run the big ends, but it looked like the surface hardening was "delaminating" for want of a better term on the underside of the journal. looked really odd, and you could feel it and the bearings were really scratchy, not just worn looking like you'd expect after 75,000km. got me wondering if that's a cause of failure on the big ends. usually you'd expect an oil or bearing issue, not the crank surface coming apart..

 

[belter]

Belter....

?