RB Carb Mods w/Fredette Porting & Head Mods

Questions and Answers about the best carb and Head mods available for the KDX.
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Post by fuzzy »

Indeeed. I'M saying the head and cyl need to be done at the same time, by the same guy. The head is simple enough to be done by ron when he can assume stock bore, and porting config.
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Post by canyncarvr »

If I may be so bold as to speak as to what someone else is saying...

She's saying the head is going to the same place that is going to work on the cylinder.

The reason I think that's what she's saying is 'cuz she was perfectly clear when she SAID so! :wink:

Certainly the two are better off together. It's not reasonable to expect shop 'A' to know exactly what's going on in shop 'B'.

EG uses USChrome. Not that you asked 'bout that part..but a few folks 'round here cuss USC. Like me. At least the USC shop that worked on my stuff.

FWIW...generally speaking, a head is going to need to be made larger in volume to 'fit' increased displacement. The volume of the head isn't as important as its shape. The º of the dangle, squish, quench..that's what makes a head work.

...or not.

Brought that up only because the word 'cut' kind'a leads to the idea that it's make 'smaller'.


Fuzzy's right about the race gas part. Too many riders have been less than happy with needing to use a better grade fuel than the slop out of the local pump after such modifications. Those that did specify 'pump gas' I mean.

If not a better fuel...an octane booster like toluene may be a choice for 'ya. You can pick that up at paint stores.

Let us know how it all works out!

**edit** Ooops...got snookered by the 'ol 'page two' again. I didn't see Fuzzy's last post.
Last edited by canyncarvr on 08:55 pm Mar 28 2008, edited 1 time in total.

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Post by Ondatrail »

Got it :wink:
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Post by ebeck »

green_passion, opinions on the carb?
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Post by Green Hornet »

Try the Head & Carb 1st. You start messing with the porting & you might end up with something you don;t like. This is a WOODS BIKE...Not a Desert or MX Bike........
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Post by green_passion »

>|<>QBB<
ebeck wrote:green_passion, opinions on the carb?
I'll let you know as soon as I get my head & cylinder back. We shipped it out last week to EG. It's killing me seeing my modded carb on the kitchen counter and I can't test ride it yet. *le sigh* :cry:
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Post by green_passion »

>|<>QBB<
Green Hornet wrote:Try the Head & Carb 1st. You start messing with the porting & you might end up with something you don;t like. This is a WOODS BIKE...Not a Desert or MX Bike........
I would but the cylinder is on the east coast right now. :cry:

One of the reasons why I love my KDX is because of it's versatility. For a rider like me (female, not super a aggressive rider) it works perfect for a wide range of terrain & disciplines. Not just for the woods. IMO to pigeon-hole this bike into one particular discipline, you're limiting yourself and not gaining a full bodied riding experience. We don't have a lot of options to ride woods here but we do have lots of rocks and technical terrain that I wouldn't want any other bike to ride but my KDX. I've ridden a CR250, XR400, 300 XC-W, 450 EXC, TTR-125, TTR-250 and a WR450. Each time I've tried a different bike, I couldn't wait to get back on my KDX because in my opinion it's a happy medium between a two and a four stroke that gives me the diversity that I need without the weight and uncontrollable power.

The only downside is that it's not a speed & jumping machine but at 33, I don't need to wad myself up over a little bit of personal glory. However, I do need a bit more out of the bike and from what I've read from several sources, the mods that I'm having done should give me what I need for my riding style.

I will bleed two-stroke with shades of green until I die. :mrgreen: :partyman:
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Post by canyncarvr »

Please...a cliff's notes version of what you're having done?

Ported to what desired effect? To be tuned to race gas?

Piston from EG? Pro-X or Pro-lite?

I would appreciate very much a good pic of the intake port when you get the thing back. Curious how it compares to this:
Image

Also would like to see a pic of your cylinder bore surface, see how it compares to mine..in my gallery.

Thanks!

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Post by fuzzy »

Dude, is that FRP's work? :roll:
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Post by canyncarvr »

Did you think my opines regarding my 'sperience with FRP coalesced out of the ether?

Remember this?

Image


'Member that cylinder completely blowing out the RH subport drum?

Man...I could go on and on...but I already have........ :neutral:
Last edited by canyncarvr on 01:56 pm Apr 03 2008, edited 2 times in total.

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Post by canyncarvr »

BTW...this is the 'before' intake (don't sweat the particles):

Image


You don't like how it turned out? :hmm:

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Post by fuzzy »

Oh yeah, I remember. Similar pics to compare the E.G. job would ROCK.

I've seen worse, but MANY better die-grinder bench porting jobs....Much less 'professional' work. FRP is the man and all, and I tout him for being a die-hard KDX-er, but engine building isn't an "I think I'll start offering this service" type of gig, IMO.

From what you can see of the jug, it appears most of the 'porting' was in the intake itself. Only a slight eyebrow on the exh port, and some minor champhering (which anyone should just do themselves on any 2-cycle if it's going in for a replate). Maybe that's why he didn't like RB's carb....Cause it didn't work with the 1/4" of material removed from the intake port with no actual re-design of the port. :mrgreen:
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Post by green_passion »

>|<>QBB<
canyncarvr wrote:Please...a cliff's notes version of what you're having done?

Ported to what desired effect? To be tuned to race gas?

Piston from EG? Pro-X or Pro-lite?

I would appreciate very much a good pic of the intake port when you get the thing back.

Also would like to see a pic of your cylinder bore surface, see how it compares to mine..in my gallery.

