thunder alley pipe

Does it weigh more than stock?

The ole lady just ordered me one for X-Mas. I am soooo jazzed. My pipe was no.5 on his list and he says we'll have it in 1-2 weeks. Now I'll have to figure out a way to blow off the in-laws on X-Mas so I can go do a little testing. Yeah right. Now, let's see what else is on my list. :)

Hey Thumpy - about the sound. I understand it's a little louder - that's OK. But what system would you compare the sound with. Just curious.



Can someone please take a pic? LOL This pipe sounds like it is great...but does it look OK? What pipe does it look like (ie R4, WB E series, PC T4, etc)? How much is this pipe? Thanks,


Hey guys,

The sound is equivelent to the Pro-Circuit, which in my opinion isn't too loud (personally, I love the sound of a growling thumper). Odie, I hear you guys are getting unusually nice weather right now, let's hope it holds till you get your pipe. You're gonna love it.

Cost is $350.00 for head pipe and muffler (the whole shmeer), $250.00 for just the muffler (megaphone) section.

Weight is said to be one pound less than stock.

The head pipe looks identical to any of the other aftermarket pipes. The muffler section is where the magic is. Picture the pipe connection going from the standard diameter then gradually getting fatter, like an expansion chamber, until it's the same size as the cannister of the Pro-Circuit cannister/muffler (like a megaphone would look). Internally just before the cannister is a forcing cone (not visible). So to look at it on the bike you wouldn't notice anything different because it's (the megaphone) behind the side number plate. Hopefully, we'll get a picture of one soon.


this pipe will do to the whole powerband what the BK mod does to the bottom of the power band. It improves it from top to bottom, dramatically. You doing 140 foot leaps would really benefit from this pipe. I'll bet Bob would let you return it if you weren't happy with it (he knows that'll NEVER happen so it's a safe bet). In fact, what he does is he'll call you when the pipe is finished and he's about to ship it, to let you know when to expect it. He'll enclose a bill with it and you simply send him a check after you receive the pipe. No COD or anything. That's the type of guy he is, he believes in people, an amazing attribute these days.

I looked at a Dr. D pipe and it appears that they are trying to get to the same place (more power) by using gradually bigger tubing, thereby increasing the diameter incrementally toward the muffler. Nothing in this mind set really makes a significant difference, a little yes, a lot no. It probably will help a ported and polished head, which I'll bet Mr. Dubach has, whereby the Thunder Alley pipe will give you the benefit of flow near what you'd have if you had the head ported and polished. Next question, what's "near". I'll leave that up to you to decide. Those that have demoed this pipe know what I'm talking about.

[ December 06, 2001: Message edited by: thumpy ]

I can guarentee any of you that the pipe looks very nice!!! It looks like something a large compnay (Pro Circuit, White Bros.) would build but you know it's just one guy with some really talented welding skills and a good design. I also guarentee that none of you will send the pipe back. If I had my check book on me at the track that day the system would not have come off my bike. I've been riding for 16 years and never looped out on accident. That day pulling away from the truck I was not expecting THAT MUCH power increase and I clicked into 2nd and twisted wide open expecting the front to come up a little and I almost went over backwards.

Hey guys, just wanted to weigh in with my opinion. I got my pipe on my bike last week and then had to travel. Have not been to the track(racing this weekend) but did some fire road riding near the house. The pipe wieghed less than stock. Did not use a scale, but just holding them it felt less than stock. The fit on the bike is great. There is no gasket or clamp required, just a perfect fit between the header pipe and canister. The routing of the header pipe is much better than stock - it does not stick out as far(so will get damaged less) and gives better access to the filter. The canister stuck out a little further than stock. It actually made contact with my number plate and melted about a 1/8" square section. I need to find a fix.

