Waste of money .....

[MonsterHPD]

So far, so good...
With reasonable valve clearances and reasonable cam timing, the engine turns without anything hitting. Hopefully I can test actual valve to piston clearances tomorrow. At least I can sleep well tonight :-)

[koko64]

  glad to hear.
Those cams also have a hell of a lot of duration.  Your 800 is stock capacity and compression?

[MonsterHPD]

Just tested the ST2 cams. Seems to be ample room for this:

ST2 Inlet CL 113 deg_01 by torbjörn bergström, on Flickr

Axial / radial clearance inlet / exhaust with inlet lobe centre 113°: 2.9/2.6 mm and 5.0/4.3 mm, respectively.

The motor is otherwise stock, but I´m thinking about removing the base gasket and machine the squish bands on the piston to get 1.0 mm squish height That will increase compression slightly.

I´ll try my hand at some porting next .... hopefully without destroying anything.   

[MonsterHPD]

Hello again.
Does anyone know the correct torque values for the head nuts?

[stopintime]

Hello again.
Does anyone know the correct torque values for the head nuts?

Three rounds: 15, 25 and finally 40 Nm

[MonsterHPD]

Three rounds: 15, 25 and finally 40 Nm

Thanks.
Same as for the 900, then.

[MonsterHPD]

I´ve done a bit more work on the M800, and the top end is now all dismantle.

Everything looks surprisingly good, except for some soot and  slight wear signs one might thnk the motor is new ....

2019-12-28 21.38.06 by torbjörn bergström, on Flickr

Pistons looking very good, top ringgap on one piston 0.28 mm, piston vlearance 0.02 to 0.04 mm both cylinders.
Cylinders are round and straight to withing ±0.01 mm. That is not too surpeising, as long as a Nikasil type cylinder has not been ruined by scratches and such, they tend to hold dimensions very well.

The ports are another issue, looking very rural to my inexperienced eye:

20200101_173907 by torbjörn bergström, on Flickr

Not too good a picture, it´s not quiteeasy to get good close-up photos with the cell phone camera. Anyway, the ports are very uneven, and the machining that has been made have no rounded-off interfaces with the as-cast surfaces. And in my eyes, the boss for the valve guide sits like a plug in the port ....
Also, the small radius / port floor where it turns down towards the bvalve is not a nice radius, it´s more like a shelf edge.

A couple of hours of Dremel work has got me this far:

2019-12-31 14.56.51 by torbjörn bergström, on Flickr

at least this pleases my eye a lot better. I´ve abandoned my initial plan to weld up the port floor etc in order to lift the port, since there is a thin-ish section vlose to the valva guide that I do not want to weld on. So I just try to make the whole port more even, and to creat room for some JB Weld at the "smalll radius in order to create a nice(r) raduis without reducing cross-section area.

At least I hope I´m improving things, but only next summer can really tell ...

With that, I´d like to wish everyone a Happy New Year  





  

[koko64]

 Happy New Year 

[pepeducat]

Hello, a few years ago, with a friend we made the assembly of camshaft of ST2 in cylinder heads of M800 which we then mounted on an engine of M750. 
It works perfectly, we just had to machine the cylinder base to go from 8.2 to 9.4 / 1 volumetric ratio. 
all mounted with Keihin FCR 39 carburetors and a few other little things, the monster released its 80 hp.

I put you below the link with the measurements of the holds for the camshafts


http://ducati-mostro-forum.fr/index.php?topic=1216.msg106015#msg106015

[MonsterHPD]

Hello, a few years ago, with a friend we made the assembly of camshaft of ST2 in cylinder heads of M800 which we then mounted on an engine of M750. 
It works perfectly, we just had to machine the cylinder base to go from 8.2 to 9.4 / 1 volumetric ratio. 
all mounted with Keihin FCR 39 carburetors and a few other little things, the monster released its 80 hp.

I put you below the link with the measurements of the holds for the camshafts


http://ducati-mostro-forum.fr/index.php?topic=1216.msg106015#msg106015

Gee, thanks a lot!. Will have to brush up my french as well :-)
I might be back wth some questions.

[MonsterHPD]

Evening (in Sweden, that is),

Now I have made the spacers for the cams as per drawings provided, and the width of the M800 cam is the sae as on the ST2 + spacers. Should work OK.

2020-01-08 19.04.00 by torbjörn bergström, on Flickr

Pepeducat,
I´ve looked thru the whole thread (with some problems understanding all). Anyway, there were some pictures of a motor after some problems due to very tight clearances between the valves on overlap (0.5 mm).

Since I have an ST2 motor with big valves built but not yet started, with approx. 0.6 mm between the valves on overlap, I´d be interested in more info on what happend, and why it happened. I´m worried about the 0.6 mm clearances ....  

[pepeducat]

No it was an assembly with NC7 camshafts which had been badly calibrated, so at the first shot of the starter everything hit with big damage.



With ST2 camshafts on an 800 it works very well.

To reassure you do a blank test of the squish valves / piston

[koko64]

Do you have some 900V carb cams? Be interesting to see the numbers with them.

[pepeducat]

This is the first thing I remove on a 900, the original camshafts which I replace with ST2 (HZ) or 900ie (8J), then I get rid of them because the cams are really not optimal .

So I don't have one to control the original crossover gap.

On the other hand I am mounting 900 cylinder heads with 900ie camshafts, I could control the crossing on it.

 

[koko64]

I'm curious if it's just a cam spec or combustion chamber spec issue.

I thought the 900V cams might be enough for 800cc.