and so it begins ... 800 engine build !!

[dansamp]

just starting to gather pieces to upgrade my M750ie

this will be a slow process since money is tight right now but,

just won this off ebay  :  

http://www.ebay.com/itm/331144577621?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

going to get some 800 heads and have them ported and polished,
not sure if I will go with bigger valves , any recommendations ?
I am thinking of going with  900 SSie cams since ST2 cams are now extinct

planning on sending the crank to Fox for lightening and balancing etc

does anybody know any good engine builders in Austin Texas ??

any suggestions please let me know

 

[koko64]

Check out Brad's bikeboy.org site, topic Ducati Cam Specs. Don't think the older cams are going to fit the newer heads and vice versa. Speeddog and Brad know what fits what. 800 heads fit 750 barrels. They have big enough valves. I toyed with the idea of running high comp pistons in a 750 with 800 heads. That would give you better valve sizes, cams and ports from the advice I was given from those guys. The 800 heads with bigger combustion chamber requires hi comp pistons according to Brad.
If your 750 motor was ok, I would have fitted hi comp pistons and 800 heads. Much less work. You would swap the 750 cam pulleys onto the 800 heads. Again this is all second hand as I didn't get to do it, but those guys will know.

Great project BTW.

[dansamp]

yeah i could but this way I get the 6 speed trans

not sure if I will go with the 800 crank
maybe keep the 750 crank

brad's site says that 800 heads use the 900 carbie cams
and ST2 cams fit into a 900 head
so anyway its all just beginning anyway 

[dufukincati]

Try AMS in Dallas if you want someone to build it for you.

[koko64]

Fair enough, the 6 speed is better.
Love builds like this.

[thorn14]

I've seen this as far as cams go.

http://www.speedzilla.com/forums/ducati-supersport/22935-race-cams-800ss.html#post226187

[kopfjäger]

Get a used 1000ds engine and save some aggravation.

[dansamp]

Get a used 1000ds engine and save some aggravation.

yeah but I like the idea of a small engine

like so:
http://www.ducati.ms/forums/57-supersport/106431-750-ss-motor-build-started.html   

[kopfjäger]

yeah but I like the idea of a small engine

like so:
http://www.ducati.ms/forums/57-supersport/106431-750-ss-motor-build-started.html   

Then start with a 900. 

[Speeddog]

800 crank requires (short) 800 pistons, that's how they make 'em work with the longer 800 stroke.

[brad black]

ideas:

1/ start with a 900 is a great idea.  use a 748 crank to make it 853 if you must.  you just need some longer rods.  it's a stronger bottom end.

2/ instead of 800 heads use 796 heads and cylinders.  900 crank to raise the pistons 1mm and reshape the crowns as required to fit the chamber and give you more comp.  bigger valves straight away.  1100evo cams for some duration.

3/ 1100 motor.  no replacement for displacement.

the later cams (not ds) have two bearings, not three.  so you need a spacer at both sides to make the bearing edges the same.  if you have them side by side it's obvious.  all 2v, non ds cams will fit.

[dansamp]

now I am more confused than ever  


thanks for chiming in Brad 

ideas:

1/ start with a 900 is a great idea.  use a 748 crank to make it 853 if you must.  you just need some longer rods.  it's a stronger bottom end.


2/ instead of 800 heads use 796 heads and cylinders.  900 crank to raise the pistons 1mm and reshape the crowns as required to fit the chamber and give you more comp.  bigger valves straight away.  1100evo cams for some duration.

3/ 1100 motor.  no replacement for displacement.

the later cams (not ds) have two bearings, not three.  so you need a spacer at both sides to make the bearing edges the same.  if you have them side by side it's obvious.  all 2v, non ds cams will fit.

too many options

at this rate maybe I should just get a new bike ??


Speeddog,

you mention short 800 pistons,
on the FBF website they list Hi Comp pistons for 750/800 and they are the same piston ??

not sure what to make of all this

my thought was a small/nimble high revving engine (smaller than 900) and at least 90+ rwhp
with 888 tank and bodywork fitted onto my 2002 M750ie

[brad black]

there's a guy in adelaide that's revving a 696 based race thing to 12 from memory.

high revving 2v is a bad idea for a road bike imo.  big, heavy valves beating the shit out of the valve train.  you need to fit an 848 evo motor into it.  then you could rev it.  and have no midrange, just like an 848 streetfigther.

800 pistons are 2.25mm shorter in the comp height compared to 750, due to the 4.5mm stroke difference.

how much money are we spending?  90 is quite a it from an 800 or less cc motor.

[brad black]

what you need is a mv brutale 750 with an spr motor.

136hp at 13,000 rpm.  yeah baby!

it'd be nuckin' futs.

[dansamp]

there's a guy in adelaide that's revving a 696 based race thing to 12 from memory.

high revving 2v is a bad idea for a road bike imo.  big, heavy valves beating the shit out of the valve train.  you need to fit an 848 evo motor into it.  then you could rev it.  and have no midrange, just like an 848 streetfigther.

800 pistons are 2.25mm shorter in the comp height compared to 750, due to the 4.5mm stroke difference.

how much money are we spending?  90 is quite a it from an 800 or less cc motor.

I was thinking of going with a bigger bore as well, not sure that would make much of a difference
I have found hi comp pistons for 750/800 but no big bore kits 

as far as high revving I was meaning 10-11k

a previous bike 900 SS I had was built to 944 with MBP heads and ST2 cams and split FCR's it would still be pulling past 10k

wish I still had that bike 

as far as money not sure since I am going to do it bit by bit 
probably not more than 3000-3500
anymore and i might as well invest in a different bike

you mentioned a 900 block with 748 crank would be stronger, but does that mean that a 800 block is weak ??

people race those right ??