Great info, thanks for the thoughtful response.

Next time I post on this particular thread it'll be to rant/rave about my own MCM.

 

Well, I guess I lied about posting again in this thread, but I just found a KLR 250 manual online, which I said I'd look for earlier. This is the bike that shares its engine with the Mojave and is essentially the technological predecessor to the KLX 250/300 engine. It shares so many similarities (except the valve timing!!) with the KLX I feel this info is relevant to those looking to understand what the MCM does. Note the super advanced intake valve timing of 41 deg BTDC on the first model, and the Mojave matching 31 deg on the later models.

Also of note is the incredible horsepower claim (this HAS to be at the crank ).

So again, these KLR, KSF, KFX engines share similar bore, stroke, #of valves, compression, and liquid cooling with the KLX, while the valve timing and rocker arms between cams and valves are the biggest differences.

 

Ok, if I'm doing the math correctly, it looks like the MCM creates timings nearly identical to the KL250-D6 and the Mojave?
I say nearly because it looks like the MCM exhaust events are a tad mo-retarded ?

So the takeaway is that the MCM is not going "off book" with cam timing ?

 

Yeah, if us both are doing the math right, it seems so. Even the second ignition timing given for the KLX (not sure if the AU model symbol refers to the first or second set of ig timing given) is very close, 10 to 35 deg BTDC, only difference is that the KLR/Mojave advances the ignition to 35 @ 3000rpm instead of 5000.

MCM Cam timing def looks like its not "off book", of course who knows how the differences in cam lobe shapes, valve sizes and lengths, and slight difference in ignition timing all play in.

Just to make sure Im seeing this right-- "Advancing" the intake on the MCM is actually making it open even earlier (farther away) than it does from TDC, and "Retarding" the exhaust is making it open even later (farther) past BDC, correct?

All very interesting stuff to contemplate..

 

Yes, I concur with intake cam advance increasing the "number" of degrees BTDC and retarding the exhaust cam is also increasing the "number" of degrees BBDC..

But we really need Zombie or someone else well versed in cam timings to provide guidance.

I or someone needs to condense your data into an easy-to-compare "form"..

 

Heres a little spreadsheet I put together to condense and compare cam timing from KLX 250s stock vs. Marcelino Cam Mod vs. KSF 250 Mojave vs KLR 600 ( I had the 600 manual handy so I figured why not throw it in ).

I really wanted to look at the KFX/LTZ 400 quad timing, but the service manual I found did not show it. Hope this helps clarify what the MCM is really doing vs. stock timings. I think I have all the calculations for full open correct, if any errors are pointed out I will correct it.

 

Here is all the guidance you need:

Degree the cams after your MCM mod

Until then, all the discussion regarding valve timing is nothing more than speculation.

 

You are right on, I agree-- but if the bolt holes on the cam gears are actually 2.5 teeth apart, and there are actually 34 teeth per gear, the MCM column on this chart will be accurate unless I fat-fingered something.

More less just helps folks (myself included) to visualize what you are actually doing to the timing by doing the mod as Marcelino describes.

 

Theoretical cam timing, as what the chart would be called, will be accurate from an engineering standpoint, the actual intended design. Degree wheel checking has the variables of valve clearance differences and the actual machining process tolerances that will play into that. Those would likely have minimal effect in consideration for a play bike. For a racer trying to eek out the last tenth of a horsepower because it might be that difference in getting to the finish line first, degreeing in a cam is the best way.

Obviously the intent from Kawasaki wasn't too big on perfection in cam timing, otherwise we'd have slotted cam bolt holes to make the adjustments, since even the height of the cylinder and machining of the head would affect cam timing. Tolerance stacking of machined parts will affect the timing, but clearly no slotted holes indicates Kawasaki wasn't too worried about it for us non-racers... maybe even for the racers.

Side note trivia:

Back in the early days of 600 super sport, when the bikes had to be almost stock, Honda racing went through a pile of production engine parts to find the ones with the machining tolerance variation that provided just a shade more of "that good stuff". Kept them within the "stock" parts rules. They found the box stock cam with primo profile and heads with the best flow without having to touch them which would have been illegal. I think Honda did "cheat" a bit with some modified muffler internals for better flow though. Supposedly a bit of "detailing" done during the muffler build at the plant.

Suffice it to say Honda kicked everyone's butt in the first few years.

 

And that's why I try to stay out of these conversations.

No offence intended, but most of what you just said is either wrong, or irrelevant to the discussion.