Thanks!
No Problem! :D

Since I'm new, what's the story? That cylinder looks awful! :shock:

I'm only having EG port it to 225 and replate the cylinder because the nicasil plating on mine was chipping off. Not a huge difference but according to EG, it will help gain some additional power through the entire power band with only a minor loss to bottom end power without having to run race gas.

As soon as I get it back, I'll post some pics.

Now I wish it would hurry-up and get here! :grin:

***EDIT***

In addition to the porting, I'm also having the head mod done by EG since they need to be done together. :mrgreen:
Last edited by green_passion on 12:35 pm Apr 04 2008, edited 2 times in total.
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Post by canyncarvr »

Earlier it was noted that overbores from EG that have been specifically requested to run pump gas, don't. Keep that in mind when the detonation starts.

The cylinder is mine, was bored/replated through USChrome after a FRP port job. There is a piece of paper that is generally included with the return cylinders that explains metal porosity, and that some pits are 'normal'. I got this paper from FRP..not with the cylinder, but after I asked for a copy. The paper is some often-copied piece, with a goofy looking drawing on it (specs in a rectangle) that give the 'spec' for what is allowed, what isn't in regard to such porosity. Indeed, the paper (evidently from USChrome) says the pits are a GOOD thing, as they give oil a place to 'live'.

When I got the cylinder back I took it to two mechanics, both thought it was ridiculous. One guy said, 'I wish I could spend that little a time on a cylinder and charge that much for it.' Now...only one of these mechs do I know personally..and I would trust what he said. It was the one I don't know that voiced the above.

I had no end of problems with that cylinder. Detonation was awful. I could not run it on pump gas. I asked FRP about that. The response was, 'Nothing we did porting-wise would cause that.' That is the answer I expected, but..'ya never know until you ask, 'eh?

It was just after that I asked Ron Black if he would be willing to reshape my head..knowing I was already dealing with problems I couldn't resolve. He did. The bike ran better after I put Ron's head on..but it still detonated without toluene added to the pump fuel.

My exhaust was a splattering goober..ruining a few jerseys..making a mess out of lots of stuff. Jetting richer lessened to splatter, but it ran worse. The plug was a stark white... hot (BR8EG).

When once I had the pipe off for some general maintenance..I noticed something rattling around in the pipe..and dumped out a subport drum.

I took the cylinder off. It was out of round. That is why it detonated so bad (preheated mixture).

I ended up buying an OEM cylinder.
Last edited by canyncarvr on 11:25 am Apr 04 2008, edited 1 time in total.

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Post by skipro3 »

Keep in mind; the cylinder is getting bored to 225. No way Ron is going to carve a head without the cylinder if the stock bore is no longer the known standard. Ron carves heads to stock bores. I don't know that he can't do a head to an overbore, but I bet he won't. Too big a chance if something with the bore is wrong, he'll be blamed.
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Post by canyncarvr »

Where have you been?

In this instance, both the head and the cylinder went to EG for that express reason..they need to match, and the same person doing both is the only reasonable way you can expect a reasonable result.

Now...eat your dinner! :wink:

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Post by green_passion »

>|QBB<[/url]
canyncarvr wrote:Where have you been?

In this instance, both the head and the cylinder went to EG for that express reason..they need to match, and the same person doing both is the only reasonable way you can expect a reasonable result.

Now...eat your dinner! :wink:
Image
canyncarvr wrote: The cylinder is mine, was bored/replated through USChrome after a FRP port job.
Is the bad boring/replating on yours the norm from USChrome? :blink:
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Post by canyncarvr »

Pertinent question.

I don't have the answer.

Others on this board have had bad experiences with USChrome.

Some have not.

I'd certainly never use them again...ever..never..no way.

Like Inda said...you have a reputable, well-known engine builder as a mediator. (Well...the 225's that he's done that won't run on pump fuel that were SUPPOSED to run on pump fuel bother me.) It is reasonable to expect that whatever USChrome does must pass his critique before you ever see it.

Oh...the base metal porosity thing is something I can understand. But...Langcourt says they can plate up to something like .070" thick..and hone that result to a finished size. .070" is a whole lot more than the pits in the plated cylinder I got back. To their credit, Langcourt said they couldn't say anything specifically about my cylinder without seeing it..but they DID express curiousity over the whys and wherefores of a 'newly' plated cylinder being chock-full-of-holes.

I'll send it to them some day. I'd rather use the money to fix the hoodscoop on my mopar....... :wink:

One more thing....my cylinder was gone for something like eight weeks.

Have fun...waiting..... :neutral:

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Post by magilla »

I've been following along with interest. I'm about 3/4 of the way through building my kx/kdx hybrid and had planned to send my carb and head to RB as part of the build, along with a top-end.

A few years ago when I did the top-end on my kdx I worked with a mechanic friend in his home shop. The cylinder needed to be re-plated and not knowing much better I sent it to FRP for porting and re-plating.
I didn't take any photos back then, but I recall that turn around was about two-three weeks and both my mechanic friend and I where impressed by the port clean-up and the plating when we got it back.
Everything went back together smoothly and it's run great ever since.

Now that I'm thinking about sending my parts to RB it never even occurred to me till this thread that the FRP porting would interfere with RBs work. I'm hoping it'll play nice together.

I figure while the engine is out I should at least clean and inspect the KIPS, and if I'm going that far that I may as well toss a fresh piston in there. It's been about three years after all.
When I pull it apart I'll clean everything up and take some photos to post here.
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Post by green_passion »

>|<>QBB<
canyncarvr wrote: One more thing....my cylinder was gone for something like eight weeks.

Have fun...waiting..... :neutral:
:shock: :shock: :blink:

That's no bueno for me if that's the case. :neutral:
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