02 KLX300 - ACR/cam timing help!



I have read through several of the threads here and would first off like to thank Brewster for his awesome advice!  I would have never even tried to do my own valve adjustment and carb cleaning without all the great people like him on TT.  My concern is this, the bike was not kick starting when I started to work on it (worked fine for several rides then just kinda crapped out) and through various methods, determined that it was time to check the valves.  My exhaust valves were in spec but my intake valves had zero clearance.  When I went to take the cams out, I realized that the timing marks did not line up to the cases when I had the engine mark at top dead center.  So, I put the timing back to where the EX and IN lines are parallel with the case @ TDC and did the valve adjustment from there.  Afterwards, I stumbled on the ACR timing threads and am now concerned that there may have been a reason for the way it was timed.  I am not sure I understand the ACR timing or even if it is compensated for by moving the cam timing so any advice you can give would be helpful.  Also, since my bike is an 02, is there any way to tell if I have the good or bad ACR on the bike?  Would be better to know before I put her back together and seal it up.






2002 kxl 300

Free mods

Mikuni T36 Pumper Carb

Pom pom's since I am a girl :-)

Congratulations on jumping in and working on your bike!!! Too many folks start off with the idea that it is too complicated...........much of the work on our bikes is not that tricky.

Without worrying about the ACR timing, set your cams to the proper marks with the flywheel lined up with the "T" mark.

Were the cam timing marks close to where they belong when you took them out? If not, the engine may have been at the top of the exhaust stroke instead of at the top of the compression stroke. The cams turn once for each TWO revolutions of the crank.

If you will PM me with your email address, I'l send you two photos of the ACR timing....old timing and "easy kick" timing. The difference is only about 10 degrees of ACR rotation on the exhaust cam.

Oh, thank you for the kind words.

Ride on


Thanks Brewster,


Will PM you my email in a minute.  So I have the top taken off again and after kicking it over several times, the timing looks off again.  Not sure though since you said this above " The cams turn once for each TWO revolutions of the crank."  When I line up the flywheel with the T now, the EX line and IN line are both facing inward (lobes of the cam are pointing inward too) but when I initially timed it, the lines and the lobes were both facing outward.  My cam teeth look ok...what should I look at now to figure out why it appears to be "jumping"?

Ok, snapped a few pics to see if it helps. Right now, i appear to be "jumping" time when i crank over the bike. Took out both tensioners and the top one seems ok but not sure if the tension is enough? I can push it in and when i pop it back out, it stays but am guessing the spring could be worn. The bottom tensioner looks wacky, as the first half of the threads on the bolt looked stripped off (see pic below). When i stick my finger into the cylinder hole, i can feel threads all the way on the outer wall side but only half of the the threads that face the inside are there. Could i have actually busted some off? Also included a pic of my cams....should the dark areas on each cam be of any concern?



Edited by smilonas

I am not sure what you are referring to when you talk about the bottom tensioner and the top tensioner so I am going to assume you mean the two piece assembly that consists of a spring and cap and and a ratcheting stopper rod that is adjusted by the spring pressure. But first things first.


Get the timing mark lined up with the notch on the edge of the hole on the upper hole of the magneto cover.

The cam lobes on the exhaust valves should be facing forward and the lobes on the intake valves should be facing rearward. The marks on the cam gears should be aligned or very nearly aligned with the cylinder head upper surface.

You should be able to count the pins in the timing chain and there should be 32 pins between the marks on the cam gears. This is the same as 16 links with the outside radiused edge lining up to the marks on each cam gear. Note: tolerances sometimes give the appearance of not being in sync but if you move a cam gear one way or another you can really see that it is not set up correctly.

I will assume you have torqued your camshaft cap bolts and have the correct tolerances on your valve settings.

Take your camshaft tensioner and push the rod all the way in. If the little ratched lines are wore off (mine were) it is toast. I replaced mine with a Krieger manual tensioner. You have your choice but it is OEM or an aftermarket purchase before going any farther. Install the first half of the tensioner into the hole in the cylinder housing. Next you install the spring and the chain tension bolt. It has been awhile since I have had mine out but the picture in the service manual looks like the one in your picture in that the threads do not extend the full length of the housing. 

Once you have everything installed the chain should be pretty tight. If by turning the engine over the chain jumps time you have a major issue and more disassembly work in your future.

Put the head cover back on and reinstall anything else that has been removed and try to get it started. Hopefully everything works and you are on your way.


One thing that I do when removing the cams is take some fingernail polish and paint a stripe across the chain and onto the cam gear as an added alignment check when putting it back together. You do have to make sure the chain does not loose its position on the crank gear down below. I use a bungee cord and hook it to the handle bar cross brace.


Hope this helps or at least gives you more information in diagnosing you problem.




You have 36mm pumper carb on your bike. Which one do you have ? Do you put a shim on the back of your tank to allow for clearance ? I tried a BB34 mikuni and it would not work. My bike runs pretty good with the stock unit plus dyno jet kit installed but I know an aftermarket carb would make it better.


Hope you were able to solve your other bike issues.

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