What have I done

I have a 2012 rmz 450 with 110 hours on it. Fresh rebuild 7 hours ago top and bottom. Went Cp carillio rod and high comp piston and new oem valves.

Any way I have just repacked my oem exhaust with lexx exhaust packing, oem mesh. I did cut the 25mm cone off the end of the factory insert. It seems like its running very lean now. I'm using the rich coupler. The muffler is getting really hot, and makes a tink tink noise when you turn the bike946912_396986330405863_727870115_n.jpg off.


What have I done?

When you put in the new valves did you have the seats cut? Were you running the HC Piston before? You might need a tuner to richen it up more that what the couple can do! Do you notice it riding the bike that it's running lean? In what part of the powerband?

Yeah I have had the seats recut. Seems to run ok, I'm just a bit concerned about how hot the muffler is getting since the repack. I used lexx premium mat and I'm thinking maybe that I haven't packed the muffler properly. May be I haven't got enough packing down in the beginning of the can and maybe that's causing a build up of hot gas down there. Do you think this makes sense? 

I wouldn't worry too much about it. You could repack if you really feel you need to. As the new packing breaks down it will allow that gas to get out easier. Just watch that it doesn't melt your air box. 


Just my .02

Vince- Try repacking and see what happens. Do you have any packing material left? Just add it.


After 110 hrs. how'd things look?

I've ordered some new packing. Cheaper than a new air box. At 100 hours of hare scramble trail riding and mx every thing looked fairly good. I did new valves as I had left the air boot loose at one stage and sucked abit of dirt in, the inlet valves tightened up abit so I did them and a seat cut for good measure. Crank pin was just showing alittle scuffing but every thing looked fairly good. I did mains, big end genuine and cp rod and piston. Clutch was sweet. Polished my clutch actuator and rod and extended the actuator and along my zeta cp clutch perch the clutch is lighter than any hydraulic unit. I use total full syn 10w50 oil and I do oil and filter every 5 hours.

Did you finally solve the issue?

Have you clean your fuelpump? Injector might be clogged or like in mine -09 fuel hose was crumpled. Bike ran lean and didint idle.

Did you finally solve the issue?

once again, have you solved the issue?

Haven't had a look yet. Tomorrow I'll pull apart and repack the muffler and maybe get out for a ride. I did a ultra sonic clean on the injector when I did the rebuild.

So I pulled the muffler apart and looks like I was right. Not a case of it running lean but instead a case of me not packing it correctly. Ive tried to add some photos but what was happening exhaust gases were catch at the start of the muffler and making it get extremely hot. Its stuffed the packing. This time I have used DEP loose packing, done the base real good first, then put the can back on and packed it the slow but methodical way. Now just have to sort my front brake, hit a marker peg with the lever and blew the master cylinder seals last time out, have replaced them with a all balls kit but the brake feels crap, have bled them every which way, I'm certain its just a shit kit. If you pull the lever real fast with the cap off you can see fluid come back into the master cylinder. I've never had any luck with any all balls product.


















Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now