KLX 250 ( 300 ) camshaft mod by Marcelino
#462
07-28-2013 | 08:06 PM
Junior Member
1st Gear Member
Joined: Jul 2013
Posts: 14
Jules, You are correct in your thoughts about the intake cam only. I have, basically, a machine shop equipped well enough to allow me to build a collar to support the cam in a correct and safe manner.
I also port matched the header opening to the exhaust port. Easy to do if you have a die grinder or a lot of time and a good dremel. If you do this, do not grind all the way through the weld or you'll ruin your header.
I assume you've read all my previous posts - Yesterday I installed the #132 main jet from the kit. This was because the Dyno pull indicated a lean A/F curve. The bike pulls even harder now. I guess I'll pay for another Dyno pull tomorrow to verify my seat-of-the-pants impression.
I also port matched the header opening to the exhaust port. Easy to do if you have a die grinder or a lot of time and a good dremel. If you do this, do not grind all the way through the weld or you'll ruin your header.
I assume you've read all my previous posts - Yesterday I installed the #132 main jet from the kit. This was because the Dyno pull indicated a lean A/F curve. The bike pulls even harder now. I guess I'll pay for another Dyno pull tomorrow to verify my seat-of-the-pants impression.
For building the collar to support the cam I was planning on drilling a hole the correct size in a piece of plate then cutting the plate in half. I figure I can re-assemble it around the cam then bolt both plates together. Sound feasible?
What problems did you have supporting the ACR? It doesn't seem to have a flat end to just lay it on while beating the cam back on. Normally with this stuff I preheat one part to about 250 in the oven while freezing the other part. Not sure how well that would work here but I've had good luck in the past.
Did you need/use brass anywhere? I can borrow a brass plate from a guy if needed, I'd have to ask around more to try and find a brass hammer.
#463
07-28-2013 | 08:44 PM
Senior Member
Joined: Jun 2013
Posts: 3,231
From: North Texas
1st Gear Member
Jules, that is exactly how I built the collar - out of heavy plate steel. I had a buddy hold the collar on the cam while I drifted out the ACR . This was performed on a large vise. I used a large steel punch and did not dent or damage the ACR. (BTW, I only saw one area on the cam that was safe to put the collar on.)
I banged the ACR back into the cam - I supported the ACR and whacked the end of the cam to reinstall it. While I did not use brass hammers or drifts, I did insulate the cam from the hammer with wood. I hate to admit that I used a pile of rags under the ACR. You should find a better way... I would not do it that way again. I should have at least cooled the ACR and heated the cam - as you should do....
I think I can tell by reading between the lines that you can do this mod. Once you've experienced doing it you can easily reverse it. Please be careful. If your near North Texas I'll help you.
I banged the ACR back into the cam - I supported the ACR and whacked the end of the cam to reinstall it. While I did not use brass hammers or drifts, I did insulate the cam from the hammer with wood. I hate to admit that I used a pile of rags under the ACR. You should find a better way... I would not do it that way again. I should have at least cooled the ACR and heated the cam - as you should do....
I think I can tell by reading between the lines that you can do this mod. Once you've experienced doing it you can easily reverse it. Please be careful. If your near North Texas I'll help you.
#465
07-28-2013 | 10:56 PM
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1st Gear Member
Joined: Jul 2013
Posts: 14
Klxster, I think you about covered everything. It seems like it'll be easy once I get parts in front of me. Stuff like this always looks harder in pictures.
The biggest hurdle for me right now is that the bike is about a week old and has 350 miles on it. Usually I wait a few thousand at least before ripping stuff apart.
Thanks a lot man. I'll let you know how it goes once I get into it. Just ordered the jets and exhaust on friday, no sense tearing into anything until I have them here.
The biggest hurdle for me right now is that the bike is about a week old and has 350 miles on it. Usually I wait a few thousand at least before ripping stuff apart.
Thanks a lot man. I'll let you know how it goes once I get into it. Just ordered the jets and exhaust on friday, no sense tearing into anything until I have them here.
#466
07-28-2013 | 11:14 PM
Senior Member
Joined: Jun 2013
Posts: 3,231
From: North Texas
1st Gear Member
That's more miles than mine had when I did the mod... I love working on new engines - no sludge or gunk or hardened, stuck, gaskets... I kinda had to git-er-done as my son wanted to sell the KLX (and refused to use it) after his first ride on it due to lack of power and a wimpy sounding exhaust.. He likes it now.. Damned kids..
#467
07-29-2013 | 10:12 AM
Member
1st Gear Member
Joined: Aug 2012
Posts: 71
From: pattaya, thailand
Just read the whole thread twice, wanted to make sure of a couple points before I go through with it. Note that I currently have a stock 2012, and will be adding a DG slip-on and removing the airbox lid at the same time. + jetting of course.
1. Doing only the intake side is a viable alternative, and gives some power increase but not full potential, correct?
2. I understand the ACR mod, but have not seen a good how-to pictorial. I'm not positive if I would try it myself or take it to a shop. Either way I'd like to be able to show the shop exactly what needs done rather than them blindly figure it out. I've lost faith in repair shops over the years.
Am I correct in thinking that the cam itself is hollow, and the ACR is acting like a 'cap' on the end? So basically secure the cam then push the ACR out from the inside, then turn and press the whole assembly back together? That seems easy enough. It also sounds like any good machine shop should be able to do the work, or even be a 'home brew' solution with a few different options.
Kansas-klx talks about a homebrew method using a bolt, chunk of metal, and grease. Seems like it would work, as it did for him. How is it going back on? I'm picturing just throwing the entire assembly in a press and the ACR just sliding back into place. Not sure how much pressure is needed, as I have a homemade press type jig that uses a bottle jack. It's crude but has gotten the job done before.
