how to polish a turd (a 750 mod thread)...

[Nibor]

so i've de-registered my duke, knowing it needs a bit of decent work, and the time it will take to do this whilst we have our 3rd kid, i cant justify keeping it registered just to sit in the garage. After some late nights snooping about the forums, and weighing up some options, ive decided to do what many other illogical, moneywasting 750 owners do - polish their turd!

yes i know, buy a 900 engine at half the cost, blah blah. i dont want that. I like my turd.

so the list of mods i want/hope to do so far:

- FBF high comp pistons
- 620/800 heads to compliment
- new OEM clutch basket
- barnett clutch plate kit
- machine stock flywheel
- machine new OEM primary gear (worth doing at all? ive a new one with the new basket)
- rebuild mikuni carbs
- either pods or open airbox
- LIFO/lightweight battery, maybe relocate
- new tank, probably CA cycleworks
- new fuel/air lines etc, all rubber is old old old.
- new fork seals, respring and fresh oil whilst there.
- SS rims.... massive weight savings (ok so they were a bargain and i prefer the thinner three spoke look)

will add to this as I go, all i can think of at the moment.
this is to compliment what little mods ive got so far:

- ohlins rear shock.
- 900 adjustable front forks
- cycleworks exactfit coils
- K&N air filter
- remus low mount pipes.

im very limited by funds, so will be doing as much work myself/with friends, only limited by my poor spannering ability.

pics to follow throughout winter.

[Nibor]

questions i have so far:

regarding the heads, from what ive read 800 heads will be slightly better than the 620? but apparently 620 are cheaper and easier to come by?
is there a particular year range i need to look out for with the heads?
do i need complete heads, or are my 750 components transferable, and its just different porting in the heads that im after?

the heads/pistons are going to be one of the more expensive components to the build, so im still up in the air about it.

[Speeddog]

What year turd are you polishing?

I've been very happy with the Factory Pro parts for the Mikunis.
I've not compared directly with Dynojet stuff...... but.....
The first FP kit I did was on my own M750, fuel mileage went up 25%, and it ran better *everywhere*.
Same results I've gotten on many carb sets since then with FP stuff.

620 heads have the same size valves you've got now, so not a lot better.
695 or 800 heads will have the bigger valves and better cams.

'06 and earlier are 8mm valve stems, at least here in the states.
That restricts it to 800 heads.
Not a huge deal, but they seem to hold up a bit better than the 7mm stuff.

You'll want the heads complete with valves, cams and cam end covers.
Your 750 cams and valves are shyte and don't fit straight up, and the end cover is different.
Valve covers and rockers and rocker shafts will swap over.

I've had limited exposure to Barnett wet-clutch plates.
That first exposure was completely unsatisfying, but that was an APTC pack in an S2R800.
So, YMMV on an early wet clutch.

[brad black]

your's is a 97 motor, and the 98 and later reversed the o-ring recess location.  so you'll need later cylinders as well.

i'd suggest you'd buy this: http://www.ebay.com.au/itm/Ducati-800SS-Engine-Motor-GUARANTEED-/140786212065?pt=Motorcycles_Parts_Accessories&hash=item20c7831ce1&_uhb=1

or this: http://www.ebay.com.au/itm/DUCATI-900-MOTOR-FUEL-INJECTED-98-TO-2004-SS-OR-MONSTER-ETC-GOOD-CONDITION-AS-IS-/120968251322?pt=AU_Motorcycle_Parts_Accessories&hash=item1c2a4507ba&_uhb=1

but i see you're committed to doing it the hard way.

[Nibor]

so if i get heads off something else, i'll need cylinders to match.

what is better with 620 heads, if the valves are the same?
other option which has been pointed out is keep the 750 heads, and fit bigger inlet valves with a bit of machining.

worth replacing the cylinder studs whilst doing any of this? currently perving on the Nichols website...

[Speeddog]

620 cams are a more modern design, and higher lift, compared to the 750.
Ports may be better, but I've not compared side by side.

Given the amount of work involved, IMO it's worth the extra cost of the 695/800 heads.
You're not on a tight time schedule, so availability isn't such an issue, yes?

I'm not aware of the small motors having stud issues.
California Cycleworks has their own studs at ~1/3 the price of the Nichols units.

[koko64]

Edit: So the whole shebang top end for early 750s then.
I 'spose it all depends on what parts you can scrounge up cheap. A friendly machinist might make 900 inlet valves fit and you might find cheap 900V cams.

Brad, your 750 motor still for sale?

[brad black]

Brad, your 750 motor still for sale?

yes.

the pre 98 heads have the o-rings in the heads.  so you could get the later heads machined to take o-rings.  get pete smith at epicycle to do them.

don't use 620 heads.  they have a short duration inlet cam which works well in a 620, and apparantly quite good in  big bore 620/750 (ask nick).  otherwise they're much as you have now.

800 heads have a bigger chamber to take the 900 valves, so you'll need very high comp 750 pistons to make them high comp.

i found a 696 motor on ebay germany for 650 euro that they'll send to au for 45 euro.   put 696 heads and cylinders on it.

[koko64]

Your 750 motor is very well developed, maybe Nibor should sell his motor and buy that ?

[Nibor]

i did notice that for sale comment in one of brad's writeups  but then i'd miss out on all the fun haha.

im guessing the machining just the heads for o-rings would be comparable if not cheaper compared with sourcing cylinders too. FBF make 11:1 and 12:1 piston kits for the 750, so the 12:1 would suit with the 800 chamber, still achieving a decent ratio yeah?

is it any 800 head? so S2R 800, 800SS, 800M all the same engine, on different setups?

[dansamp]

PM sent

[Nibor]

The following alternator cover gasket for a pantah engine should fit I think. Anyone can confirm?
I know the CA Cycleworks alternator cover gasket doesn't fit, that's 98 spec onwards (with external clutch slave cylinder)
http://ducati-gowanloch.com/catalog/ducati-pantah-alternator-gasket-p-2387.html

[koko64]

Others will confirm, but surely that's the correct gasket? Dealer have any left?

Polish away Nibor

[brad black]

yes, pre 97 is same as pantah.

[Nibor]

Thanks Brad!