Rev pipe and a DEK, couple of questions.

grump99 · Post by **grump99** » 09:59 am Jul 22 2007

Hello,

I currently running my '04 200 with following setup:

Fmf woods
Stock Silencer
RB Carb mod
DF3 reed cage
150/40 CEK-3

I ride a good mix of single track and wide-open terrain. I have the jetting dialed in pretty good with the above set-up. I find that the CEK hits a little to hard too soon. I am also looking for a little more oomph on top for wide open riding (seems to sign off fairly quick).

I don't want to loose much low end grunt. I am looking for a nice and smooth (and torquey) low-mid with some more oomph on top. It seems that a rev pipe and a DEK would be the way to accomplish this? It would seem that the DEK would smooth things out and the rev would give me more on top. Would I lose a lot of low-end with this setup? What would be a good starting point for summer jetting?

Any opinions/advice are appreciated.

2001kdx · Post by **2001kdx** » 10:21 am Jul 22 2007

I don't have actual experience with the woods pipe, but I do really like my setup, which is Rev pipe with DEL (no RB work)

It makes decent low, good mid and even better high-mid to top. It pulls smoothly and I believe it's way better than the C taper set up in every way. The DEL gives more low, less mid (smooth) and more up top to rev it out.

IMO if you're a good enough rider, the bottom end loss won't annoy you. I have learned to ride this bike above the kips opening to get the full effect of the pipey feel of this setup. Good luck

Post by **Indawoods** » 10:23 am Jul 22 2007

Sounds like your on the right track.... I love the DEK... smooth is all I can say but up top she's a banshee.... I am still running my woods pipe and don't have any issue with topend performance.

The jetting depends on your idea of summer jetting. Some folk's winters are others summers. Even humidity plays a role....

grump99 · Post by **grump99** » 06:54 pm Jul 22 2007

Yeah I think I'm gonna try the DEK 1st, then the pipe. Thanks for the info!

TWMOODY · Post by **TWMOODY** » 02:25 pm Jul 25 2007

Fmf woods
Stock Silencer
RB Carb mod
DF3 reed cage
150/40 CEK-3

Grump
your jetting seems a bit skinny, done a plug chop?
is your altutide around 700ft?

I would suggest trying a DEK at #4 first then #3
See what works better.
I have found #4 better on my setup.

EDIT- skinny on the main I mean

canyncarvr · Post by **canyncarvr** » 05:13 pm Jul 25 2007

You know this already...but...

The -35 pipe doesn't have the runout on top that the -30 does.

With a modified carb and a DF3 reed setup, there is no reason you can't use a -30 for the 'yeehaw' side of things..and be perfectly happy with the bottom end of things at the same time.

Jetting 'by mail' doesn't work. That said, your setup with a -35 pipe should be quite close if not just fine. The -35 runs 'richer' than the -30 does. I've changed from a -30 jetted well to a -35 and NOT changed jetting..and fouled a plug.

What CSS do you run?

I would suspect the difference with just the needle change won't be huge in the upper RPM ranges...your -35 is seeing to that.

A repeat...but I used to change from -30 to -35 on a regular basis depending on where I was riding. With the RB carb and DF3, I found the -30 to work fine everywhere.

I'm not talking about 'settling' for a lesser response anywhere...I mean it's perfect everywhere.

Noooo...I don't have the bottom end of a CRF400X..and I don't have the topend of a CR125, either. Given a woods bike (the KDX) and 198cc displacement..it runs 'perfectly' bottom to top.

The jetting you list with a -30 will be close..probably better, I'd guess. With a DEK needle, you may find a 152 is preferable.

grump99 · Post by **grump99** » 04:09 am Jul 26 2007

Thanks for the input. I run 12-47 gearing. I went for a ride yesterday and realized that I'm not good enough to need more top end power. Instead of the pipe, I'm going to buy a good set of hand-guards and some better protective gear.

I'm gonna try the DEK for now (its on order). I am interested in a more linear throttle response. I think the DEK will work for that. Will I need to change my main/pilot when I switch to the DEK?

canyncarvr · Post by **canyncarvr** » 11:01 am Jul 26 2007

Re: Will I need to change my main/pilot when I switch to the DEK?

If it was right before from idle to 3/4 throttle, it should be right, still with the DEK.

'Jet By Mail' (again) being mostly a waste of time, I'd try a 148 with a -35.

The DEK will indeed give you better (in the way of linear) throttle response.

If you have the opportunity to try a -30, it would be worth the trouble of changing the pipe to try it. You may find an overall improvement that you didn't expect.

..that just more anecdotal (and therefore mostly useless) information..

TWMOODY · Post by **TWMOODY** » 12:34 pm Jul 26 2007

'Jet By Mail' (again) being mostly a waste of time

CC what is your definition of "jetting by mail" ?

