I hate thumb throttles but grew up on a dirt bike. Just try it and see if you like it better. Probably will. As for the fenders, its not what you would expect. As already stated, you won't really notice except for water and mud.
I always used a stock swinger with more mods than your bike. Didn't need a +4 till I built my 4 mil. IMO, I wouldn't go any longer than +4 with 8 or 9 paddles. Have you changed sprocket sizes. They can make a big difference also.
Welcome to the HQ. Lots of great info and guys here. 460 cc is a pretty big motor to dune with. If its a 4 mil crank, it would have to be aftermarket cylinders to be that big. Post up some pics and you will get alot more info about what you have.
I'm going to do a flat black frame when I get around to it
http://i802.photobucket.com/albums/yy310/basanchez75/100_0065.jpg
http://i802.photobucket.com/albums/yy310/basanchez75/100_0063.jpg
This is usually a carb problem. Take them apart and clean them again. Make sure you have the slides in the right carbs. They fit in backwards if you put them in the wrong carbs. Look through the back of the carbs and you should see the cut out on the bottom. If its flat, they're in backwards. Put new plugs just in case. Good luck.
That seems like too large of a sleeve for stock cylinders. That won't leave much room for the transfer ports. The transfers aren't very big to begin with.
I've been reading this post for a few days to help decide where to camp. We are planning a trip for presidents. I've only been once in 2004. We camped at the very bottom of gecko road and it sucked. Miles from anywhere. My buddy told me to camp at the garbage flats. Where is that? Is it by the store? Thanks
Stock crank. Great shape. Checked by HJR. $75.00 plus shipping
http://i802.photobucket.com/albums/yy310/basanchez75/crank.jpg
Shift pro shift kit. Used for 3 trips. $65.00 new from cascade. $40.00 shipped
http://i802.photobucket.com/albums/yy310/basanchez75/shiftpro.jpg
Brand new All Balls bearing and seal kit for stock axle carrier. $23.00 new from rocky mtn. $20.00 shipped
http://i802.photobucket.com/albums/yy310/basanchez75/bearings.jpg
Stock front brake lines. Used. $20.00 shipped
http://i802.photobucket.com/albums/yy310/basanchez75/brakelines.jpg
Stock rear sprocket hub with 41 tooth sprocket. $ 25.00 shipped
http://i802.photobucket.com/albums/yy310/basanchez75/hub.jpg
PM me if interested. Paypal OK