KLX 250 ( 300 ) camshaft mod by Marcelino
With Google you just get to the document, then click on file and make a copy, which will go in your drive and is a separate document in your control.
If there was something to copy from another site you can usually highlight it with a click and drag over it, then right click and copy or do a Ctrl-C to copy it then paste it in a text document like a Google Doc or if you use MS Word, paste it in word.
Like I said, when the KLX Planet was lost and now every Yahoo group, it is too easy for those kind of one-off documents to disappear. Google also doesn't cost anything, just a gmail account, which many have from their cell phone account. I actually have like three of them, one with the school and two that came from the cell phone account and my old Spectrum account. It also allows you to write up your own stuff too and share it if you wish.
If there was something to copy from another site you can usually highlight it with a click and drag over it, then right click and copy or do a Ctrl-C to copy it then paste it in a text document like a Google Doc or if you use MS Word, paste it in word.
Like I said, when the KLX Planet was lost and now every Yahoo group, it is too easy for those kind of one-off documents to disappear. Google also doesn't cost anything, just a gmail account, which many have from their cell phone account. I actually have like three of them, one with the school and two that came from the cell phone account and my old Spectrum account. It also allows you to write up your own stuff too and share it if you wish.
Hopefully someone is still keeping tabs on this thread.
Ive been really struggling with my purchase of the 2018 klx 250 as it is week in comparison to any other 250 on the market.
I came across this but but none of your pictures are available in this thread. Maybe you could update it somehow?
Confirm this mod will up my compression and horsepower slightly?
Bike runs like lawnmower
Ive been really struggling with my purchase of the 2018 klx 250 as it is week in comparison to any other 250 on the market.
I came across this but but none of your pictures are available in this thread. Maybe you could update it somehow?
Confirm this mod will up my compression and horsepower slightly?
Bike runs like lawnmower
Check my signature, it will link to a google doc with the specific work done and the pictures.
I copied them before they were taken down on Marcelino's site. I recommend anyone make a copy of my document in their own google drive (free and easy to do if you have gmail for sure, I have like three accounts, two personal and one school). That way we may never lose information that is of value.
As for how it will work with your bike, I don't know. Do some digging to see if there is an intake box modification like lid removal or snorkel change. Key point here, it is only a 250 and no 250 really feels like a rocket. I rode a CRF250R some years back and was kind of shocked at how slow it seemed compared to any of the two stroke motocrossers I rode. They really feel slow if you get on one after riding a street bike.
Marcelino did this on an EFI bike, so it should definitely help. Hopefully some others who have done EFI bike mods can come and tell you more of what to do.
I copied them before they were taken down on Marcelino's site. I recommend anyone make a copy of my document in their own google drive (free and easy to do if you have gmail for sure, I have like three accounts, two personal and one school). That way we may never lose information that is of value.
As for how it will work with your bike, I don't know. Do some digging to see if there is an intake box modification like lid removal or snorkel change. Key point here, it is only a 250 and no 250 really feels like a rocket. I rode a CRF250R some years back and was kind of shocked at how slow it seemed compared to any of the two stroke motocrossers I rode. They really feel slow if you get on one after riding a street bike.
Marcelino did this on an EFI bike, so it should definitely help. Hopefully some others who have done EFI bike mods can come and tell you more of what to do.
Last edited by klx678; Jan 5, 2020 at 01:26 PM.
Go to the document linked in my signature and see if your cam timing looks like it. As for your cam chain, odds are it is fine, if you are getting a lot of clatter from the cam drive the automatic tensioner is failing. Best thing is to replace it with a manual tensioner and know the adjustment is right and locked in. PM me if interested in one, I make them and a lot of KLX riders are using one, around the world.
Hopefully someone is still keeping tabs on this thread.
Ive been really struggling with my purchase of the 2018 klx 250 as it is week in comparison to any other 250 on the market.
I came across this but but none of your pictures are available in this thread. Maybe you could update it somehow?
Confirm this mod will up my compression and horsepower slightly?
Bike runs like lawnmower
Ive been really struggling with my purchase of the 2018 klx 250 as it is week in comparison to any other 250 on the market.
I came across this but but none of your pictures are available in this thread. Maybe you could update it somehow?
Confirm this mod will up my compression and horsepower slightly?
Bike runs like lawnmower
The original work was done on the European EFI model so it should do well. Read the first few posts by Marcelino to see if they removed the air box lid or snorkel. I have a condensed version of the actual work to be done in the link in my signature. Also instead of relocating the compression release just disable it by removing the spring. Starting will be fine. My 09 model fired up fine in 3 degree F weather without the compression release.
Last edited by klx678; Jan 15, 2020 at 07:15 PM.
The original work was done on the Europeatn EFI model so it should do well. Read the first few posts by Marcelino to see if they removed the air box lid or snorkel. I have a condensed version of the actual work to be done in the link in my signature. Also instead of relocating the compression release just disable it by removing the spring. Starting will be fine. My 09 model fired up fine in 3 degree F weather without the compression release.
I have been concerned about moving it.
Pretty much so. Neither the CRF250L nor the WR250R have compression releases and they work fine. Mine hasn't had one for a couple years now and fires up fine. I tested it at I think 3°F (or 8°F, either way cold as heck) and it fired up quite easily. In summer I frequently don't use choke and if I do it is off choke in like 15 seconds. So no, it really doesn't need the compression release.
Most here disable it by removing the spring, some have it pressed out of the cam. I did my own thing that some don't seem to like, so I won't bother saying what it was - and still is several years on.
Most here disable it by removing the spring, some have it pressed out of the cam. I did my own thing that some don't seem to like, so I won't bother saying what it was - and still is several years on.


