Thanks AussieCheech..

You guys have got to stop looking to Youtube for MCM help ! None of the youtube vids peeps have presented to us here are accurate ! The idea that just retarding the exhaust cam is ok and is all that is needed to improve top end is sooooo very wrong ! Does it really take a rocket scientist to understand that extending the power stroke with a later exhaust valve opening DOES NOT improve top end , it improves BOTTOM HALF rpm range power ! By extending the power stroke, more power can be made IF additional air/fuel can be introduced into the combustion chamber - which is what advancing the intake cam does ! Without introducing an increase of AF to make good use of the extra work potential made available with the extended power stroke, the extended power stroke is useless !

One aspect of a correctly done MCM, that has not been talked about, is the experience of the initial fire-up to idle. The idle exhaust note is so different, powerful, and visceral that you just let it sit there idling, marveling over it and admiring your "new" bikes' sound...

 

If you have studied the MCM (mine and KLX678's documents and posts) and your engine is "locked down" and cannot rotate during the MCM, you really shouldn't be able to go wrong. If your end result does not look like the pictures we offer, you've got to keep at it until it does ..

 

Yall don't forget to print off my MCM PDF below, on my signature line !!!!

 

Thanks for the quick response xster. My reference to the vid was only to note that he jimmied off the sprocket. Never intended to do only one, and doing both as per the photo's. Locking the engine, great idea. I hadn't noticed your signature PDF. Thanks mate, will check it out.

 

There isno mark on the chain. I is a chain there is no start and end. The chain is just a chain going around the sprockets, all that matters is the positioning of the crank/piston and the cams. The only thing I was careful of was not dropping the chain down into the engine so I didn't have to fish it out. Even if you did I believe it can be retrieved with one of those magnet wands. So forget about the chain.

All you need to be concerned with is that the crank is aligned with the T mark in the sighting hole on the left side stator cover, indicating the crank/piston is at TDC. Then you make sure the sprocket marks are lined up as illustrated in the instructions when the whole thing is fitted.

 

I meant add a mark with a white marker pen on the chain and the sprocket just so that you could see the 2 link move, and if something went wrong (like maybe dropping the chain) then you could put everything back exactly as it was, and start again. But then again, as long as the marks are correct I suppose it doesn't matter. Pretty sure I am good to go now.

Next dumb question, what is the easiest way to lock the motor?

Cheech

 

Don't overthink what is going on. You can do the chain mark, but now you have to make sure the chain doesn't get off by a tooth on the crank - the reason why I say don't get all wound up on the cam chain. Just realize what you need to have happen mechanically.

• Break loose the cam sprocket bolts,
• Get the stator T mark aligned with the mark in the cover with the cams at TDC valves closed,
• Remove the tensioner if it is the automatic one, see the manual, or slightly back off the adjustment on a manual tensioner to get a bit of play in the cam chain
• Take the cam cap off (check valve clearances if doing the valves now)
• Pull the cams,
• Move the sprockets on the cams
• Replace the cams with the marks at the proper position per the pictures with the play out of the front run of the sprockets.
• Reinsert the OEM tensioner or if a manual tensioner, adjust play out, to verify proper cam placement.
• Torque the cam cap in place in the sequence given in the manual, and put on the cam cover
• If you have a manual tensioner readjust it for the cold set, finger tightened then backed off about 1/8-1/4 turn.
• Important - carefully with spark plug still removed, turn over the engine two full turns very slowly to make sure the valves do not hit the piston. Again, just a safety measure. If you feel the crank stop against something, it is possible the cams are not properly timed and the valves are against the piston. Do not crank the engine over with the starter or force it with a breaker bar. If you follow the directions properly this will only be a formality to be absolutely sure of no contact.

Notice you need to make sure and verify the cam and crank position a couple times - redundancy to make sure all is correct. Kind of like measure twice cut once.
You don't actually lock the engine. Pull the plug and turn it to TDC based on the mark you will see in the small port on the stator cover. Align the mark on the case with the stator mark. It will stay where it is just fine while you do the cam work. Use the pictures both KLXter has in his signature and the document in my signature. If you are off at all it is quite visible and obvious. I can assure you of that, I fought with doing it on my bike. I say fought, because it seemed every time I would put the cams in I would have moved one or the other the wrong way! I can tell you if you are off a tooth it will be quite clear in comparison to the pictures. The one tip is when you get the cams in place it should be checked with the chain pulled snug on the front run. Verify it again after you install or adjust the cam chain tensioner. Check the T mark alignment and look at the marks on the sprockets in comparison to the pictures. If all is good - all is good.

