Stainless steel is more difficult to cut, roll and weld than cold rolled steel.  Back purge welding is required when welding stainless or the pipe will crack in the welds.  I know how much time it takes for us to make a HPR 19 with patterns.   Looking at your craftsmanship I think that I can see at least 25 to 40 hours of passion on your good looking project.

Stainless steel does not transfer heat as quickly or does not store as much heat as cold rolled steel.  These two facts will make a stainless steel pipe of the same dimensions and thickness as a steel pipe, come up to temperature a little quicker and will shift the power and torque peaks to a slightly higher RPM. 

I broke the labor up into small enough chunks, that I have no real idea how many hours I have in it.....but it is a lot. It is truly a labor of love.

 I work with stainless almost exclusively, so for me it's almost easier because I know exactly what it's going to do when working it. How much it pulls. How it flows when welding. How the set the welder for a perfect purged burn through weld....etc.

It came out pretty good, but the perfectionist in me wants to cut it all apart and roll the pieces back flat into patterns. I know if I did, and cut all the shapes out of flat metal, rolled them and fit them individually, it would come out better. Cutting and grinding the pieces to fit like I did left me with some pretty big gaps and significant differences in diameter between some of the pieces. But I'm not going to do that. Lol

I remember you mentioning the slight predicted raise in the rpm of the power curve when I asked you about making my hybrid pipe out of stainless. I don't want to sacrafice any potential power on my hybrid, but on this zilla I'm not too concerned. When I finally finish the hybrid the zilla is getting a ground up restoration and a stockish engine put back in it. It's going to be low maintenance, play bike.

Your turn Brian =)

I'll leave the pipe building to the pipe building professionals. But I do admire the passion that went into this stainless pipe.
 
On another forum (atvdragracers.com), I remember reading a thread about 2 stroke pipe design. A few members there were showing some of their home made drag pipes & left commentary on how each performed on the dyno. I always give props to those that wish to take on this endeavor. However, this brings up an interesting question... What materials lend themselves to making good useable power in a 2 stroke engine?

Quote from: PCS on November 17, 2013, 02:19:02 am

Your turn Brian =)

I'll leave the pipe building to the pipe building professionals. But I do admire the passion that went into this stainless pipe.
 
On another forum (atvdragracers.com), I remember reading a thread about 2 stroke pipe design. A few members there were showing some of their home made drag pipes & left commentary on how each performed on the dyno. I always give props to those that wish to take on this endeavor. However, this brings up an interesting question... What materials lend themselves to making good useable power in a 2 stroke engine?

It's not so much an advantage, it's just different. Let's say for example it shifts the torque curve 300 rpm up. Which drops peak torque 5 ft lbs. Changing the tuned length to shift the toque curve back down 300 rpm should gain most all of the torque back. I'm betting the percentage of difference after the tuning changes are made would be insignificant.

The major down side is that it could take building several pipes to get the differences ironed out.

I am no expert of two stroke pipe building by any means, so take this with a grain of salt. Jerry is one of the best 2 stroke guys in the business from what I know. I talked to him quite a bit about this when I had him build my hybrid pipe, and this is what I gathered from the conversation. I have also gathered this from what reading I have done. And I'm in NO WAY trying to put words in anyone's mouth, or proclaim to be an expert.

But because of my research and conversations with Jerry I did make a few small changes to attempt to compensate for the differences. I doubt I accounted for everything on my first ever attempt, but I've had a lot of fun.

Not to get off topic but is that a Polaris outlaw 500 in your signature photo? I only ask because a buddy that had been riding his 88 honda 250x since we were 14 just bought one for $900.

No it's the 525 ktm engine outlaw irs. Awesome trail bike other than it seems to be fairly high maintenance.

How does the yfzs do against it as far as power

The blue yfz is the faster of the two. It is a 15:1 compression 98mm big bore +3 stroker with ported head +1 valves, big cams, drag pipe, bored carb, fci intake, dynatek ignition with custom curves. My zilla is about 8 bikes ahead of it at the drag strip at little Sahara OK

Yeah you're probably right. Both yfzs beat the outlaw badly. I am pretty disappointed in the performance of the outlaw, but I still really like the bike. It rides like a Cadillac and has reverse. I built both the blue yfz engine and the ktm engine. The head on the Ktm flows like a river. It was 30 cfm better with similar porting to the yfz head, on my brothers flow bench. It has a 12.5:1 compression piston, for a max effort pump gas setup. Everything else is pretty much the same as the yfz, big carb, good pipe and intake, blah blah. The only thing I can figure is the weight and the IRS really really handicap it.



 P.S. I have raced probably a close to a dozen zillas with the blue yfz, and I have only had one (other than my own) beat it.

No. I joined powerstroke army and powerstroke nation but I have never posted on army and rarely post on nation

Most of them I have ran across were poorly equipped, as you can guess.  My point is, more or less, don't judge a book by its cover. I bet not one of them expected to get beat by a stock chassis YFZ.

I can't really compare the costs of the two builds. I bought that yfz with a blown engine. I had to buy everything anyway. Cases, cylinder, head..... It was all trashed. The only things I salvaged were all clutch and tranny related. That being said, it didn't really cost all that much to do that build. The stroker crank wasn't any higher than a stock crank. The big bore jug wasn't any more than a stock jug. I can go on, but you get my point.

The zilla on the other hand, since I do all my own engine work, was super cheap. The problem with it is pistons. At the power level it is at, I only feel comfortable putting about 10 hrs on a piston. I'm seeing .005 - .007 of collapse in the piston in that amount of time. That puts it up in the +.010 of clearance range, which is an audible knock if you are paying attention.

The way I see it, my yfz can't replace my zilla, but my zilla can't replace my yfz either. They are two complete different animals.

That is a great looking pipe. Good job!!!

I think what he's telling us, is he has built it to very tight fitting specifications and made several mods to it I assume. High HP engines tend to not last as long as mild mannered engines. which is dramatically affecting the life of the piston, as well as other components probably. I think he mentioned you could hear it slapping when at idle from the small tolerances.  At least that's what I'm understanding. It must make some incredible HP to wear that fast.

What about a billet piston?

Nice thread. Tight pipe! A work of art indeed. Pipe building is a black art. It is nice to see someone doing a project like this. A picture of the microwave pipe wold be cool. If anyone has some cone print outs you can send them to me:) $$$

That's fine its no big deal. You don't need to a prick about its only a pipe. Christ you act like someone is trying to bang your old lady.