Waste of money .....

[Speeddog]

Yes, that's an APTC clutch AFAIK.

[MonsterHPD]

Thanks Speedog!

[Duck-Stew]

Yes, that's an APTC clutch AFAIK.

I can confirm this.

[Orange16]

Why not an APTC clutch?

[stopintime]

Why not an APTC clutch?

Violent on/off on hard take offs. Heavy shock dampening springs under the large primary driven gear brakes too often. Twice on mine. Doesn't happen with 'normal' clutches.

[Orange16]

the 696/796 ones don't have the springs at least.

[MonsterHPD]

the 696/796 ones don't have the springs at least.

Exactly, this one had solid primary gears wihout springs. But the clutch itself does look much mor "sophisticated", with more components and tiny parts in the castings.

It has proven very difficult to find a clutch and matched primary drive crank gear. 

The search goes on ....

[MonsterHPD]

 ... and has been successful:-)

I now have an M620 primary gear and basket, and my hub is the same as on the 620.

In the process, I came across an old 750 motor, the one with the slave cylinder in the right-han cover. The springs in that clutch are the same length as my m800 springs, but are appr. 18 N/mm instead of 13 N/mm. I will use 3 each to start with .....

I´ve spent this wee trying to establish compression ratio, but realized I need measuring equipment; I´ll get a 50 ml burette with a tap so it can be quickly and positively closed.
Anyway, it seems I am at around 10.3 to 10.5 : 1, and that removing the base gasket and some compensating machining of the piston squish bands reduced compression volume by appr 1.8 cm³ and increased compression by appr. 0.4 points. Every little bit helps ....

 

 

[MonsterHPD]

Hello,

yesterday I intended to start assembling the top end of the motor, but it quickly came to a halt. I´ve never been fond of putting the piston pin circlips in place, but so far I have prevailed. However, this time I admitted defeat, at least for the time beeing; the circlips I got are simply too big. My dealer maintains they are the right ones, and I don´t know ....

I ordered P/N 06754 7460, but that P/N has ben replaced by D12111741A, acc to Ducati parts list. I did some measuring and got the following:

M800 (18 mm pin):
Old circlip: D = 20.2 mm
D12111741A: D = 21.2 mm

HYM 1100
STock circlip): D = 21.7 mm (19mm pin)

All measured  perpendicular to the gap.

When I mount this kind of circlips, I usually place the circlip so I can use the "pry-out" notch to lever the circlip into the pin bore and then push it in place in the groove. Usually works OK.
With the 1 mm bigger diameter D12111741A circlip, that´s impossible, the circlip just can´t be levered in, it just turns out of the groove no matter how I try to hold it in place. Might of course just be me, but I can´t get it in place.

Looking into my old DIN standard handbook, the 18 mm pin should usually use a 1.3 mm wire circlip, but 1.5 mm (as here is also listed) Diameter tolerance +1 / -0 mm, so technically these circlips might just be in tolerance, but all others I´ve measured have been close to nominal.

Any experience with this, and potentially advice, would be much appreciated.    

[greenmonster]

Any issues with using old circlips?

[MonsterHPD]

Any issues with using old circlips?

Well, yes and no. Generally speaking, they are cheap and easily obtainable, so I´ve always replaced them as a matter of course. Also, there is always the risk of overstrarining them when mounting / dismounting them, so one cycle less always feel safer.

In this case, I was going to re-use the old ones, but I wanted to see what the Pistal circlips would be like. Got them in 2 days from Kämna, and managed to put them in place without too much drama.
To be fair, I think I might have managed mounting the ones I got from Ducati as well, since I found a better method of mounting the circlips, but I still feel a bit cautious about them since they were so big compared to the original ones, and also compared to the circlips in my stock HYM1100 pistons with 1 mm larger wrist pins. That´s just fine if you get them mounted OK, but it also might increase the risk of permanently deforming them when mounting unless you have proper procedure / tools.   

Tomorrow I plan to put the motor back together, if I and he rest of the family are OK. Hope everyone is doing OK in these troubled times, my thoughts are with anyone struggling, especially due to the Corona virus.

Kind regards,
Torbjörn.   

[koko64]

Best wishes to you too and your family.