It is just a case of getting the cams in right. Not hard, just figuring which way you need to rotate them and getting it right. Took me like four tries, just couldn't seem to do it right. I found it much easier than I ever thought it would be. I also did the valve clearances at the same time.

 

2 questions please. What size allen key are the sprocket bolts? Will need to buy the socket for my torque wrench. And why do we have to take the cams out?

The pictures in the manual show that if I am just disabling the KACR by removing the spring, then I can access the spring whilst the cam is still in there. And for moving the sprockets, for intake I could just slide the sprocket off the cam, rotate the cam 2 teeth counterclockwise, slide the sprocket back on the cam, advance the cam 10 degrees by moving the cam half a tooth to line up the hole, and put back screws. Then the opposite direction for exhaust.

Is there any reason this would not work? Would be faster and less chance of stuffing it up.

Cheech

 

You can certainly try doing the manipulations without removing the cam saddle and the cams - the saddle casting goes over the top of the cam chain and gets in the way of your manipulations.. If you give up, just pull the saddle off and get on with it..

 

Righto, MCM done. I completed the mod without removing the cam cover. As the bike is still under warranty I wanted to touch as little as possible. I only had to move the fan for better access. Left petrol tank on as there was just enough room to remove the engine cover, and everything is from the side access, not above.

Sequence

• Remove spring from KACR. Can easily access it.
• Remove cam chain tensioner adjustment bolt and spring.
• Add marks. I also marked the chain so that I was sure I only moved 2 teeth. The exhaust side shows this clearer.
• Set to TDC and remove bolts. One sprocket at a time. I couldn't clearly see the sideways T mark (as per the manual), but knew I had TDC as the IN and EX were right way up and the cams were pointing away from each other and up.
• Ease the sprocket off the cam with a screwdriver. The sprocket will drop a bit due to tension of the chain adjuster. I tried to keep the chain reasonably tight so that the chain didn't come off the bottom or off the cam chain guide. Don't know if it could do this, but wasn't taking any chances. I also didn't want the chain adjuster to have a chance of moving in another notch. In reflection I probably would have been better to remove the tensioner assembly completely, and add back in after the sprocket moves.
• Rotate the cam 2 teeth counterclockwise for inlet and put the sprocket back on the cam. This was pretty easy to get back on with a screwdriver as a lever between the sprocket and the cam. Conveniently there is a gap between the 2 parts to do your levering. repeat for ex but clockwise.
• Advance/retard the cams the half a tooth needed to line up the bolt holes.Add back in your bolts and tension up. Don't skip the fact that the bolts require non permanent locktite. I used 243 as it is better in the presence of oil.
• Re-assemble, manually turn over with sparkplug removed, Then turn over with key, Add spark plug and start. I gave it about 3 hours as 243 is about 60% strength after 3 hours, then went for a ride.

Took me about 2 hours start to finish.

Took it for a run in the mountains and certainly feels different. Not arm stretching, but definitely an improvement, and needing less throttle for the same acceleration. Maybe faster reacting to throttle. The note is different as well. Seems to actually sound like a bigger motor. A bit easier to get the front wheel up, and has the low down torque, that on a steep climb that I normally took in 2nd, I took it in 3rd and it didn't even blink. Lots of potential to get me in more trouble with my right wrist having a higher expectation compared to my actual skill level... I don't think it is running lean, but may respond to some carby adjustments. On the ride home I tested pulling out the choke while cruising at 7000 rpm, and there was no change at all. No rev change and no speed change. Read that an indication of lean is if it picks up with applying choke. Does that sound about right for the mix? I don't know a lot about carby tuning and behavior.

Anyway, happy I got the mod done. Thanks all for your assistance. With all the mods, I think it is closer to a DRZ 400 in power than the original stock bike. I actually think I won't have a need for any more power.