Finally getting around to timing up my 1000DS engine, running Ducati Kamna "Sport" camshafts as seen here Timing spec sheet states that we should time to the following: (With 1mm valve lift) Intake open: 34 Degrees before TDC Intake close: 66 Degrees after BDC Exhaust open: 54 degrees before BDC Exhaust close: 22 degrees after TDC I've tried to get close to these numbers, however I'm encouting a problem, I've found that: Intake open: 34 Degrees before TDC but it actually closers at 57 degrees after BDC, not the 66 as suggested. Exhaust is similar, I have timed it to open at 54 degrees before BDC, but it closes at 8 degrees after TDC, not 22. Seems a good way out. I've emailed Kamna but to be frank, their responses to previous questions have been really quite slow and I didn't hear for a month or so. I can't call them as they are a German company. Has anyone had experience with 2V camshafts not being able to be timed to the spec sheet? Not sure if I should split the difference or what! All a bit confusing. Any help is very much appreciated! Feel free to see full spec sheet here attached.
First off, why cant you call them? They probably speak perfect english. I would be suspicious of the valve clearances. If its not this then something more expensive is wrong.
I'll give them a try on Friday, from what I'd heard they only occasionally have an English speaker but you are right it's worth a bash! These cams run without the closing spring so I do find it trickier to check the valve clearances as opposed to with the springs. My first L Twin so I'm sure I'm not as adept at clearances as I will be. I had to buy a new feeler gauge as I didn't have one small enough to measure the 0.03mm gap required. Pretty crazy tolerances!
As you can imagine, if the clearances are wrong the cam will open the valves at a different point to what you intended, and therefore they will be open for more or less number of degrees.
I had an issue with oil getting into the combustion chamber of the Darmah after a rebuild and I thought that one of the suspects might have been the uprated oil pump I bought off the same guys, Ducati Kaemna. So I sent them an email explaining what was happening & my thoughts and also indicating I wasn't trying to implicate anything was their fault, and they couldn't have been more interested, concerned or helpful. I found them top guys. Btw it wasn't the pump but piston rings & a rebore sorted it.
That's really great to hear. I've emailed across a few days ago, not had chance to call due to nightshifts but I'll be giving them a bell tomorrow if I don't hear. I would put money on myself making a mistake somewhere or misreading something, but I've been looking at the problem too long to see the wood through the trees. Did they take long to email back to you out of interest? Double checked my clearance, just done the vertical intake for now as I'm only on lunch from nights! I did infact change my opening shim. I was sitting at 0.15mm, now sitting exactly at 0.12mm. Closing shim is at 0.02mm as opposed to the 0.03mm, so I'll reconvene on that tomorrow, although I can't imagine it being too far out with these clearances. I've double, triple checked these, even watched Brad's video prior to remind myself of anything I may miss. Unfortunately, the timing itself hasn't changed at all. We are sitting exactly the same both opening and closing on the intake valve, no difference whatsoever! I suspect I'm missing something.
Sorry to ask the obvious, but you are measuring the degrees at 1mm of valve lift with a dial gauge accurately mounted in line with the valve direction of travel, aren’t you?
Are you taking the valve clearances into account? If you measure at 1mm valve lift, but with a 0.15mm clearance, you're effectively measuring 1.15mm lift nett. In effect, you're picking up the beginning of the lift at the wrong point on the cam lobe. When timing up in the past, I've taken up the valve clearance with a feeler gauge.
Definitely don't apologize! I fully expect it to be something obvious and anything I should double check I will do. This is my setup currently: https://imgur.com/RqByLNt It's not the "official" tool of course, too pricey for my likes. It's following the rocker arm but does follow the valve. I can make adjustments if needed! So I've just ran over again but with 0.85mm as opposed to 1mm of clearance. The reason I didn't previously was because the sheet states "1mm valve lift without clearance" but that could mean that you need to take the clearance into account yourself. Forgive me if I'm getting confused, but if I do take the clearance into account one side, I'd need to do the same the other side anyway. So I'd get 3 degrees later opening and 3 degrees later closing, but the intake is still open for 9 degrees shorter than it should be. Also thank you everyone for the assistance!
"1mm lift without clearance" is just that. No clearance. The easiest way is to slide a feeler gauge in there rather than trying to account for it. 0.85mm is the wrong way? If you have 0.15 clearance, then to measure at 1mm lift, you'd need 1.15mm lift. If the issue is the overall duration, then that's an issue with the lobe grind. However, having the clearance issue means the rocker isn't beginning to act on the valve as early as it should. Stick a feeler gauge in and try that.
Okay, just done that. I measured the 1mm lift with a feeler gauge inserted to take up any clearance, exact same results to the degree. I then double checked my valve clearance on the horizontal cylinder and attempted to time that. Intake valve again so I can cross compare. Results below: Kamna Intake 34 degrees before TDC 66 degrees after BDC Intake Duration 280 degrees Vertical (Intake) 34 degrees before TDC 57 degrees after BDC Intake Duration 271 degrees Horizontal (Intake) 32 degrees before TDC 58 degrees after BDC Intake Duration 270 degrees So the duration on these camshafts, unless I'm going awry, appears to be 9/10 degrees short on the intake duration...
Argh! Figured as much. I'll call Kamna tomorrow and try out my German lingo. I'm still somewhat surprised, 10 degrees out is a heck of a lot, I was expecting perhaps 1 or 2, but 10 would surely alter the characteristics massively. The fact they are both out to a similar degree at least means I'm either making the same mistake twice or that the camshafts are slightly different to specs Just called Ducati Kamna, guy I spoke to said he spoke a "little" English but honestly he outdid me. Instantly knew what I was referring to, said the design changed a year ago. Get the openings right and the rest will follow. Easy as that! Glad I wasn't going mental. Thanks for everyones help, hope this helps anyone else who has a similar issue!
Neither, I bought the sport cams, they supplied the sport cams. They failed to notify me that the sport cams had changed however, and included a spec sheet with the "old" specs. So the timings were all wrong! I'm happy it's now resolved and I should've called earlier and not doubted my findings. Live and learn!
Just for a giggle I had a go at measuring the cam timing on the Darmah.... and could get absolutely nowhere near close to any of the specs. Just miles & miles out, you know summat like 14 degrees out on opening & 27 degrees out on closing... So fair play for accurately measuring them
Never know, could be in a similar position to me and the cams aren't ever gonna hit the timing specs! Thank you though, first time timing up an L twin. Really enjoyed the process as a whole, but it's fought me at every turn!
The cams in bevels are notoriously dreadful plus other ghastly 1970s machining, non parallel rocker spindle holes anyone, introduce errors all over the place. And that's not including my err... complete lack of the accurate tools required for the job. As I say I did it more for a just to see & a giggle than anything else.
