Two Pipes?

Rob Hogenmiller · Joined: 20 Jul 2001 Posts: 850

I see there are two pipes out for the Rotax.

I'm wondering is one a Top End and One A Bottom End Pipe?

Bill Wright · Posted: Sun Aug 18, 2002 3:19 pm Post subject: Two Pipes?

>>I'm wondering is one a Top End and One A Bottom End Pipe?<<

No. As with almost all changes, their is little or no performance difference. Part # 273072 is the same exhaust, without the black paint of the part # 273073.

In this case, Rotax is, as usual, trying to cut down on mainenance time for the customer. Wiping those # 72 pipes down with ATF between races was just too time consuming!

Bill Wright
"Get on Course!" with FK www.formulakart.com

Rob Hogenmiller · Joined: 20 Jul 2001 Posts: 850

Thanks for the reply Bill, however the two available pipes I'm referring to have quite different cone sections.

I did a little more digging and as you mentioned the difference in performance is as not note worthy. I'd like to hear a Pipe Builder's thoughts though.

Maybe you can answer another question. I was lent a Rotax this past week and when we were on the track the baffle blew out, fortunately we had also been lent a rivet gun before we left.

I was surprised to see very little packing in the exhaust. I know the matting is a Spec Item.

Could you tell me is the amount issued spec also? Because this particular rotax pipe had just been rebuilt by a Rotax Center and it really seemed overly noisy to me.

Chad Stapleton · Joined: 19 Jul 2001 Posts: 4403

there was a Mk1 and a Mk 2 pipe for the max.
The Mk1 had a smaller pipe between the expansion chamber and the muffler. Rotax and most users claim there is no noticable performance gain in the Mk 2 , but why then change it ? ( i think it is cheaper to make )
Note;- the Mk 2 motor had a respec'd carb - amoungst other things.

adrian ward · Joined: 17 Jul 2002 Posts: 7

I have owned both the MK1 pipe and carb and the MK2 pipe and carb, and had them on the same engine. Yes, the carb is different on each engine, and basically the MK2 pipe and carb is a lot easier to tune, and that is why they changed it in the first place, there is virtually no performance advantage between the two. The packing in the exhaust should be replaced approx. every 10 hours, if you have less packing, you will reduce performance. If you are going to replace the rivets on the baffel, don't use aluminum rivets, but steel. Better yet use small bolts and nyloc of metal interferance nuts. The nyloc nuts doesn't melt as there is not enough heat at this end of the pipe.

Bill Wright · Posted: Fri Aug 23, 2002 5:09 am Post subject: Two Pipes?

Hi guys,

After reviewing more carefully my Rotax Technical documents I see that change occured starting with engine serial # 536536. Reason listed: ( and I quote) "Following the requirements of the market. Customers have been claiming operation of the engine at low and high rpm. -introduction of a new carburetor and exhaust system to improved function." ( end quote)

Be careful about using bolts/nuts on the pipe. I contacted the U.S. tech people, and they said it must be a rivet or it would not pass tech.

Bill Wright
"Get on Course!" with FK www.formulakart.com

Robert Gush · Joined: 07 Feb 2002 Posts: 50

quote:
Originally posted by Bill Wright:
Hi guys,
<snip>
Be careful about using bolts/nuts on the pipe. I contacted the U.S. tech people, and they said it must be a rivet or it would not pass tech.

They really ARE picky in your part of the world!

adrian ward · Joined: 17 Jul 2002 Posts: 7

Your right, they are picky about some things. SRA Karting, the importer for Canada, told us to use bolts because of so many unsafe retrofit problems using the wrong rivets!? The worst is the battery that is 4x the price it should be. I don't have a problem with a spec. battery, but don't gouge us with one that is less than reliable and price inflated. My primary sponser is a company called Battery Direct (the biggest battery wholesaler in Canada), and there are better and less expensive options on the market. I'm sure this will create a whole new thread, but fact is fact, and it is common knowledge throughout the world of Rotax Max on this battery issue. That's all!!