525 EXC exhaust

The can on my 06 525 exc looked horrible (scratched and tarnished) and the end cap had been modified and sparky removed.  Created quite the "tumble" effect in the end section of the can.  Had plenty of bottom end but would not rev out at all. Just went flat on the big end.  I already jetted it up which helped some but still wouldn't even get close to approaching the rev limiter.  Not that I want to bounce off the limiter but when I tried to open it up on the straights, I had to short shift it to keep it climbing in speed.

So on a whim (couldn't find hard proof), I picked up a 2012 450 sx-f can off of flea bay for cheap with free shipping.  I msg the seller and got some "rough" dimensions but I lucked out.  It bolted right up.  Fit tighter on the header pipe than the factory can but I'm guessing the original was just whooped from being so old.  Bike will pull the to the limiter no problem now and never goes flat on top.  Very quiet idle and cruise but if I get into the throttle aggressively under load, its quite a bit louder but not obnoxious loud.  Just need to add a sparky and I'm all set.  Just an FYI for others out there with older EXC that don't want to drop a lotta cash on a slip on.  I payed $80 free shipping.

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Any weight difference?

I did not weight it, but it did feel maybe half # or slightly more lighter.  I rode some very tight single track this weekend with a few areas that open up, and its much better than the stock can.  It is louder, but I can keep it in 2nd on all the tight stuff and 3rd once in a while till it opens up.  Unless there is a very steep uphill that I have to "tractor" up, 1st gear is not needed.  13-50 sprocket setup.  I may go to a 14T front though as I felt like I could use more "lug" in 2nd gear on the tights.

I like this.

Any jetting change required?

 

When I got the bike, it was jetted for high elevation (Colorado) but I did not know that.  It had the CO ohv sticker on the forks but bike was from OKC.  Had a 175 in it.  I noticed it would get hot and fan would come on very often.  Once I found the jet was so small, I put a 178 in it.  helped a lot but still would not rev out like expected.  I put a 180 in it and was even better.  Then swapped the can over to the SX-F one and now it revs clean all the way to 9500.  I don't typically wind it out like that but when traction gets low it happens lol.  The plug looks like its burning properly, light tan/grey on the electrode and nice burn ring 3/4 around on the last thread.  Ground strap has burn mark at the bend so seems to be spot on.  Fan only comes on when I'm in the super tight bark buster smacking tree kinda stuff and not on for long.  My vapor said 205 was max temp reached from last Saturday. 

I didn't want to buy a super expensive FMF/yoshi type slip on, and the factory header pipe seems to be good enough.  Swapping the the SXF can did make a very noticeable difference "seat of the pants" feel.  I'm happy with it and it has more power than I need now.  The transition from idle to midrange is much smoother so makes for an "XR" type of cruise.  There is more low end grunt, but its very linear so predictable which is a good thing IMO.

Now I just need a more comfy seat lol

You getting any back tire rub on the inside of the pipe?  If I run a 120 it rubs, 110 it's fine.  I run a Lexx pipe.  Good to know on the SX-F pipe.

No but its close. A 120 was on the bike when i got it and it rubbed bad on the stock can. I have a 110 on it now. Im going to get a 907HP tire as they are a tad narrower then a lot of 120s on the side lugs. I had my old can shimmed prior to this can with .250" aluminum spacers. If my 120 rubs later ill shim it up again

Any decel pop with this setup? Mine pops bad on decel. I have heard its from the header pipe not sitting correctly so might not make a change. But my can is pretty beat scratched dinged. Pretty sure their is no packing to speak of left as well. Sounds like a good setup. 

Edited by Bobatsea

My 05 was popping bad as well when I acquired it.  I attribute that to lean jetting and air leaks where the exhaust flange and header pipe meet.  You can seal it up with high temp RTV, doesn't last long though. Some guys have cleaned up the mating surface with a dremel tool which is a a long term fix.  Once i got my jetting correct and the muffler packed correctly I hardly notice any decal popping.

