426 Arrow pipe

SFO

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#1
Went down to check out the Arrow pipe at the shop today, as it just showed up.
The basics so far are...
Silencer is 22" long with Ti sheath.
Comes with a intermediate pipe to fit stock header.
I got the optional headpipe, It is tapered going from stock dia(1.650" id) to the tapered section at 15" which brings it to 2"id all the way through the intermediate section.
The workmanship is an 8 on a scale of 1 to 10.
The silencer appears well made, but is not floating away. I will weigh it soon.
All of the joints are tight slip fits without gaskets.
The headpipe flange is a nice cnc aluminum fitting.
There are no instructions included and the distributor won't be able to talk to Italy until next wk. When they come back from vacation.
Arrow has made no claims regarding performance or what headpipe does what.
I will be running it on the dyno in the next few weeks to set up the carb for the pipe, super gas, and the Rohrich/Gore 97mm piston.
Any feedback about the merits of tapered headpipes would be informative.
I will include pictures when I get a little farther down the road.
Bill
 

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#2
I imagine the Arrow to be one of the better pipes. They are a lot quieter than most as well. The Europeans use them a lot including the FIM bikes. We get a round of the FIM world series down here in Australia and when you look over the bikes I would say about 60%, maybe more, use Arrow pipes.
 
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#4
Any feedback about the merits of tapered headpipes would be informative.
Bill,

Sounds interesting so far. I'll be looking forward to the dyno numbers.

Regarding tapered pipes, there are reasons for a tapered exhaust, especially in situations where you have an engine which doesn't deal with lots of flow really well at low rpm, but likes it when the engine speeds are greater.

Case in point, the two-valve XR200. This engine is a little finicky when it comes to exhaust tube diameters. Bigger is better for top end, but then the poor little thing stutters and stumbles on the bottom. An inserted header (smaller diameter bushing at the throat of the pipe) or a tapered design is helpful. But only if the taper starts out SMALLER than the stock diameter, then increases to larger than stock. The taper should be complete by the end of the first bend. Taper further back doesn't do much good.

That said, most modern four strokes - like the RFVC XR and especially the YZF - don't respond as well to the tapered design. Why not? Because the wonderful head design, cam design and additional valves pretty much do all that type of work for you!

Will a tapered header hurt performance? It can.

The tapered headers we've tested (the two most popular on the market today) didn't do well in shootouts against other systems.

In fact, in our WR250 tests, one of the most popular tapered headers (and most expensive) actually had LESS horsepower than the stock system at many points on the scale (at no point did it make more hp than the stock system).

This doesn't mean the Arrow system won't work - it may work very well.

It's really important these days to look at everything an pipe manufacturer has to offer. If EVERY pipe they build looks the same, no matter what model, you can pretty much bet that very little research and development go into each pipe. In fact, there are many four stroke pipe manufacturers out there today that just call up their pipe bender and say "make a pipe for me to fit this chassis". Not a great testing program!

In most cases, the "latest and greatest" design is just a rehash of something other companies tried years ago and discarded because it wasn't effective.

Don't discount the tried and true designs out there just because they've been around for awhile - in some cases, they perform better than the new stuff!

That said - I'll bet you can't guess the exhaust system which won our WR250 shootout?

The White Brothers E Series with disks (not the race tip).

Its overall performance was up to 40% better than some of the other aftermarket systems tested (using our hydro dyno). Pretty darned good!

Bill, if you'd like to compare numbers, I'd love to see a dyno chart of the Arrow system - I'll show you mine if you show me yours!
 
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#5
SFO and the Arrow Pipe

SFO,

I also have a 2001 426 and I have been trying to get information on the arrow pipe for my bike. My problem has been trying to find someone to order one for me. When you get done with your testing, I will be waiting to hear how you like the pipe. Also, I would like to know where you got the thing. I just checked Arrow's website, and it is not up and running. Thanks for doing the testing and then posting the results. I'm looking forward to seeing how everything comes out.
 

SFO

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Scuderia West, in S.F.

Is the dealer that is helping me.
The distributor is Speed and Sport in Livermore.
His email is-calss@speed-sports.com
BTW, If anyone contacts either one of these people/places in regards to this pipe please mention that you heard about it through DRN.
When I told them was going to report about the pipe they gave me a better deal. Its not hush money though...
If it doesn't work, or if there is anything I don't like about it, the integrity of DRN is my guide.

I spoke with Dale last night about dyno time and he is swamped doing pipe testing for Frank of Engines Only right now.
I guess he wants to find the best ttr pipe for his bikes.
It is going to be 2-3 wks before I can do a run.
Be advised, I am also running a big bore kit, race gas, degreed cams, so it isn't a strictly before after pipe comparison.
I didn't do a baseline run before I tore into it, so it is all pointless speculation from a scientific standpoint.
 
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#7
Re: Scuderia West, in S.F.

Originally posted by SFO
I spoke with Dale last night about dyno time and he is swamped doing pipe testing for Frank of Engines Only right now.
I guess he wants to find the best ttr pipe for his bikes.
We of course will be expecting a spy report on that stuff :confused:

Originally posted by SFO
I didn't do a baseline run before I tore into it, so it is all pointless speculation from a scientific standpoint.
But fun and interesting anyway :)
 

SFO

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It is fun, ain't it?

The distributors url is
http://www.speed-sports.com/Home/index.html
This has the part #'s and retail prices on it.

As far as the TTr stuff, that is classified!
Would you believe it if I told you a certain manufacturer of TTR components has made false claims in regards to the results that are actually being witnessed?
I swear it was alittle bird who told me:D
 
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#9
Re: It is fun, ain't it?

Originally posted by SFO
Would you believe it if I told you a certain manufacturer of TTR components has made false claims in regards to the results that are actually being witnessed?
I'M SHOCKED. It's hard to believe someone might have an optimistic horsepower claim attached to a product in the motorcycle business. Next you're going to tell me that the techno-giants at MXA don't really know how to jet a bike, or test a product, or...
SAY IT AIN'T SO BILL, SAY IT AIN'T SO :silly:
 
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#10
It's hard to believe someone might have an optimistic horsepower claim attached to a product in the motorcycle business
I'm always shocked when I hear the opposite.

It's been an interesting last couple of years in the four stroke industry. Now that four stroke performance $$ is starting to outstrip two stroke aftermarket $$, the two stroke companies are jumping on the bandwagon.

As soon as this happened - we began seeing those incredible exhaust systems which put out 8 or 9 additional horsepower from a 400cc four stroke!! Wow! Or how about a 5 hp increase on a bike that makes less that a horse stock (XR50)!!

It's been funny, and sad.