Ok folks, riddle me this....
One of our machines is MUCH louder than the other one; all engine noise, comes straight from RPM's, I'm not sure if I have an exhaust leak somewhere that's real bad or if the engine itself is making this racket. Not grinding or anything, just super loud, sounds like a chainsaw or something, in the midranges it's especially annoying, pretty uncomfortable, actually.

I looked at what I could see of the exhaust system, didn't see anything bad off, but if this isn't some kind of intake or exhaust issue, the next thing (I'm thinking?) is valve adjustment? If not that, than what, probably engine? Machine has about 1100 miles on it, runs like a top, gets the same MPG's as the other one, oil's clean, just changed....I don't want to have to wear ear plugs so fill in the blanks here, would ya Fellas....?   

They do have a issue or weak springs I know mine and nmkawi did I went to the local hardware store and bought some short strong springs and changed them factory ones out, check that also I know the values were out of spec but not to the point were they were makeing noise like yours but you might want to check them I think that somewhere on here nmkawi posted specs.

I wonder if it is the springs, Jogon. They look fine, but I'm telling you it's crazy how much louder that engine is than the other one, it's like you can hear one of the cylinders hitting, (running) and it howls. Did you guys replace all the springs or just some of them? Any particular type of spring I need?

I'll post a pic of the springs I used but were I was haveing issues was on top part of header big time leak and a lot of noise i will post pic tomorrow.

Valves with too much lash will tick pretty good. I'm going with loose exhaust joint too.

Cosmos, I agree, I don't think it's valves (although it's possible) but they're not ticking, like you hear in a car engine, when the valves are done, it's more like you can hear one or both of the cylinders, and you hear it most when the engine is under some pressure like when climbing a gradient, just going uphill. It howls though, it's loud....

You sure it's not comeing from the clutch cover area ?

if it is exhaust, the joint where the muffler attaches to the intermediate pipe can get tweaked out of alignment causing a leak at the joint, can usually be remedied by "twisting" the muffler back into alignment (the muffler is rubber mounted). As others have mentioned, the root cause is usually springs that have become weak.

typically the exhaust joint where the muffler meets the Y-pipe gives. IF this is the case, replace the srpings with shorter, thicker gauge springs. We use Polaris snowmobile exhaust springs. Also, dont reuse the exhaust doughnut as once they are exposed to the exhaust they are ruined.

emersonsc, it's great to have you back around here posting these tips. I can't even begin to think where we'd be without the helpful posts and how-tos from our select CF Moto experts and dealers. It is very much appreciated, and I do hope that things improve on the corporate to dealer end of things for you.

I also 100% agree with your other post on how poorly a job CF Moto corporate in China has done to promote their brand here in the US. Until the budget for CF Moto US is increased and they allow the US entity to properly market the product, they won't make the inroads that they could have. I like the ideas that were mentioned in CFmotoguy's thread (http://cfmoto-forum.com/introduce-yourself-and-your-ride/greetings-from-the-mothership!/msg8385/#msg8385), so here's hoping we see some brand recognition to help us out.

We have 3 800 z force 53 machines and 2 of them developed an exhaust leak at the joint right away. Easy fix. My problem is one is a year old with 200km on it and the differential noise is much louder it seems than the other 2.

The exhaust springs are not up to the job, on mine if I blipped the gas pedal the joints would open up, I had one conical seal fail completely so new springs and a new seal have been fitted, no more leaking exhaust'

The diff may need re-shimming and a bearing check, one of the bearings in mine was very rough.

The springs I used on mine were 75mm from a motocross bike.

[2015 Z Force 800 53/Trail EPS]

Looks like the Moose springs I had to put on mine for the same reason. I have a write-up in the How To section as well. Yeah I pulled the front O2 sensor and installed a low pressure gauge to see what it had and when you nailed it to would show slightly over 4psi. I'm one that's used to see pressure in the ounces, not pounds but as I understand it, its not that unusual for V-twins to have that kind of back pressure. Doing my exhaust mod cut it in half. That and the springs stopped the joints form unseating. I also found I could cut a loop off the stock springs and re-curl the end to make them tighter. Did that on the ones off the front cylinder. The rest got the Moose springs.