KLX 250 ( 300 ) camshaft mod by Marcelino

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  #1071  
Old 04-06-2020, 02:28 PM
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Make sure the engine is at TDC and the front run of the chain is tight. At that point most slack should be in the back side. I don't remember any tension on the chain when I did the MCM and my valve clearances, but that's been quite a while ago.
 
  #1072  
Old 04-07-2020, 01:56 AM
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Thanks for the prompt replies. Think I lucked out,decided to remove the lower tensioner bolt and it was finger tight.I got the bike in Dec 18 and have yet to ride it .Work and vstrom interfered until now,but our world has changed and now have lots of time! I'm duplicating klxster's mods [bike is even red] and hope to be out by the time roads clean up.Love the forum,learned [learning] at ton,thanks again and everybody stay safe and well!
 
  #1073  
Old 04-07-2020, 05:49 AM
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@klrsidekick , you're in for a real treat when done. It'll run circles around any other KLX , except another KLX that's "up-powered" the same way..

One thot. If you compare your best price for the full FMF system I used (PowerCore 4 + Megabomb) to the Barker system , and the price is not much different, you might go with the Barker for:
1. A possible increase in power over what I had.
2. The "turn down" end cap option that won't melt your turn signal - as the PC4 can/will..
3. The heat shield that comes on the Barker header - the Megabomb does not come with one and the offerings for one are not impressive.

The Barker link: https://barkersexhaust.com/products/...exhaust-system
 
  #1074  
Old 04-08-2020, 01:46 PM
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Hi I think I misspoke slightly in last post,I,d fogotten that Klxster's bike had the megabomb header.After reading the posts last year I decided to stay with the stock header(heat shield,keeping torque down lower, cost etc),so I have stock header with FMF Q4,so plan to go with recipe#1 including MCM,best needle suggestions etc. Upon removing exhaust cam however a problem became evident .I was planning on removing ACR spring and leaving it at that. However the rivets and weights are so loose as to allow enough deflection that the actuator is hitting the follower at higher revs,causing the damage to the follower and consequently the cam (my theory anyway). In the pics the actuator is held open and you can wiggle the cam so it's lower than the base circle! I wonder if this has been seen before as there probably a few bikes with way more miles ( mine has 880mi) running full ACR and no spring on MCM conversion.Spring would make no difference but I would doubt this is the only bike with loose rivets.Any other thoughts or theories would be most welcome.




 
  #1075  
Old 04-09-2020, 01:44 PM
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Hi I submitted a post the other night re MCM progress with two photos, a window popped up thanking me for posting,saying it would be reviewed by a moderator before showing up.Haven't seen it yet however the two pics are the first two when I click on Gallery. Must have done something not right ,so to summarize 1) I misspoke slightly when I mentioned duplicating Klxster's setup,forgeting that he is using a Megabomb.After lots of reading last year I decided to stick with the stock header (torque lower down,heat shield,and cost) and Q4 All else is "best "as in recipe #1 the dyno results sheet.Hope I,m on track. now 2),When I removed the ex cam the left side follower(tappet) had a strange circular marring.See the two pics in the gallery if theyshow up or see a posting Damaged Valve Lifter by Old boy currently on page 3. On my bike the rivets on the ACR are so loose I believe the actuator part of the release is contacting the follower as it spins. The spring is in perfect conditon.The cam was also slightly marred but rubbing compound removed that. I'll be removing the release as it's shot any way.There's way more experience than I have on this forum but there are probably more than a few bikes running around with just the spring removed and I can't believe my bike(now Oldboy's as wel) is the only one to develop this problem. Thoughts... Stay safe!
 
  #1076  
Old 04-09-2020, 05:29 PM
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Please post pics of your KACR showing the loose rivets..
 
  #1077  
Old 04-10-2020, 12:54 PM
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Thumbs up ACR photos

OK Here goes, In the first pic the mechanism has been propped open with a little bit of rubber line (just visible on right) and the lever (part that actually contacts the follower) appears to be about where it should be when running. In the second I've propped it laterally with a bit of cardboard to show how much deflection there is and what "might" be happening once cam is revving at say 3000-4000 revs? The only indication of this are the circular markings on the follower,which seem to be made by the very tip tip of the lever. For the record, I'm the second owner but have never ridden it ,bike has around 880 miles,and valve clearances were good although the feeler gauge was a little sticky going under that particular lobe but marks on follower explained that.As suggested two other pics show up in gallery and Oldboys post (still on page 3 of main thread list) has a photo of what appears to be similiar problem.Hope this helps.

 
  #1078  
Old 04-10-2020, 01:47 PM
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Hi Klxster Tried to post a couple of pics but once again got the moderator will review message, have to work on that.However the photos appeared almost instantly in gallery and assuming you see the same sequence there are now 4 pics that I tried to post on this thread.Don't know where the accompaning text goes so, pic#1 is of mechanism propped open as where it "might "be when running and #2 shows where it "could"go,free play allowing, when spinning at say 3000-4000 revs (cam speed).It appears the "lever",the part that actually touches cam,is very close to the follower and on this engine has almost certainly touched it.See circular marring.Oldboy's post on Page 3 of main forum menu seems to point to a similiar problem.If anyone has sugestion on what I'm missing in trying to post pics I'd appreciate it.Hope this helps
 
  #1079  
Old 04-12-2020, 07:32 PM
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I just did the Intake part of the MCM on my 2019... Soooooo happy I did. I went from moped to motorcycle with two hours labor!
Thanks for the thread.
 
  #1080  
Old 04-12-2020, 08:08 PM
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Add in the exhaust cam retime to get the "extra torque" aspect of the MCM power enhancement.

Better yet, put your bike on a dyno for power and AFR charts - so we can add "1/2 MCM" power levels to our knowledge base.
 


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