I was really very intimidated by the Marcelino cam mod, reading everything here and even copying the post, pasting to Word, then printing and reading it a few more times.

I have had a few others express the same intimidation and trepidation in attempting this mod.

Thing is when I actually did it and everything came clear, it was quite simple with only the exception of the KACR re-timing being absolutely vague and my big stopper... until I figured out how to disable the KACR without any semi-permanent modification.

I am posting a copy in Google Drive documents free for anyone with the address. Anyone using Google Drive will definitely have access to it and be able to save it to their Google Drive documents and print it off if needed.

It is a condensation and simplification of the process. Other than a few comments it is the steps to do the timing modification and should be pretty clear.

Here is the link:

Marcelino Cam Timing Mod - just the facts folks


Let me know if it is viewable and if any editing is needed. I tried to get it all in there and be far less intimidating.

 

A good consensus. Have you done any rejetting since doing the mod? Supposedly richer jetting is needed to get the max benefit out of it.


Believe it or not I've never seen US style wire coat hangers here...

 

No wire hangers? The link works?

Another source for that kind of wire would be from a welder. Ask for a mild steel rod that can be bent easily without stress cracking. Shouldn't be hard to get. Just get .090" (2.25mm) or slightly smaller.

No rejetting. I think it's really lean on the needle and main. I had a light miss at around 6000 rpm that would smooth out if I pulled the enrichener plunger. I have a 128 main and the 300 needle and will be doing it later.

 

I have an 09 KLX250SF that was originally sold in Dayton Texas. It runs real strong, no airbox lid and I dont hear a howl, and it has other mods from the forums. I want to perfomr this mod on it but first, how can I tell if it was already done?

 

Neonarc, study the pics of the mod, pull the cover, line up on TDC and look at the cam timing marks. It's that simple.

 

Actually easier than that... The intake cam is bolted in at the EX (exhaust) bolt holes on the sprocket and the exhaust cam is bolted in at the IN (intake) bolt holes on the sprocket. You can tell at a glance if the modification has been attempted.

To verify the proper timing turn the engine to TDC compression, the intake sprocket line between the sprockets will be at about 2:00, the exhaust sprocket line will be at about 10:00. The marks will actually be 2-1/2 teeth above the edge of the head - easy.

 

So just to be clear, all of you that have done this mod (both intake and exhaust) have no real intake noise with the lid off? I've just seen a few people that don't seem to notice more noise....I do but the bike runs like it's supposed to and I've checked the sprockets and they look right.

 

Sounds simple enough. Thanks.

 

With mod done well and the lid off, there is intake noise. Without mod and lid off there is roaring, growling, intake noise louder than even the DG-R slip on.

 

Always going to be some intake roar, but apparently not as severe as with standard cam timing. I personally am running the KDX snorkle just due to the possibilities should I eventually end up in some deeper water and, as I already have, hitting sand or the like.