Iīve just bought a zr440 sno pro -98. I checked the engine and It seems like the previous owner have disenabled the exhaust valve. Itīs always going to be open.

Does it matter if itīs always open?

Leave them that way if the powerband is OK. They are a real pain to keep clean and eventualy wear until they break. You will loose some bottom end and midrange but the top end will stay the same. You may have to reclutch to get the RPM's up quicker if it seems doggy of the line. When they break very bad and expensive things happen. Cat says they are to be replaced every 1000 miles on the '98 and '99 sno-pro's. I have seen several posts where guys have locked them open and claim it works fine. We are considering do this to my sons '99 as he has had nothing but problems with his. It is a very poor design and was changed in 2000 when they went to the servo activated power valves.

OK, thanks.

Iīll just leave them open then.
Looked up the price on new valves and they where really expensive!

I also cheked the main jetting and it was 290. Isnīt that a bit small? I have changed it to 340.

Did some reading about the jetting and you are suposed to get some extra hp with smaller jetts, but is it really worth it?