3. As much as I don't want to admit it a big bore kit might be in my future. Not sure when though. Would it be logical for me to do the intake side only, then if and when I do the BB kit just put everything back? Would save on ACR work X2 at least, as the cam mod doesn't seem to help once you go big bore. Perhaps the ACR work is easier than I'm picturing though. Mainly I haven't seen any talk of just how tight it is on there.
Thanks for any help.
1. Doing only the intake side is a viable alternative, and gives some power increase but not full potential, correct?
2. I understand the ACR mod, but have not seen a good how-to pictorial. I'm not positive if I would try it myself or take it to a shop. Either way I'd like to be able to show the shop exactly what needs done rather than them blindly figure it out. I've lost faith in repair shops over the years.
Am I correct in thinking that the cam itself is hollow, and the ACR is acting like a 'cap' on the end? So basically secure the cam then push the ACR out from the inside, then turn and press the whole assembly back together? That seems easy enough. It also sounds like any good machine shop should be able to do the work, or even be a 'home brew' solution with a few different options.
Kansas-klx talks about a homebrew method using a bolt, chunk of metal, and grease. Seems like it would work, as it did for him. How is it going back on? I'm picturing just throwing the entire assembly in a press and the ACR just sliding back into place. Not sure how much pressure is needed, as I have a homemade press type jig that uses a bottle jack. It's crude but has gotten the job done before.
3. As much as I don't want to admit it a big bore kit might be in my future. Not sure when though. Would it be logical for me to do the intake side only, then if and when I do the BB kit just put everything back? Would save on ACR work X2 at least, as the cam mod doesn't seem to help once you go big bore. Perhaps the ACR work is easier than I'm picturing though. Mainly I haven't seen any talk of just how tight it is on there.
Thanks for any help.
#468
07-29-2013 | 11:09 PM
Junior Member
1st Gear Member
Joined: Jul 2013
Posts: 14
No kids for me, but I think that if I bought my son a bike, and he refused to use said bike, I would simply have myself a new bike and he would have exactly what he had before, meaning nothing.
Sounds like it worked out though, and you got good performance gains cheaply while convincing me to do the same.
Once I get it out I think I have 2 good options now. Machine shop is the backup plan, I have a few good ideas on where to go. If Klxster's method works for me that'll be even better.
Thank you for the pictures.
#469
07-30-2013 | 03:47 PM
Senior Member
Joined: Jan 2013
Posts: 179
From: Denmark
1st Gear Member
Im taking my bike to a Kawa shop that gets good reviews for its 6000 kilometer checkup in about a week.
2009 EFI KLX250, stock except for KDX200 snorkel.
I want them to make the Cam mod while the bike is there.
I read the entire thread and gathered the info to put in a document for them that I can print out.
A couple of questions:
1) If I want to go to a big bore kit at some later time, is the mod easily reversible? Anything I should be aware of here?
2) Some people said the ACR mod is not neccesary. Whats the verdict on this?
3) Anything else I shouldnt forget to tell the shop? Tips, hints, ect...
2009 EFI KLX250, stock except for KDX200 snorkel.
I want them to make the Cam mod while the bike is there.
I read the entire thread and gathered the info to put in a document for them that I can print out.
A couple of questions:
1) If I want to go to a big bore kit at some later time, is the mod easily reversible? Anything I should be aware of here?
2) Some people said the ACR mod is not neccesary. Whats the verdict on this?
3) Anything else I shouldnt forget to tell the shop? Tips, hints, ect...
#470
07-30-2013 | 04:19 PM
Senior Member
Joined: Jun 2013
Posts: 3,231
From: North Texas
1st Gear Member
Is the cam mod needed on the 09's ? I think the last handful of pages here has a reminder post about which years benefit from the mod.
I hope the shop has experience with the cam retime. My Kawasaki dealer did not have the knowledge and would not perform the mod.
I hope the shop has experience with the cam retime. My Kawasaki dealer did not have the knowledge and would not perform the mod.
Im taking my bike to a Kawa shop that gets good reviews for its 6000 kilometer checkup in about a week.
2009 EFI KLX250, stock except for KDX200 snorkel.
I want them to make the Cam mod while the bike is there.
I read the entire thread and gathered the info to put in a document for them that I can print out.
A couple of questions:
1) If I want to go to a big bore kit at some later time, is the mod easily reversible? Anything I should be aware of here? Reversing the mod is the same as peforming it.
2) Some people said the ACR mod is not neccesary. Whats the verdict on this? The ACR reposition is mandatory, if you retime the exhaust cam, for proper hot starting - this information is clear in this thread
3) Anything else I shouldnt forget to tell the shop? Tips, hints, ect..I don't think there's anything else - regarding the cam retime.
2009 EFI KLX250, stock except for KDX200 snorkel.
I want them to make the Cam mod while the bike is there.
I read the entire thread and gathered the info to put in a document for them that I can print out.
A couple of questions:
1) If I want to go to a big bore kit at some later time, is the mod easily reversible? Anything I should be aware of here? Reversing the mod is the same as peforming it.
2) Some people said the ACR mod is not neccesary. Whats the verdict on this? The ACR reposition is mandatory, if you retime the exhaust cam, for proper hot starting - this information is clear in this thread
3) Anything else I shouldnt forget to tell the shop? Tips, hints, ect..I don't think there's anything else - regarding the cam retime.
Last edited by Klxster; 07-30-2013 at 04:37 PM.