KLX 250 ( 300 ) camshaft mod by Marcelino

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  #721  
Old 04-10-2015 | 09:02 PM
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I don't advocate sticking a wire onto a rotating mechanism.. Simply removing the spring completely deactivates the KACR.. the entire mechanism presses out - off the camshaft.. I drifted mine off with a large punch and a small sledge hammer - obviously while the camshaft was properly supported.. I certainly would remove that thing permanently if I had to do this over again.
 

Last edited by Klxster; 04-10-2015 at 09:08 PM.
  #722  
Old 04-11-2015 | 06:45 AM
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Originally Posted by Klxster
I don't advocate sticking a wire onto a rotating mechanism.. Simply removing the spring completely deactivates the KACR.. the entire mechanism presses out - off the camshaft.. I drifted mine off with a large punch and a small sledge hammer - obviously while the camshaft was properly supported.. I certainly would remove that thing permanently if I had to do this over again.
Right, the final decision was made to remove KACR by using a press. This is how it looks splitted.
I hope these photos will help others on how to remove KACR.

I performed Marcelino cams mode. My cams are rotated and the exhaust cam is lighter now.
I removed the lid off.

I noticed the engine starts faster now. No mater if it is cold or warm.
Can I do front wheelie now without clutch? No. I haven't notice big difference using new configuration.

if I go on full throttle I notice a slow response (that was before mod too). No matter if my CO2 is connected or disconnected with bypass. I have KLX 250 with fuel injection.
For some reason I still have that throttle delay.

Next, will order EJK controller and will add head pipe and muffler from KX250F.
And probably first I would need to dismantle fuel injection. Just to verify if previous owner haven't made any interesting mods here

My older 1998 Honda XR 250 with carb runs better, throttle response is much much quicker.
 
Attached Thumbnails KLX 250 ( 300 ) camshaft mod by Marcelino-wp_20150410_008.jpg   KLX 250 ( 300 ) camshaft mod by Marcelino-wp_20150410_009.jpg   KLX 250 ( 300 ) camshaft mod by Marcelino-wp_20150410_010.jpg  

Last edited by honda15i; 04-11-2015 at 06:52 AM.
  #723  
Old 04-11-2015 | 01:22 PM
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Originally Posted by Klxster
I don't advocate sticking a wire onto a rotating mechanism.. Simply removing the spring completely deactivates the KACR.. the entire mechanism presses out - off the camshaft.. I drifted mine off with a large punch and a small sledge hammer - obviously while the camshaft was properly supported.. I certainly would remove that thing permanently if I had to do this over again.
Based on sound metallurgical and mechanical engineering properties I do recommend putting a piece of mild steel round wire in the compression release mechanism to lock it in a disengaged position, rather than allow the shoes to flop about unrestrained. It is a sound mechanical practice in this case. Everything is locked in position so there is no movement, but it is still totally reversible. One just needs to look and consider the facts here and make the appropriate bends in the wire to lock it in place. You will destroy something else long before that piece of wire bent one time at each bend will fail.

I put it out there that I used coat hanger, because I knew it would get a rise. Coat hanger is simply round low carbon steel, much like what was likely used to make some parts inside the engine. It just happened to be virtually the perfect cross section OD too. It will bend without fracturing and will stay in place better than the spring itself. I had the spring on a similar CR in my KLX650 come off twice. The only way you will get that wire out of my CR is if you use cutters or bend the snot out of it. There is no way it can come out due to any rotation of the cam. You see, I'm no rookie at this.

But if I have to pull the cams out in the future I will have the whole mess pressed out after finding it wasn't necessary to have it. It is just an appendage remaining from the kick start engine KLX300 and first 250 before e-start. Neither the Honda nor the Yamaha 250s use compression releases on their 250s. It is just an unnecessary complication.
 
  #724  
Old 04-15-2015 | 09:37 PM
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Just did the mod this weekend along with a 13T sprocket, Dynojet Kit, drilled the slide, Installed manual cam chain tensioner and removed airbox lid.

The bike is WAY nicer on the trails now. First gear can still be a little lacking on the steeper hill climbs but I think that's partially a pilot screw adjustment issue - it tends to bog down unless my revs are up and I'm more than 50% throttle. Running DJ124 with no airbox lid @ 1300' ASL, mixture screw was 3 turns out, Needle set on the 4th notch.

It's less punch than I had expected - I was hoping to be able to do power wheelies in first gear and maybe clutch ups in second. No dice.

For next to nothing, I'll take it though. Third gear is actually punchy on the trails now.

I've got the mixture screw at 2.5 turns now, have to test it still though. There was a huge improvement after going from the 3rd notch to the 4'th on the top end. It would fall on its face pretty hard after 7500rpm, it pulls pretty evenly up to 9k now.
 
