'06 pipe on an '08

[swaldrop]

I just replaced my '08 exhaust with a full system from an '06 that I got off Ebay. Wow. I am still in disbelief as to just how much more low end was achieved, but I'm sure you have all heard that enough... Although this new found low end is great (if not scary at the moment), it seems as though it may have came at a price. I may be nuts, but the bike doesn't seem like it wants to rev out like it did before. I have listed the possible reasons below...

Reason #1 - I'm crazy: My initial thought is that it just 'feels' like there's less on top because I am getting there so much quicker. Could it be that now that the bike is SO MUCH stronger on bottom that the top feels comparatively weak?

Reason #2 - New head pipe: The '06 head pipe is not consistently round. About an inch or two after it exits the motor it flattens out quite a bit and becomes oval, with the flatter part being parallel to the ground. Then, as it starts to make the bend back, it flattens out the other way. I have never bent tubing before and I am sure there is some flattening that occurs, but this is really noticeable. It especially seems odd as it comes out of the motor as it hasn't even starting bending yet. See the pics below. The measurements shown are conversely similar with each other, where the narrow part on each measures about 36mm and the wider about 51mm. Is this normal?

Reason #3 - Jetting: No idea here. To me, the bike runs great, albeit a little weak on top (maybe). I have no idea where to start or even if it's required. Anyone in the central Florida area who has done the same thing and has a good base? Seems to me the stock jetting is a 'good base' but again, I'm clueless when it comes to jetting.

Long post, but any help is appreciated.

[KJ790]

All of those are possible. The only thing that you can really change and see if it helps would be jetting. A main jet that is a little rich will often make the top end feel dead without making the engine seem like it is running poorly. You can try dropping the main down a little and see how it runs.

[swaldrop]

All of those are possible. The only thing that you can really change and see if it helps would be jetting. A main jet that is a little rich will often make the top end feel dead without making the engine seem like it is running poorly. You can try dropping the main down a little and see how it runs.

Does that pipe look odd to you?

[KJ790]

Does that pipe look odd to you?

I think the stock header on the 06 was kinda flattened out, but I'm not sure. I'll dig out my stock 06 header tomorrow and look at it.

[swaldrop]

I think the stock header on the 06 was kinda flattened out, but I'm not sure. I'll dig out my stock 06 header tomorrow and look at it.

Thanks. If it's normal, then that would be cool.

[grayracer513]

The '06 head pipe is not consistently round. ... Is this normal?

Yes. At least according to both of mine.

As long as there are no sudden changes in shape or cross sectional area, that won't really affect power output. More probably, it relates to the increase in overall length, and to jetting. If I had to guess without seeing or hearing it, I'd guess it was rich, but you can safely go two steps in either direction with the main from where it currently is, and the results should tell you.

[swaldrop]

Yes. At least according to both of mine.

As long as there are no sudden changes in shape or cross sectional area, that won't really affect power output. More probably, it relates to the increase in overall length, and to jetting. If I had to guess without seeing or hearing it, I'd guess it was rich, but you can safely go two steps in either direction with the main from where it currently is, and the results should tell you.

That makes me feel better about the pipe.

I suppose it wouldn't hurt to get a few jets and start playing around with it to see if I can get the top to properly compliment the bottom. With the added bottom, I'm sure I could just simply short shift and be fine. As it is, the thing feels almost like an automatic. Just leave it in 3rd and run it.

I also could go back to a stock sprocket to get more out of third. I had put a 50 on it due to the lack of low, but now it may be a little overkill.

[KJ790]

Alright, I just found my old stock header and it is also kinda oval like that, it is supposed to be that way.

[swaldrop]

Alright, I just found my old stock header and it is also kinda oval like that, it is supposed to be that way.

Cool. Thanks for looking. Now I'm either just nuts or the jetting needs a little help

[grayracer513]

Oh, you're nuts, alright, but that doesn't mean you don't have a jetting issue. ?

[swaldrop]

Although I still have not yet messed with any jets, the bike felt much better today. That being said, I am still not sure I like the power.

The one thing about the bike with the stock exhaust was the fact that it was butter smooth and super linear. The power was always super easy to use, it just didn't have enough of it. Now the bike hits extremely hard (comparatively speaking) off idle then kind of tapers off from there.

Again, I have to play with the jetting still and I also plan on going back to the stock 48 or maybe just a 49 rear sprocket. I have been running a 50 and feel it may be too much. I'm confident that with some more work I'll get it to work great. I'm just venting.