I have an 04 525 EXC which I recently bought for 2k.  It is in great shape and only has 160 hours on it according to the computer. It has a similar problem with not making revs.  I looked into the jetting (here at sea level need a big one!) and it seems fine.  Maybe this is the fix I need.  Someone told me on the earlier engines the valves might need adjusting and they are different than the later models.  Not sure what years have those changes but apparently mine is the before version.  The guy i bought it from said that adjustment was checked a couple of months before he sold it to me and he had barely even started the bike since then so he could not imagine that being an issue.  It sits high for a bike thankfully for me as I am 250lbs at 6'8" so maybe a bit large for this bike.  The rear tire does rub on the inside as well, I was wondering what to do - slightly thinner tire might do the trick and never thought about spacers, but I'll look to see if I can to that as well.  The other thing about this bike is it is hard to start when cold.  no way I can use the electric start, the battery dies in a couple of minutes (it is new!) and I have to kick start it.  I heard there is a big battery kit available - I might want to look into that as well.

My 360SX is difficult to start too but that bike is crazy fast!

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2 hours ago, curtmixon said:

I have an 04 525 EXC which I recently bought for 2k.  It is in great shape and only has 160 hours on it according to the computer. It has a similar problem with not making revs.  I looked into the jetting (here at sea level need a big one!) and it seems fine.  Maybe this is the fix I need.  Someone told me on the earlier engines the valves might need adjusting and they are different than the later models.  Not sure what years have those changes but apparently mine is the before version.  The guy i bought it from said that adjustment was checked a couple of months before he sold it to me and he had barely even started the bike since then so he could not imagine that being an issue.  It sits high for a bike thankfully for me as I am 250lbs at 6'8" so maybe a bit large for this bike.  The rear tire does rub on the inside as well, I was wondering what to do - slightly thinner tire might do the trick and never thought about spacers, but I'll look to see if I can to that as well.  The other thing about this bike is it is hard to start when cold.  no way I can use the electric start, the battery dies in a couple of minutes (it is new!) and I have to kick start it.  I heard there is a big battery kit available - I might want to look into that as well.

Welcome to TT Curt,

I have the '05 version of your bike.  The stock intake valves on that bike are known for being soft and require frequent adjustment.  The symptom on my bike when the valves needed adjusting was hard starting when cold.  As I put more hours on the bike it started burning oil.

Don't use the book method for valve adjustment.  The best method is known as the 1/6th turn method.  It's super easy to do and yields great results. Check out this video.  It's old and looks like it was recorded with a potato but the content is stellar.  The dude in the video is Travis of Thumper Racing in Gardnerville, NV.  He is one of the best RFS engine builders in the US and quite active on KTMTalk.

After roughly 350 hours on the clock, I sent off the head and cylinder off to DJH.  One of the things he did was install +1 Kibblewhite valves in my engine.  My bike occasionally sits for a couple months but will start first or second kick even then.  Now I'm not sure why I even check my valves as they never move and my oil consumption is near zero.

A properly tuned bike will not need to run the starter for two minutes so it's better to address the tune than get a bigger battery.

 

Where in California are you?

Awesome.  thanks for the info.  I'll check it out.  I am in Encinitas.  

Only popping it does is when its cold and I goose it.  Ive pulled the header pipe previously and put a nice bead of high temp rtv on the flange outlets, let the pipe back on, wiped off excess and let it dry overnight.  No leaks at all and have 40+hrs on it now since I sealed it. 

When my bike did decel pop really bad, it was because it was overly rich on the bottom.  Once the mix screw is adjusted when motor is in the 170s temp wise, leave screw alone.  Mine runs 180-190 just about all the time so thats where I set the mix screw for the most consistent idle.  Cold It wants the choke longer this way and I have to idle it up for a minute or two but once its hot I run the idle speed back down and it purrs like a kitten with no popping, no hesitation on throttle snap, and of course...no damn popping.

Put 60miles on it this weekend at the beach and ran great  Max speed of 78mph on sand and shell shoals.

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