Mine is 2009 UK efi model. Do you still say disable the acr? If so that's music to my ears.

 

If you pull the spring and it doesn't work like you want you can always put it back on. I think it will do fine. I think you can bolt on the cam cap then spin it over before putting everything back on to see how it spins without the CR.

 

If you do the MCM, pulling the spring or removing, repositioning, and reinstalling the KACR is PART OF THE MCM !!!!!

For many years we have been doing the MCM - and one or the other of the above.. This is not experimental ! If it was, I would be the first to say so..

You would never install a new inner tube and not air up the tire - doing the MCM without addressing the KACR component (of the MCM) is exactly the same thing, your doing something (that will work perfectly) and not doing it completely !

 

I got a around same time thailand EFI model(dtracker 250) and disabling the acr made 0 difference to starting. I'll get around to doing the mcm one of these weekends but the acr is disabled in mine already, left in place, 0 effect on anything starts up just the same.

Sure it could make some difference after the mcm. but I don't think it will make any difference to how well the bike starts even then and loads of people just disable it or remove the whole contraption from the cam and never put it back. I don't think it will make any sort of measurable difference to the life of the starter or battery either (I think there's some legacy engineering story on why it's left on the 250 bikes with electric starters..). I just don't see the inability to push it out and move it to the proper position as any sort of reason to not do the mcm, when you can seemingly just disable it with 0 practical effect reported by anyone.

 

FWIW, I didn't do anything to the ACR. It still starts up the same, hot or cold.

 

Gronk, from what we know about the actual mechanical problem (that anyone can clearly see) cause by stock KACR settings and the MCM, your situation surely indicates that 1). Your KACR was and is, nonfunctional. 2). You did not retard the exhaust cam correctly, or at all, when you did the MCM.

Not addressing the KACR aspect of the MCM mod is unacceptable - as ignoring this procedure has proven ill-effects on the ability to start your engine anytime it is warm/hot..

 

Yeah not doing anything to it is not said to be an option, however just taking the spring out is simple and should be enough to disable it. also I guess if the spring is very worn it would disable itself even by spinning just by the starter. mine was so weak when I took it out that I don't really see how it could have been much anything to be honest (like, I don't see how it a spring that weak could actuate anything even with leverage from the mechanism).

however, if you're sure you did the mcm on the exhaust side as well and did absolutely nothing to the kacr and it still starts just fine then I would just leave it as it is. it's not going to be doing anything once the bike is running.

 

Yep, just remove the spring.. I just don't want peeps thinking they can ignore the KACR when doing the MCM.. They'd have to go back in and pull the spring after they get "stuck" somewhere waiting for their engine to cool off - or worse if they run down the battery trying to start it..

 

Realize what the compression release does, it lets some of the compression to bleed off, also it works only at low rpm to get the engine to start to spin easier. I believe it is only effective up to around 800 rpm or so, not sure. The spring holds the release to crack the valve, so too strong a spring would hold the valve open longer. No spring, no valve lift for compression release. It seems backwards, but it's not.

Key point though, the compression release has pretty well been proven by riders who understand the function, to be unnecessary. The starter can easily spin the 250 up, riders will also tell you it will do fine on the big bores too, without any compression release. Take it on faith, get rid of the spring. It will work fine

 

I am about to do the MCM on my new 2018 250S. Have already read most of the thread, as well as a few others. Yet to see a picture that has a mark on the chain and matching location on the sprocket. I thought you would want to mark them so that you can check that the chain has moved 2 links just in case something moves accidentally? Or is it not necessary? Are there any tricks to rotating the chain the 2 links? I saw a youtube of someone doing just the exhaust (for top end), and he jimmied the sprocket off to rotate it. Is this needed, or is there enough slack in the chain to move it with the cam on?

klx678, on the doc in your signature, point 7 only mentions the small amount counter clockwise. Might be a dumb question and obvious when I do it, but assuming this would mean

Remove the bolts from the sprocket on the intake cam, slide sprocket off and rotate 2 links counter clockwise and slide back on, rotate the sprocket counterclockwise the small amount it takes to get the bolts into the EX holes and snug them up.

Is that right?

By the way, thanks for preserving the file. It is also great that you and KLXter are still helping out. 10 years with the mod, so additional proof that there are no long term issues with the mod.

Cheech