I couldnt agree more with doing one mod at a time. Coming from a guy who raced motocross back in the 1970s we worked on our bikes more then we rode them it felt like sometimes. Its always a good idea to make changes in steps thats for sure.

I look at the MCM "mod" as less of a mod really and more of a "correction" to get the lobes to where they should be. I think kawi "neutered" the bike maybe to satisfy the EPA? Dunno. But after reading the guys posts that came up with the MCM, it looks like changing the cam timing, it gets the lobes closer to what other "dirt bikes" lobes are at. I cant remember, 300degs vs 310 or visa versa. Its a pretty safe thing to do thats EZ and what I like, totally reversible.

I MIGHT be putting in a 300cc kit and if I do, MCM is gunna stay. I like my power band where it is right now.

 

For those that can accurately analyze dyno charts, I posted this thread, showing MCM vs Stock Timings performance delta with both bikes using a lidless CVK setup, stock header with slipon.

For those that cannot accurately analyze TRQ charts - Huge increase below 6100 rpm, parity from 6100 - 6500 rpm, slight loss ( max loss is .75 lb ft - if the "wavy chart" was averaged..) from 6500 - to redline.

Adding a full exhaust sytem (FMF, FSW, etc) will make the MCM almost mandatory as low end TRQ is "killed" with full race exhaust and MCM restores most of it..

 

Also, I think many will agree, that those with "Performance Tech & Dyno" knowledge would have fun reading all threads started by Klxster..

 

Thanks!

Happy to know the cams don't need replacing. On that note, I wont be applying the MCM until after I understand the power of the 351 kit for the reasons y'all listed above. However, once shes up and running I am willing to apply it and possibly run a DYNO as a way to reciprocate all the knowledge and help I've gotten from this forum. My cylinder should be arriving today!

I also plan on picking up one of Bill's TM 33/34 carbs! I'm going all in !!

 

Your posts are always entertaining ヾ(＠⌒ー⌒＠)ノ

 

Excuse my ignorance but is only a cleaning required to resolve this issue below?

and is it even an issue? or is this normal wear? Thanks

 

your talking about the carbon build up? yes, pretty normal looking. scrapers, wire wheel, wire brush, Scotchbrite, solvent etc..

check to see if valves leak by pouring a couple tablespoons of mineral spirits thinner in to each port to see if it leaks through. if it leaks then you need to clean up the valves, which may be as simple as lapping

you will also want to check the head's contact surface with a straight edge to see that it is flat . or, put it on a plate of glass & probe it with a feeler gauge. I don't know the limit off hand but a coupe thousandths. you lap the head flat on a plate of glass & wet/dry sandpaper taped to it

 

As far I understand, to check the wear of the valves it's necessary valves to be removed.
For checking and repairing special tools are needed.
I asked machine shop that specializes on engines heads repairing to check the head of my 351 (the head was removed due to another reason).
They used some kind of vacuum machine to check valve tightness and found that it would be good to repair all 4 valves and also valve seats.
Then I got assembled engine head back, put it on and adjusted valve clearances.

 

Definitely talking about the carbon build up.

I just got off the phone with a local shop who specializes in cleaning heads but works mostly on cars. He told me to "get the valve diameter of the stem" so he can let me know whether or not they will be able to perform the job.

Does anyone have this info off top? If not please see image below.

Will I be taking the measurement of the green or red?

Thanks y'all

 

what you want is the diameter of the stem where it rides near the end of the guide.... thats about an inch up the stem from the valve head (red line). that will be the place where there is the most wear. the valve moves about 4-5mm up and down in the guide. the top won't wear appreciably in 30-40,000 miles. even the high wear area doesn't wear much due to the shim/bucket design. what used to wear out valves is the motion of the cam pushing on the stem. modern bucket design eliminates that... the cam pushes the bucket, the bucket moves the valve. the side force is on the bucket (which has a huge surface area). I very much doubt the stem to guide clearance is excessive. when that clearance gets big, the valve will be off center.... it will leak.

what I would do is see if the valves leak using solvent. if not, then call it good... unless you want to replace the seals.

if they leak a little... like weep over a couple minutes, I would lap the valves

if fluid pisses out then the seats & valves need to be faced

if this is the 4000 mile head off the engine in earlier posts I seriously doubt that there is perceptible wear, and my bet would be all parts meet new limits