Doing some work with my 800 before snow flies. Dynamo Joe clutch kit, Boysen Rad valves, boost bottle getting the boot, reed spacers and thinking about a carb swap. I can purchase a set of carbs out of a '03 Summit 800HO from an engine shop. Does not these carbs have a hooded needle valve as well as a MUCH smaller main jet? Both are TM-40's and plumbing for DPM appears to be the same. Ideas?
With regards to the boost bottle, it is not on the '03 Summit 800HO! The carb intakes have the holes pluged from factory. May plug mine or see if I can have the Summit intakes included with the carbs as they will no longer work on the modded engine anyway.
Reed spacers. I now have the stock reeds, as well as a set of frayed V-Force 2's. When I install the Boysen can I not use one of the other set as a spacer? Gut out the reeds and use the frame? Thoughts?

Bobber,

Those are the carbs that we all needed in '01 and '02. They will obviously fit up correctly and should work mechanically. The big question is the MPEM/DPM on the '02 vs. the '03. We all know that Doo tried to work around some carburetion issues by tweaking the DPM and there was more of this in '02 than '01. So, with the large jets in the '02 my concern would be where the DPM is leaning the fuel delivery???

You might want to talk to Cyber-Dyne Research or Xtreme Performance about your switch. They both offer a '01 - '02 carb modification that essentially leaves you with the '03+ style carb with hooded needle jet. Interesting to note that Xtreme drops the DPM after this modification and mentions that the high midrange egts are still somewhat of a concern. This appears to point to the ignition timing curve as part of the issue. Here is Xtreme's write-up: Doo carb modification (http://www.xtreme-performance.com/snowarticles02summit.htm)

Hope this helps,

SummitAK

Edit: P.S. On the reed spacers you may just want to pay for new ones since the seal on these is critical. If you mod an existing cage flange the carb-side surface may not be true enough for use as a spacer. Maybe with gaskets it wouldn't matter??? If you can get the '03 reeds from the other engine you'll have the spacers already. You may want to check Bill Cudney's post on the Ski Doo forum. He mentions his testing shows the Boyeson RAD's don't offer more flow/power than the stock reed assemblies unless the internal vanes are thinned.

I know using the rad valves that there is an air box issue when using spacers. The rad valve allready sets the reeds back, and the have a thick aluminum flange. I think 800MXZ tried to use the spacers on his '01 with the rad valves and could not get his air box back on.

Perfect info guys! With respect to the "thinning of the intake" , the cylinders have been ported so its been done already. I'll keep you posted as I progress along and get some snow to try it out.