Oh yeah, and I'm pretty sure that ridding my buddies '08 CRF450R today was a bad idea. That thing was really, really good and trust me when I say that I didn't want it to be nor did I expect it to be. ?

[erickdj]

Although I still have not yet messed with any jets, the bike felt much better today. That being said, I am still not sure I like the power.

The one thing about the bike with the stock exhaust was the fact that it was butter smooth and super linear. The power was always super easy to use, it just didn't have enough of it. Now the bike hits extremely hard (comparatively speaking) off idle then kind of tapers off from there.

Again, I have to play with the jetting still and I also plan on going back to the stock 48 or maybe just a 49 rear sprocket. I have been running a 50 and feel it may be too much. I'm confident that with some more work I'll get it to work great. I'm just venting.

Oh yeah, and I'm pretty sure that ridding my buddies '08 CRF450R today was a bad idea. That thing was really, really good and trust me when I say that I didn't want it to be nor did I expect it to be. ?

play with your jetting a little more, the power shouldn't taper off like that. I know my bike doesn't taper off after a while, it keeps pulling like a monster all the way to the top.

don't worry about the honda, after you get yours all tuned properly it will totally make you forget that the honda even exists.

[Beaz]

Although I still have not yet messed with any jets, the bike felt much better today. That being said, I am still not sure I like the power.

The one thing about the bike with the stock exhaust was the fact that it was butter smooth and super linear. The power was always super easy to use, it just didn't have enough of it. Now the bike hits extremely hard (comparatively speaking) off idle then kind of tapers off from there.

Again, I have to play with the jetting still and I also plan on going back to the stock 48 or maybe just a 49 rear sprocket. I have been running a 50 and feel it may be too much. I'm confident that with some more work I'll get it to work great. I'm just venting.

Oh yeah, and I'm pretty sure that ridding my buddies '08 CRF450R today was a bad idea. That thing was really, really good and trust me when I say that I didn't want it to be nor did I expect it to be. ?

I think the stock sprocket was a 49 on the 08

As i have a 50 on mine

On another note do you have to use the full 06 system or would just the slip on work:confused:

[swaldrop]

I think the stock sprocket was a 49 on the 08

As i have a 50 on mine

On another note do you have to use the full 06 system or would just the slip on work:confused:

Stock on the '08 was a 48. 49 on the '07.

As far as the exhaust goes, you have to use the full '06 system. The head pipe diameter on the '08 is too large for the '06 silencer to slip on.

[krackhead]

Stock on the '08 was a 48. 49 on the '07.

As far as the exhaust goes, you have to use the full '06 system. The head pipe diameter on the '08 is too large for the '06 silencer to slip on.

do you have your 06 bike laying around? I am really curious to know if the 06 stock header will even bolt up to the 08 head. I am convinced it wont since its larger diamater, but others disagree.

[Beaz]

My 08 has a 49

The manual says 49 as well o well

but thanks for the info on the pipe

ill be looking

[swaldrop]

do you have your 06 bike laying around? I am really curious to know if the 06 stock header will even bolt up to the 08 head. I am convinced it wont since its larger diamater, but others disagree.

I didn't have an '06, but I do have an '06 complete exhaust on my '08. Fits great. The exhaust port is the same size on all '06 through '08.

[swaldrop]

My 08 has a 49

The manual says 49 as well o well

but thanks for the info on the pipe

ill be looking

That's weird. Mine came with a 48. I always wondered why too, as the bike had less power (due to the silencer of course) than the '07 yet the '07 came with a 49. Maybe they delivered bikes with both.

[swaldrop]

My 08 has a 49

The manual says 49 as well o well

but thanks for the info on the pipe

ill be looking

One other thing... If you are looking for just a slip on solution then you may want to look for an '07 silencer instead. From what I hear they will fit right up to the '08 header.

[grayracer513]

do you have your 06 bike laying around? I am really curious to know if the 06 stock header will even bolt up to the 08 head. I am convinced it wont since its larger diamater, but others disagree.

DRD makes one exhaust for all '06-'08 models. At least two people on the board have installed '06 systems on their '08's. The same exhaust gasket is listed for the '06-'08 models.

But you can be convinced of anything you might like.

BTW, the headers on all three year models, '06-'08 are a different diameter at the head end then at the outlet end.