They send it by UPS or fedex ??

canyncarvr · Post by **canyncarvr** » 12:43 pm Jul 26 2007

Pony Espresso

TWMOODY · Post by **TWMOODY** » 01:26 pm Jul 26 2007

The -35 runs 'richer' than the -30 does. I've changed from a -30 jetted well to a -35 and NOT changed jetting..and fouled a plug.

You saying the -30 rev pipe needs more fuel than the -35 woods ?

I have a woods pipe I am going to throw on just to see how i like it.

canyncarvr · Post by **canyncarvr** » 01:42 pm Jul 26 2007

You saying the -30 rev pipe needs more fuel than the -35 woods ?

No.

It's a matter of air flow, and pressure differential.

When you change the airbox to a less restrictive state, the jetting generally goes 'up' (bigger numbers). That's not because a freebreathing airbox makes the engine need more fuel, but because the carb signals change...due to pressure differential changes.

I'm saying a -30 takes bigger jets than the -35 does.

Well, mine did. That was before a lot of things...before a modified carb, before a good reed system.

TWMOODY · Post by **TWMOODY** » 01:54 pm Jul 26 2007

canyncarvr wrote:You saying the -30 rev pipe needs more fuel than the -35 woods ?

No.

It's a matter of air flow, and pressure differential.

When you change the airbox to a less restrictive state, the jetting generally goes 'up' (bigger numbers). That's not because a freebreathing airbox makes the engine need more fuel, but because the carb signals change...due to pressure differential changes.

I'm saying a -30 takes bigger jets than the -35 does.Well, mine did. That was before a lot of things...before a modified carb, before a good reed system.

You said no to no more fuel on an -30 butttttttttt
Larger jets without changing the intake side = MORE FUEL in
my neck of the woods.

canyncarvr · Post by **canyncarvr** » 02:15 pm Jul 26 2007

Re: 'You saying the -30 rev pipe needs more fuel than the -35 woods ?'

I understand that 'understanding'.

I also understand the way it works. To pick at it is of no value and unlikely leads to any enlightenment.

canyncarvr · Post by **canyncarvr** » 02:21 pm Jul 26 2007

I can't stand it........

This is not correct metaphorically, but does show the point.

Apply 2" of suck to a 1/2" straw (given liquid at a given temperature, air pressure and lift). Get 'a' volume.

Apply 2" of suck to a 1" straw (all the givens the same) and you will get 2 x 'a' volume.

But...apply 1" of suck to that 1" straw..and you won't get as much as you did with the 2"...even though the 'jet' (straw) is bigger.

TWMOODY · Post by **TWMOODY** » 02:51 pm Jul 26 2007

CC
Certainly I am not picking, just trying to understand your theory.

With the two pipes on the identical setup:

If you were to measure MAF through the carb at say 5000 under a load
with each pipe would they be the same. (Guestimate 3gps)

If you were to measure MAF at the tail pipe (same conditions)
would the number be the same.

Inlet size and outlet size on the pipes being the same, the frequency
in the pipe is changed by size and length thus changing the torque curve.

Does one pipe flow faster than the other ?
Woods pipe more restricted?

EDIT @5000rpm it would be 4.40 GPS

Post by **Indawoods** » 03:07 pm Jul 26 2007

No ...they are exactly the SAME!!!!!!!!!!!!!!!!!!!!!!!!!!

canyncarvr · Post by **canyncarvr** » 04:29 pm Jul 26 2007

Sorry...it wasn't a reference to you picking...but my picking. Take no umbrage, please.

I don't know the flow numbers. I know I found the -30 took a richer jet-set than the -35.

While the 'therefore the -30 uses more fuel' is a short step to make, I don't think it's a step in the right direction.

Do I have any specific data to back that up? No. It seems to me (wow..that's shaky!) it relates perfectly with the aforementioned bigger jets and modified airbox idea..and that DOES have specific data to back it up...my arse on the seat!

Re: 'If you were to measure MAF at the tail pipe (same conditions)
would the number be the same.'???

I very much doubt it. I'd say I'm absolutely sure they wouldn't be...but that would kind'a shine a light on my pig-headed obstinate ignorance of the matter...and we can't have that!

2001kdx · Post by **2001kdx** » 04:54 pm Jul 26 2007

I'm with foots on this one

I also think carvr should explain to me what 'jet by mail' means.

If you get junk mail on tuesday, do you jet rich?

TWMOODY · Post by **TWMOODY** » 05:03 pm Jul 26 2007

Take no umbrage, please.
None here CC !!!

I have extensive background in driveability/computer/engine performance
on cars fuel inject and non with 4 gas analysis and try to get detailed
explanations to convert to the 2 smoker side of things.
My bike runs and rides (IMO) pretty excellent but that because of
some of the excellent posts from yourslf and many others on this site.

Time for a beer

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Rev pipe and a DEK, couple of questions.

Rev pipe and a DEK, couple of questions.