Hello, just a little background info. I had a 400ex that I rode here in Ga. Must say it was a great ATV for this area with the tight technical trails that we ride here. Due to medical reasons and bills that come along with it I sold the EX. I could not get ridding out of my blood though. It has been my dream to get back to the sand dunes at some time in the future and I started looking at ATV's with that in mind. I keep reading about a few diffrent ATV's with the Bomb coming up on a regular bases. Then one day in one of our local papers I saw a Bombadier for sale. 2001 DS650. Long and short of it I talked the guy down from $3,800 to $3,000. I can't leave any thing I buy alone without going completely through it and make changes and upgrades. So I find every source on the internet I can on DS650's, this being one of the best. So what did I do? I took the info here and started making changes and so far this is what I have done. Repacked exhaust and put on an ODP tip, K&N air filter with outer wear, rejet carb (also cut the spring and drilled out the vacuum holes to 1/8) , new Sun battery, rerouted crankcase line and put a check valve one the end and last but least changed the upper A-arms out for a set of adjustable ones. Now I haven't got to ride any of the trails I am use to but we have behind our shop a quary with a few miles of trails through it. The changes have made all the diffrence in the world. Before the engine was peaky because it was not tuned right. Now it is smooth all the way to till the rev limiter cuts it out. Best improvement has been the a-arms. The bomb has great suspension but felt unstable now it tracks and turns so much better. So THANK YOU one and all for all the good info on this site.

 

Welcome to the forums! Also congrats on your results. [img]i/expressions/face-icon-small-smile.gif[/img]

 

hey 400ex where the hell are the vacum holes? did it make a differance when you drilled them out?

 

The vacuum holes are two holes where the needle attaches at the bottom valve piston in the carb. This is the same trick that we use on Harley Davidsons. It allows a stronger vacuum signal to the diaphragm is what I have been told. Yes it seems to work. Cutting the spring and drilling the holes makes the carb seem much more responsive. Check out this link, http://www.nightrider.com/biketech/hd_cv_mods.htm