CFM Performance Exhaust Flange - My Thoughts

[nouseforaname90]

Well I figured that most of you have seen the "CFM Performance Exhaust Flanges" on eBay for '85 and newer TRX and ATC 250R's but you didn't know whether it was a good purchase or not. Well.. it is. Here is what I am talking about:
http://cgi.ebay.com/ebaymotors/ws/eB...RK%3AMEWN%3AIT

I decided that ANYTHING would be better than my old, gooey, leaky (VERY!!) stock flange, so I took a chance and got it. Once I recieved it in the mail, I was like, "What the hell? This tiny thing is $50?". Well today I got around to putting it on my R, and installing it is a snap! My old flange was very loose on the pipe and probably a few mm from fitting properly. Once I put this one on, it sealed VERY tight and now my machine is surprisingly quieter (because there is no gap between the exhaust and the flange for anything to get out), and it is no longer smoking or leaking oil out of around the flange. Here is a comparison for you (the old flange also leaked a bit because the o-ring was dryrotted and I didn't know it, but it wouldn't have even came close to sealing tight even if the o-ring was on there):
http://s2.supload.com/free/100_2404.JPG/view/
There is atleast a 2 or 3 mm difference between the sizes of the flanges.

Now.. onto the test ride.
As soon as I hopped on the bike and got going, I noticed how much quieter it is now because of the awesome seal between the flange and exhaust..=better performance. There isn't really much I can say about the test ride except that this flange is awesome. You don't think that the seal between the flange and exhaust would do much, but it did. If you have an old stock flange and you upgrade to a flange like this, it makes so much difference that you need to rejet. As soon as I put that flange on there, it started breaking up between 1/4 and 1/2 throttle and it felt very weak in power. That means that I need to rejet and jet UP, which means more fuel will be able to go into the cylinder, which means I'm going to be getting more power.
I haven't had the chance to rejet yet, but I'll see what I can do. But if this flange makes so much of a difference that you have to rejet when you install it, I say that is proof enough that it works well. I recommend this flange to anyone with a watercooled R!!
Ben

[ChrisD]

I don't have the CFM brand, but I also bought a double ringed, billet flange and it is awsome. No more leaks. I highly recommend them as well.

The exhaust flange is on of the chronic problems on the R.

When I rebuilt my R, I did not buiild it to stock. I rebuilt it to fix all the Honda problems "from the day" and the exhaust flange is definitely one of them.

[Fox250R]

Thats what i use as well.....love it

[nouseforaname90]

Was it you that made a post about these flanges before, Fox? I remember seeing someone else post about them before, but I couldn't find the post/poster..

[Fox250R]

I think i asked about it a while ago..I was shocked it was only 34 dollers.. its like 44 now, but when i was getting mine i asked if anybody else used them and how they liked it..34 bucks just seems kinda cheap but it works awesome to this day...

[Dammit!]

Was it you that made a post about these flanges before, Fox? I remember seeing someone else post about them before, but I couldn't find the post/poster..

Might have been me. I installed one a while back (not cfm). I think mine is actually an ESR or it looks just like it anyway. Real nice and I agree with your post. Must have item in my opinion.

[85 250sx]

I bought a slightly used ESR like one off ebay for like 25 and when it came in the mail i remember thinking that i had wasted my money. But after i installed it the leaking and smoking completely stoped. Deffinitly worth every penny.

[deathman53]

I'm told they also fit air-cooled 250r's too

[250rAL]

My stock flange doesn't have an O ring, it has a split metal ring. It's like a thick piston ring. Did the '86's have the O ring?

[ScottZJ]

Yeah I will most likely be getting one for my new R project. I was looking at the trinity ones too on ebay.

http://cgi.ebay.com/ebaymotors/Trini...spagenameZWDVW

[Dammit!]

Does anyone know of one of these flanges that will fit a Tri-Z?

[dovesprings250R]

Love the esr flange on my R. A must have.

[slothminx]

Tri-Z's use a different system to the R, the Flange is part of the cylinder.

Best idea Ive come up with is a silicon tube that can be slid over the flange on the cylinder that will seal up to the pipe.

[Dammit!]

Tri-Z's use a different system to the R, the Flange is part of the cylinder.

Best idea Ive come up with is a silicon tube that can be slid over the flange on the cylinder that will seal up to the pipe.

I didn't realize that. I haven't torn my Z down yet (obviously, lol).

What about some of the YZ cylinders that swap onto the Z?

[nouseforaname90]

My stock flange doesn't have an O ring, it has a split metal ring. It's like a thick piston ring. Did the '86's have the O ring?

Reeeally? Hmm. Well then I guess the flange on my R was aftermarket? It had an O-ring and the groove around the flange was definately for an o-ring. Hmm. Oh well.. this new one looks better, fits better, and works better.

And .. I'm pretty sure they are all one piece.