So the plug fires on each rotation?
At the top of the intake stroke (not at the beginning of the power stroke) aren't the exht and intake valves open? I would think that would cause a backfire up to the carb.

 

Klxster,

Other than 50mpg, it has been running perfectly and starting easily for the last 5,000 miles.

 

50mpg, really? Seems rich. I get 62 mpg on a BB351, used to get 70 all the time in the stock bore with MCM.

 

See that sounds exactly right to me although I did nothing different. My method for resetting and installing the tensioner was the same every time: push it in, install tensioner with two 8mm bolts, install spring and big bolt, done. It does seem like there was some cam chain hiccup that has been resolved now though. Either way I'm just commuting around town and practicing wheelies(comes up like butter even as is) on the bike so I don't need the extra power for now. I'll probably just wait awhile till I have a good chunk of free time and retry the MCM as well as adjust the jetting, remove the airbox lid, delete the emissions crap and probably adjust the gearing. Before any of that I should really save up for some better tires though. These factory tires are pretty sketchy lol.(I'm used to s21's)

On a side note I guess my bike isn't 100% back to stock. KACR is still disabled and the bike starts up just as fast or faster than before.

 

Wasted spark ignition is actually pretty common I guess. The reason what you're describing doesn't happen is because at the top of the intake stroke there's no fuel(or not enough) in the cylinder yet. From the top of the intake stroke the piston moves down then and only then pulling fuel into the cylinder.

 

Clay, congrats on revealing that the KLX uses a "wasted spark" ignition regime.. Yours is the first revelation of this fact in here.. I believe you misspoke as the wasted spark would be just before the top/end of the exhaust stroke - just prior to the beginning of the intake stroke..

Oldgypsy: If it runs perfect now, you are ready for MCM.. Please do the work with the engine locked down at TDC on the power stroke, re-bolt the cams into their "new gear holes" , reinstall/lay down both cam assemblies in the stock gear position, then rotate each one 2 teeth - intake gear rotates counterclockwise, exhaust gear rotates clockwise. Triple check that the finished retime matches exactly with the pictures on KLX678's google doc.. Replace the cam top casting - Don't over trq the cam top saddle casting bolts - all those bolts are only suppose to have a little trq on them but I cannot remember the exact number.. ...Take care with properly reseting and manipulating the chain tensioner.

Test carefully for problems - Turn the engine over by hand (wrench on the flywheel bolt or spin rear tire) - if ok, then by the starter - if ok, replace plug and start to idle...

 

Last paragraph pretty much true. Singles with the wasted spark can do that. It's all in the cam timing.

As for the tensioner, the damage is not readily apparent at a look. There is a tell tale wear pattern caused by the repeated kicking back and pushing out again of the plunger. I am attaching two pictures of my own 250 tensioner. The one tooth that is eleventh from the right shows a polished edge. That is because the tooth has been rounded. The pawl will also have similar polished edge. The back side shows polishing from the plunger sliding in and out on cam drive deceleration/acceleration.

Some will tell you there are some short cuts, like sticking a screwdriver in the tensioner and jamming it tighter to hook in a tooth further, or loosen the body until you hear it click over, but both are putting excess tension on the cam drive. With only a few thousandths of oil between the plain bearing cam journal in the head and the cam do you want to really make it tight? Adjusting a manual tensioner is easy enough to be far more accurate than either of those methods. The other thing with a manual tensioner is that you KNOW your cam drive is adjusted and will hold adjustment after adjusting per instructions and tightening the lock nut down good and tight.

I know a fair amount about this because of personal experience and seeing this damage on a number of other bikes like my KLX650, a tensioner from a ZX6RR, and a Suzuki GSF1250. I also have had other riders mention this wear pattern too. Does the tensioner work? Just ask here. Seems to be a weak spot on the bike.

Last paragraph pretty much true.

As for the tensioner, the damage is not readily apparent at a look. There is a tell tale wear pattern caused by the repeated kicking back and pushing out again of the plunger. I am attaching two pictures of my own 250 tensioner. The one tooth that is eleventh from the right the first picture, from the left in the second one shows a polished edge. That is because the tooth has been rounded. The pawl will also have similar polished edge. The back side shows polishing from the plunger sliding in and out on cam drive deceleration/acceleration.

Some will tell you there are some short cuts, like sticking a screwdriver in the tensioner and jamming it tighter to hook in a tooth further, or loosen the body until you hear it click over, but both are putting excess tension on the cam drive. With only a few thousandths of oil between the plain bearing cam journal in the head and the cam do you want to really make it tight? Adjusting a manual tensioner is easy enough to be far more accurate than either of those methods. The other thing with a manual tensioner is that you KNOW your cam drive is adjusted and will hold adjustment after adjusting per instructions and tightening the lock nut down good and tight.

I know a fair amount about this because of personal experience and seeing this damage on a number of other bikes like my KLX650, a tensioner from a ZX6RR, and a Suzuki GSF1250. I also have had other riders mention this wear pattern too. Does the tensioner work? Just ask here. Seems to be a weak spot on the bike.

 

Awesome, appreciate the pictures. I wish I had taken a picture of mine but I did examine the teeth and they all looked pretty sharp, but I could be wrong. Maybe before I try the mcm again I'll get a manual one. Are the kreiger ones the go to ones for this bike?

Also for ****s and giggles, here's how badly I messed up the original attempt at the mcm(this picture is at TDC). You can see I used the wrong marks to set the timing.

 

To add to klx678's comments, I was getting an awful noise above approximately 7000 rpm. Sounded like a bent valve or a large gap.
I was running my original auto tensioner after getting a 300 kit and a new timing chain about 1100km ago. After some searching I found my manual tensioner (having moved house) and reinstalled that.
The back of the auto tensioner has a smooth area, not yet shiny, from movement. The teeth look good apart from an area that is cleaner than the surrounding areas.
If it wasn't raining as much today I'd be out 'testing' the adjustment. During the initial adjustment I was being cautious on the cam chain tension and it made that same clacking racket in the video almost exactly. I found that I had a few more turns to get it correctly adjusted. It's unnerving now not to have some kind of clatter but I'm going to have to learn to enjoy it.

 

My riding buddy gets 70 with his stock setup too. I do have the 13 tooth front sprocket and most of my riding is on pretty crappy FS roads so the tire psi is usually in the high teens. I think I checked the color of the sparkplug once and it was a nice looking tan. It runs and starts so good I just assume the mileage is the price of the DJ stage II mod and the 13 tooth sprocket.