  #725  
Old 04-15-2015 | 10:26 PM
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pwjm, from my data, I would assess that you are extremely lean from about 6.5K on up. Moving to 4n gives you the much needed fuel in the midrange but cannot compensate for that horribly lean DJ124.. You said you drilled the slide, which DJ kit are you using and what are your exhaust mods? I think I can get you your power wheelies - see my video below..
 
  #726  
Old 04-16-2015 | 01:34 PM
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Originally Posted by Klxster
pwjm, from my data, I would assess that you are extremely lean from about 6.5K on up. Moving to 4n gives you the much needed fuel in the midrange but cannot compensate for that horribly lean DJ124.. You said you drilled the slide, which DJ kit are you using and what are your exhaust mods? I think I can get you your power wheelies - see my video below..
Based on the jetting spreadsheet, we wanted to jet it for my home elevation of 2000' ASL. Seems like most set ups similar to mine for that elevation where using a 124. When I rode it for a few hours at 1300' ASL I didn't notice any decel popping or anything to indicate it was running lean. I'm open to suggestions though.

I'm just using a stock, unmodified exhaust and only the airbox lid removed.

DJ kit is the 2152 for 2009+ klx250s.
 
  #727  
Old 04-16-2015 | 01:58 PM
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pwjm, I'm using a DJ128, needle at 4.5N and fuel screw at 2.5 and I'm at 5k ASL, although I do have an FMF slipon so a main jet size down to account for that and it would be 124 at 5k ASL. I would definitely try a DJ128 at your elevation.

Main Jet Correction

https://www.kawasakiforums.com/forum...-tuning-36018/
 

Last edited by neonarc; 04-16-2015 at 02:01 PM. Reason: added a link
  #728  
Old 04-16-2015 | 03:43 PM
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Originally Posted by neonarc
pwjm, I'm using a DJ128, needle at 4.5N and fuel screw at 2.5 and I'm at 5k ASL, although I do have an FMF slipon so a main jet size down to account for that and it would be 124 at 5k ASL. I would definitely try a DJ128 at your elevation.

Main Jet Correction

https://www.kawasakiforums.com/forum...-tuning-36018/
According to the jet correction chart, I'm actually right in the ballpark at 124. I'll give the 128 a go anyway though.
 
  #729  
Old 04-16-2015 | 04:13 PM
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Pwjm, the jet conversion charts are not usable if your going with DynoJet parts. No one measures a DynoJet main jet correctly.. If you're still skeptical about this, do what I did, call dynojet, ask for a jetting specialist, ask about the online conversion charts.. DJ jets are not simply drilled hunks of brass like Keihins' - they have a tapered "venturi" cross-section.. I'm certainly not saying they're better.. I'm about to have to order a DJ148 and a DJ150 just to try to get my top end to stay under 13.5:1(AFR) at 700' ASL..

Now having said that, I have no data or knowledge about setting up the CVK with no lid and stock exhaust..
 

Last edited by Klxster; 04-16-2015 at 06:44 PM.
  #730  
Old 04-16-2015 | 05:24 PM
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Originally Posted by Klxster
Pwjm, the jet conversion charts are not usable if your going with DynoJet parts. No one measures a DynoJet main jet correctly.. If you still skeptical about this, do what I did, call dynojet, ask for a jetting specialist, ask about the online conversion charts.. DJ jets are not simply drilled hunks of brass like Keihins' - they have a tapered "venturi" cross-section.. I'm certainly not saying they're better.. I'm about to have to order a DJ148 and a DJ150 just to try to get my top end to stay under 13.5:1(AFR) at 700' ASL..

Now having said that, I have no data or knowledge about setting up the CVK with no lid and stock exhaust..

If there was an aftermarket exhaust that's comparable to the stock one noise wise, I'd be all over that. I live in an apartment and just removing the airbox lid is pushing my luck. I'd be able to use my AFR gauge then as well.

Being in an apartment means It's really hard to work on my bike too. It's currently at a close friend's house who just happens to be a bike mechanic by trade. I'll see if he has time to try the 128, but if it's no good we won't have time to swap it back.

When it comes to jetting it seems like people are all over the place: https://docs.google.com/spreadsheets/d/1gx-3lY0k6a9WhvBdxTR0ZkdAHNO_YS7Cd8Ugkn1iDnc/edit


There are people at sea level running a DJ128 with an exhaust and no lid. Contrast that with klxster and neonarc and things don't add up. Either people are way too lean on a constant basis, or these bikes are extremely tolerant of fuel mixtures in both directions.
 


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