Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > 748 to 853 conversion??? Please help...

[RiggsyB]

Right... Reading some stuff on Sigma Performances website yesterday (and remembering back to an article in one mag a couple of years back about their 853R), has got me thinking about saivng up for an 853 conversion for my 748SP...

BUT... I've got several questions... First and foremost, is cost... Bearing in mind, my mate's got his own 955SP engine apart at the moment (he's an engineer for a Ferrari specialist, and is pretty good with Italian engines), I'm keen to save on as much labour as possible, and do the work myself (with my mates help)... OK, I know stuff like mapping would then have to be done by a specialist, but the actual engine assembly can be done at home easily enough I reckon... So, how much would the parts (and the setting up after engine reinstalled) cost? I understand it's just a case of new barrels and pistons... Is that true? Or what else is needed? And is it perhaps worth having the heads ported whilst the engine is apart, or not worth the hassle for any extra dosh?

Next main question is that is the 853 modification reversible? Ie. if I want to revert the back to 748 spec for sale, and keep the 853 pistons and barrels, is that easily done without the engine being irreversibly modified?

Next is is it worth it? Or would I be better off swapping my (VERY good condition) 1997 748SP for a similar 916SP or 996SPS for £1500 to £2000 on top of trade in for my 748? Or will I find the 853 a much sweeter bike (I kinda like the revvy nature of my 748, but the fact it still has a lot more grunt than a Jap 600)...

And Finally, whilst I realise horsepower isn't everything, I read that Sigma Performance's 853R (standard engine apart from barrels, pistons and minor porting work as I understand it) makes 120bhp at the back tyre... Which puts it about 3bhp off a 996SPS, but with (in my opinion) a much sweeter power curve (I like a few revs)... So what kind of power would I expect from my 748SP??? 110 to 112bhp at the back tyre maybe?

Come on here... I need advice as to what to work towards... I love the bike, don't realy wanna sell it, but would love to make it quicker without losing its character...

[Jasper]

The engine work is reversable and easy to do.Just a matter of barrels and pistons.My Ferracci kit was £750 all in including gaskets.Not sure if teh head work is worth doing,but i have been well chuffed with mine and been perfectly reliable.Fuel set up is only a mtter of putting an FIM Ultimap chip in!You can get it fine tuned later.Timing etc is the same as the 748.Mine went from 87bhp to 105bhp.So basicall a 20hp jump.50mm termis are worth investing in.

[keith_mann1959]

I have been thinking about this conversion for my 748 when the warranty runs out. Niel spalding of Sigma explained to me that because of the extra oomph you usually don't need to rev so high for any given situation. Therefore the engine will get an easier life as an 853.
Make sure the bigger pistons are the same weight as the 748 ones.
The bigger question is, do you tell your insurance company?

[DJ Tera]

Originally posted by keith_mann1959

The bigger question is, do you tell your insurance company?

Only if they can tell its a 853 without stripping the engine

[ali]

Had a chat about this with Rich @ Louigi Moto last weekend (obviously not for my bike!). His take was that the 853 conversion gave the bike the perfect balance between grunt and revs, and was very reliable. Seems like an ideal upgrade, especially if it's as easy as Jasper says.

Cheers,

Ali

[Jon]

I think Nelly at Cornerspeed may be able to help with the 853 kit. I'm sur he bought a few sets in last year.

[flyingbanana]

Look at it this way. If you can afford a ducati you may aswell get it perfect. An 853 is just that. Had all sorts done to mine good and bad. A few pointers. Sigma are ok but would rather do the work then sell you the parts. Ferrachi do a piston kit which jasper pointed out, good value if your doing all the fiddly bits yourself. Give Alan at AJ racing a bell on 0145 384 5544 he did my conversion and is a great bloke for work or just a chat. Definatly get a FIM unltimap chip they do an 853 version, I found that my engine just didn't get on with the Power commanders fine for minor mods or jap bikes but stick with FIMS for a ducati can't go wrong the fueling and idle is spot on plus you get an extra 500rpm. You will see benifits from a gas flow mine was a 115hp monster on a 54 mm full system and 65ft after the gas flow by HM RACING in kent it went up to 116hp and 68ft but the graph and the ride was bonkers major gain in the mid range and top end just make sure the bloke knows what he's doing with that flow bench ! and set the fueling throttle position sensors and all that lark properly. If you can get an sp or sps go for that as the cams come into their own with the bigger bore plus the sps has titty conrods so there's peace of mind even though the revs stay the same might as well dial the cams while your at it too. My sps standard was 105hp and 55ft after all the work, just the kit and head job it was the aformentioned 116 and 68ft. Lastly consider beefing up the battery ie binning the electrolyte one for a gel type, checking the sprag clutch assembly is in good order and the generator for that matter, once the engine compression goes up it puts a bit of strain on the starter parts I should know . Nelly at cornerspeed was doing some kits and had good results the only difference i've seen is piston weight mine were heavier so I had the crank balanced but sigma's are the same weight so you makes your choice .As for insurance I've still got a 748sps thank you very much





Chucked a torque graph in for good measure, 54mm system and pc2, the red line is after the gas flow, mmm

[Edited on 27-5-2004 by flyingbanana]

[DC]

Hello mate,

I had my 748 turned into a 853 at Sigma. All i can say is that the cinversion IS worth the money. It has turned my bike into a, how can i say. A REAL WORLD BIKE.

It goes like stink. Has much more grunt. Will hit 160 MPH no probs and still revs like a 748. It will even lift its head coming out of bends.
You end up covering road distance like a missile without even knowing you are doing it.

I had head work done as well as a Full monty service at Sigma. To be honest. I would say that its all the power I need from the engine.

I have the termi pipes as well as the FIM chip.

If you can afford it then go for it. I am more than happy with it.