The power was incredible. I need to work more with the jetting. I kept going richer and it kept getting faster. Ran out of time and larger jets so did not dial it in. The mid-range power felt much more explosive. This was great, but you do give up some throttle control. I sure part of it is getting used to the power, but I did find I was riding it more like a two stroke and using the clutch more to control the power. I will ride this weekend and see what adjustments I need to make.

In second and third gear the front wheel was lifting all the time coming out of corners. I am running a 50 tooth rear sprocket, this may allow me to go back to a 48 or 49, I need to see how the low end torque would handle that.

Will post again after the weekend. I will also be comparing it to a DRD pipe.

Finally, in talking with Bob, he said most of the power gains came from the megaphone. The megaphone is working as a secondary combustion chamber for unburnt fuel that then generates a vacuum and is "sucking" the exhaust from the bike. Kind of similiar to a two stroke.

Hey Luv-er,

Get on the damn plane and get back here. I dying to try your bike out with the TA pipe. Having the DRD pipe I find it hard to believe that your getting so much power outta this pipe, of course Im biased already having the DRD pipe and being very happy with it. Aesthetically, I have to say the DRD is a better looking pipe, but we all know, looks doesn't win races or get you the hole-shot ! :)


Try and wrap the pipe with "header tape". That may fix the melting plastic and will also improve the already vastly improved performance. I'm thinking I'll wrap mine in the megaphone section only for same reason. Now the trick is finding the tape.

Damn Guys, Some needs to post a picture! I would love to see this thing. What is the system made of? (stainless w/ alum can, nickle plated steel, ect.)

Thanks for the info,


It looks like it's made of the same grade steel that the Pro-Circuit "Works" pipes are made from. Bob recommends spraying it down with WD-40 after a wash and spin down the street. It is a sweet looking piece of metalurgic art. The can looks very similar to the Pro-Circuit T-4 can.

[ December 07, 2001: Message edited by: thumpy ]

[ December 10, 2001: Message edited by: thumpy ]

Cool, Thanks Thumpy. I wonder if he'll do a ceramic (Jet Hot, ala Big Gun) coating. That would be sweet looking and probably make even more power.

That's not a bad idea. I would imagine he'd probably let the buyer work that out though (it'd probably be cheaper that way, you cut out the middle man). I'm gonna look into that...

Lovemythumper try this, my Pipe didnt touch but came uncomfortably close to the side plate. When I demo'd one, it melted the side plate too. But what I did was to swap the big spacer/washer at the end of the pipe near the seat with a standard thickness washer and I stacked 3 washers between the mount and the subframe and the pipe. No problems. Loosen the headpipe when ya do this, but tighten the head pipe first when snugging the whole system up to make sure ya dont get a leak at the cylinder head. Gawd I love the way that thing sounds! :)


That sounds like the ticket. I'll give that a try.

Guess I'll be the guy in England who dyno tested the pipe this week...

To set the record straight - the Thunder Alley pipe didn't give me any more top-end power. It gave _very_ good bottom to mid performance at the expense of a touch of top end. Note that I was limited for dyno time that day, so didn't go up on the main jet, but the mixture was pretty close to ideal.

We talked about my bike modifications and dyno runs, and sure enough the bike is roughly 6hp up from stock (98mm piston, flowed head, open airbox etc). Bob seems like a really nice guy, and I'm sure it wasn't an intentionally misleading figure..

FWIW - I'm very happy with the pipe. It's light, well constructed, a good fit, and sounds gorgeous.


Jon E.

Nope, you're not the guy.....he told me the guy he talked to went by the name of John! :)

Did you hear that, that was my bubble bursting...

I can attest to the improved bottom & mid, I noticed that right away. Our tracks here are not the GP type you guys have on your side of the pond. So we rarely see the top end (or 5th gear for that matter). So I didn't notice any loss of top end as I don't rev her near the limiter.

What pipe was on it prior to the T.A. pipe? Did you dyno it with the other pipe for a comparison.

As usual, very curious.

I was comparing with the stock pipe, back to back dyno runs on both..


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