Yes, I have tried all the combinations on the 400ex. Don't lower the rear sprocket. It won't pull it in 5th gear unless you are going down hill. The $30 bucks would be better spend on a case of beer.

 

Stock sprockets were pretty good for even my well built 440ex. Also, a side note, don't buy a 660 raptor either.

 

Why no 660? Explain?

 

2wd. 4wd should be just double the expense! If your in California. Go to Drive Train Direct in Corona. I noticed more power in top end also after the 4:10. Make sense? Before going up the hill I would do 80mph MAX! and now I have gone A LOT more.

I already paid for the stuff might as well try it. It comes next week. I noticed my old signature and I had a 44T on my old 250R Atc and went to a 42T and I didn't notice much. Different game?

 

Confused. As the others have stated, it give you more top end. Please explain

 

My 400 is a stroked 440. It has the torque of any quad I have ever ridden. I have 22' razr2s on it, at don't like the way it pulls 15/37, let alone 15/38. It will pull it, but I don't like it. I have ran mine at 16/37 with the 22's, but stay with 15/39 for a good gearing choice. With the stock engine, I feel 15/39 is the ticket, in the woods.

 

I ride mainly desert trails though.

 

It won't give you more top end unless you add at least 15 horse. There is only one reason why I could see lowering the rear sprocket on a 400ex such as yours. If you were running on a motocross track, flat track, or faster trails and were never in the bottom of first or in 5th gear and didn't want to shift as much. If you are running from the top of first to the top of fouth all day it would be ok but you would accelerate a little slower. It sounds like you are trying to gear it for mid to top speeds. Say to your self "when I get into 5th gear on flat or even slightly up hill terrane is my quad pulling very hard any more?" In my experience the 400ex won't pull very hard in 5th gear even with stock gearing. Lowering the rear sprocket will even make this worse. I hope this helps.

As for the 660 Raptor, you will get many different opinions on that one. Just start reading and doing a few more searches on the subject and look for people that have owned one and gotten rid of it. Not trying to start a big hoopla here because I'm sure many people love their 660 but just read more about it first and make your decision.

 

Also, if you are still going to run the stock length chain on it, I would guess you would run out of chain adjustment. Maybe or maybe not at first, but when your chain started to stretch after time. Just another small consideration.

 

Thanks. You did explain alot. One reason is not to shift as much. The trails here are mainly flate, more MX style I guess. I am rarely in 5th mainly in 2nd pinned through 4th pinned. I seemed to shift a lot when I am ridding.

I also did order a 90 length x-ring chain with the new sprocket to avoid the adjustment you stated.