thunder alley pipe

can anyone tell me about the thunder alley pipe I here you all talkin about. I work at a yamaha dealer and we never heard of them.


Sure, I'll tell ya all I know.

Thunder Alley is a pipe that is "hand made" by Bob Murray. To the best of my recolection, Bob used to be a "factory wrench" for one of the KTM teams and is now on his own building pipes for the YZ's and the new CR450.

The concept is a new header mated to a megaphone in front of a muffler the size of a PC T-4. Evidently, the megaphone allows the still burning exhaust gases to expand and cool causing a pressure differential that creates a suction which actually sucks the exhaust out of the head improving flow. This is how I remember it as it was told to me, to be honest I wasn't paying much attention to the "sales" mumbo jumbo, I was more interested in demoing the pipe to see for my self if it worked or not (I don't care how it works, just if it works).

The quality is excellent and the performance is unmatched as far as I know (hoping to hear how the Dubach pipe compares soon).

The first thing I noticed when I met Bob was that he's one of the nicest people you could ever meet. I haven't talked to him at length, but he appears to have more knowledge about a 4 stroke mo-sicle engine than I'll ever have. So he's not just a pipe monkey, he really understands the dynamics of how to wring out a motor. Give him a call at 559-584-8109 or his cell 559-707-7325 for a acurrate synopsis of how his pipes work.

Bottom line is this pipe works beyond expectations, how often do you get that?

thanks for the info , ill give him a ring.

I know several of you have this pipe, can someone post a picture of it?


My partner got his pipe this weekend and

had good things to say, but then had to leave on business, so the compare (DRD vs. Thunder Alley) will have to be postponed one more week. I hope to post this time next week on the results! :)

Just checking in from Boston. As Soundchaser describes I got my pipe last weekend. Had just enough time to put it on and take a quick ride before jumping on a plane. What can I tell you, the only sound the Soundchaser will be chasing next weekend will be coming from the back of my exhaust. :)

Just having some fun, but the pipe made the bike much faster, especially mid to top. I went to a 168 main(was at a 162), raised the clip 1 position and backed the fuel screw out another turn. Still felt like I may be a bit lean down low. Will experiment this weekend and compare with the DD pipe and report back.

Okay wait, which one of you has which system? My vote is for the Thunder Alley. I bolted it on mine at one of the Elsinore Demos and without any jetting changes I was completely blown away by the power increase!!!

Are you guys going to swap systems to personally compare them seat of the pants means? I would think this is the best way to do it.

Ya, it's hard to beat the Thunder Alley pipe. I was very impressed when I demoed it. I was able to feel the difference from bottom to top for example, I was able to clear the start finish seat hop (table top) on the vet track at Elsinore with the Thunder Alley, I wasn't able to with the stock pipe. The difference in distance was about 5 feet. Considering this jump is only about 25-30 feet long with the same length approach, this 5 foot difference is considerable. Then you have the mid to top improvement that will blow the graphics off anyone next to you! It's an excellent pipe and I'll bet it's as good or way better than the Dr. D pipe....we'll know soon enough!

Hey Thumpy;

I'm unable to clear that thing too. I'm in the process of trying to decide what pipe to get. Was going to just get a spark arrestor, but the price is a rip for what you get. You installed the T.A. exhaust on your bike with or without jetting it? Also, does it have a S.A.?


They do have a spark arrester model, but it isn't yet approved (as of a month ago, it may be by now) by the forest service. I demoed the spark arrester model and didn't like it as much. It has a smaller stinger opening (forest service regulations) which restricts flow a bit too much for me. I re-jetted for the BK mod and haven't had to touch it since. Call them and see when they're gonna be at Elsinore again (I think it's either this coming weekend or the next) and demo one for yourself! Be forwarned, you should bring your check book you won't want him to take it off.

p.s. Try that jump with your pipe then try it with the T.A. pipe and see what happens.

Sound Chaser,

I'll look forward to your report. It'll be interesting to see how it pans out. As most everyone already knows, the Dr. D pipe was rated the best pipe for the 426 in the magazine shoot out. So, we may just see how the Thunder Alley stacks up.

I thought I'd pass this bit of info along...

I just talked to the guy that makes these pipes (Bob Murray) and he said he sent one to a guy in England who dyno tested the regular pipe (non sparky) and got 6 extra ponies on top! That's what I call bang for the buck.

He also said he's only making one a day. He does all the bending & welding himself. I was calling to order one for a buddy of mine and was surprised to hear there's a waiting list (as of now only a few days).

[ December 05, 2001: Message edited by: thumpy ]

:) Ive got a thunder alley pipe and it plain rocks. I did the BK mod at the same time as pipe and spent most of my next day riding re-learning my bike. My thumper makes power like my CR500 now. But at least its rideable, unlike the CR. Plain and simple, Im not man enough to ride that CR anymore. At any rate, I love that Thunder Alley pipe. :D

Yeah, he hand makes the entire pipe himself. Remember that when you see the system and you'll be REALLY impressed. The muffler/silencer is all hand rolled and welded together WITHOUT FILLER ROD, he's just heating it up with a torch and melting it together. Go out and look at your silencer adn tell me those welds don't look insanely impressive without filler rod!! I honestly don't doubt the 6HP on top. I actually never opened it up while I was testing it but the power increase through out was mind blowing enough that I almost looped out pulling away from his truck cause I wasn't expecting that much improvment.

No one has a picture of one of these pipes? I've heard that pipes don't make more power on the 426, just move it around. What is the difference with this one? You would think with all the large companies and their tesing, facilities, etc, that they would have found this extra power if there were any. Now if this pipe makes 6 more HP than my stock one, I must have one.

I'm sure if you called Bob Murray and asked he'd send you a photo or something. 559-584-8109

I think only one person that I know of one this board actually has one on their bike right now. As for the 426, a guy on a WR426 (don't know if it was YZ timed or anything) was testing one while I was too and he was very impressed with it. I don't know what 6HP on our bikes feels seat of the pants but on my YZ400 that pipe made my bike come alive!!! It was REALLY impressive. I'll definately be getting one someday. Probably close to my B-Day in May because I've got some other priorities on my money spending that's going towards one of my vehicles before I dump $350 into my bike that actually runs awesome right now. BTW this pipe is loud but it sounds AWESOME!!!!

I just got off the phone with Bob Murray - what a nice man. He seems to be a very knowledgable person. Anyway - here's the scoop. Header & Silencer - $350. Silencer only - $250. He says that he makes absolutely no changes to the stock head pipe - the stock one is a very well engineered piece. All his performance gains come strickly from his megaphone silencer's design. He explained to me how it works but he lost me early - something about creating vacuum. Whatever, I believe him and I want one. This guy should be working for NASA.

He just finished setting up with a Web company and hopes to have it up and running by Monday. He's not sure, but right now he thinks it will be We will finally able to see what it looks like. Bob says his system looks a little like the Pro Circuit T4.



MXer303 the main reason the pipes most people make dont make much difference is the pipes the make arent much different than the stock unit. Basically your looking at straight pipes, except for the Thunder Alley pipe. Its a reverse cone megaphon pipe. Think of it like an expansion chamber for fourstrokes. The graduation of the inital megaphone allows the still burning mixture to expand creating a suction in the head pipe. The key is the correct sizing of the headpipe and the megaphone. All I can really say is, mine rocks :)

Just spoke to Bob. He plans to be at Elsinore MX the first or second week of January. He said he would be out there sooner, but he doesn't have any product to sell. (He can't make them fast enough to keep up with demand.)

The canister and the head pipe are the only things resembling the Pro-Circuit T-4. The rest is pure art!

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