[MonsterHPD]

First of all, thanks for the well wishes, and the same to you all.

I had hoped to have the m800 running by now, and technically speaking, I have …. But technically speaking, I´m currently the owner of a 400cc Monstermono.
It took me a bit of research to find the problem, but I think it´s down to a broken injector on the vertical cylinder.  I first thought it was a return of what happened several times on the m900 with Vtwo cams, where it was easy to get the cam one tooth wrong; the motor would still tun, but the header just got lukewarm. In this case, the rear header was stone cold. Spark seemed to be present, and the motor seemed to react slightly to start gas sprayed into the intake of the V cylinder.

On closer inspection, the electrical connector seemed to be broken partially loose from the injector body (on the feed side). I have no idea how that happened, but since the bike ran until I closed it down last fall, and did not run now, the finger points back at me ….

Anyway, should anyone break an injector, don´t buy a new one from Ducati. I checked spare part price, and it is close to the equivalent of USD 600. You do get the fuel T-coupling included, but still … I just ordered a new one from Bike Sport Development in the UK. Still cost me appr. USD 140.
EBay sell them for appr. USD 45, but I suspect that to be Chinaware, nothing I´d care for.

So, right now I´m waiting for the injector. The motor has the new (to me) clutch, porting, no cyl base gasket / machined pistons, and the ST cams. I was aiming at an inlet centerline of 114°, but my first attempt showed 111.5°. Since I don´t really know what would be best, and since the stock cams were at 106°, I decided to leave them at that since they were both almost exactly the same.

I´ve also fitted a fresh set of Bridgestone S22´s, so I am getting anxious to test all that new stuff, hoping not to be disappointed on any account. Fingers crossed.

Anyway, before any running at all, I did a compression test, with the Hor / Vert showing 8.5 bar/125 psi and 9.25 bar/130 psi respectively.

I also did a leak-down test, after a minute or so of one-cylinder running, but that did not yield any useful data at all, both cylinders leaking heavily through the exhaust valves (full valve job by a pro). I put that down to the fresh valve jobs, and my inexperience with leak-down test. I´ll keep testing when I have the motor running.

In order to easily perform the leak-down tests single-handedly, I made a tool to lock down the cam drive wheel:
20200408_173455 by torbjörn bergström, on Flickr

It seems the 4 holes in the drive wheels are not on the exact same CC radius / on generous tolerance; on the 4 sets I checked the tool would fit in one position, but not over the 2 other holes. I did not quite get that “safe-door click” fit I like to get with a tool I´ve made, but it does the job ….         

[koko64]

Glad you're well and busy. Watching to see your results.

What's the standard cranking compression in these motors?
Do you suspect the cranking compression has been lowered by the timing of these hot ST cams? With the timing numbers you originally planned, was your goal to advance the cams to avoid this?

I ask because we once fitted 900ie cams to a very high comp 944 to deliberately bleed off excessive cranking compression  (12.5-13:1). The very high, low rpm cylinder pressure was causing all sorts of issues.

Your numbers appear low and I was expecting 170-180 psi at a guess.

I'm assuming you checked the bikeboy cam specs as a reference for oem timing Vs advancing the cams?

[MonsterHPD]

Thanks :-)

I don´t know what the normal cranking pressure would be, but I got similiar results when I checked the HYM motor after last summer. However, the gauge adaptors i had were very awkward to fit, and somewhat prone to leaking, so I´ve made a new adaptor that´s easier to use. I´m basically doing cranking pressure tests now to get some data and make sure I get reliable results. I would have expected some higher numbers as well though.

I have (of course, excellent info on anything Ducati) read the Bikeboy reports; I´ve chosen inlet CL with an eye to the bike beeing used mostly on track these days. Theoretically, a later inlet closing should favour higher rpm operation. But at this stage, it´s mostly a matter of chosing a sensible value, get the bike running OK and see where to possibly go from there. I ran similiar cam timing on my old m900 with hi-comp pistons and veetwo cams.

I will do frequent cranking pressure tests and leak-down tests on both bikes in order to collect sufficient data to make the tests usable diagnostic tools. I suppose I´ll do some on other bikes as well as referene.