Need advice on getting low end back

[-copyguy-]

I bought my first quad last year, a 2000 400ex in decent shape. I spent some time learning to ride and then tried out a poker run. During the ride, I found out 2 things, first that my tires were worn out (for the mud I was going through) and second that I needed more clearance.

To fix both, I got a nice set of Razr2 22" rears. I knew that these would take away some of my low end, so I dropped the front sprocket down to a 14 tooth to try to gain some back. This helped, but not enough...I'm a big guy (~275) and need all the grunt I can get out of the engine when climbing a hill.

My ride style is fairly laid back and cautious (I'm still learning to ride), so top end speed isn't a big deal to me. I'm thinking of upping the rear sprocket to a 39 (or 40) tooth to help out, but don't know if the 39 will be enough.

Are there any other inexpensive ways to bump up the low end a little? I've got a foam filter on the machine, but other than the tires and the front sprocket, the machine is stock.

Yoshi or FMF Exhaust is planned for the future, but I don't have the cash for it now.

Thanks.

-copyguy-

[GPracer2500]

One tooth on the rear is a fairly small change--tough to notice probably.

This might help. I can't vouch for it's accuracy. Note that the stock redline is 9100 not 8250.

http://home.earthlink.net/~gellett/400ex.htm

[1fst400]

an exaust will give you all the low end you are looking for.

Untill then. you can always try a 13 front sprocket. them rear ones are to much money to just try it.

did you rejet when you put the filter on? if not that may be somthing to look into, just runs stronger.

is taking the air box lid off an obtion for you. I know mine is off at all times. I go throu some serious water sometimes. the water just beads off the filter when you have good oil on it.

[miller821]

Originally posted by 1fst400
an exaust will give you all the low end you are looking for.

Untill then. you can always try a 13 front sprocket. them rear ones are to much money to just try it.

did you rejet when you put the filter on? if not that may be somthing to look into, just runs stronger.

is taking the air box lid off an obtion for you. I know mine is off at all times. I go throu some serious water sometimes. the water just beads off the filter when you have good oil on it.
Ya def. save up and get a pipe and you will notice a diff. from it.. But also, someone correct me if i'm wrong, but a stage 1 cam should help, but I dunno what kinda engine mods you would need to accompany it.. But hopefully someone will correct me or add to me..

[1fst400]

ya a cam would wake thing up a bit. but then again so would a piston and port and carb. but I dont think he wants to get into motor mods. just easy bolt on stuf.

a rev box at this point, in my book is a waste of money. Not untill you have somthing like a full exaust and stage 2 hotcam, mabie porting and carb. are extra revs realy necessary.


but if you wanted to throw in a stage 1 cam it wouldent hurt a thing. But you wouldent see to much a difrence till you have an exaust to let er brethe.


note: exaust systems for these 400's go for cheep on ebay! I bought my Full LRD system for 200$. not bad!.

[-copyguy-]

Originally posted by GPracer2500
One tooth on the rear is a fairly small change--tough to notice probably.

This might help. I can't vouch for it's accuracy. Note that the stock redline is 9100 not 8250.

http://home.earthlink.net/~gellett/400ex.htm

Thanks for the link! It looks like a 13 in the front will give me more torque back with the 22's on than I had with a stock setup. I'll swing by the local dealer tomorrow and try to pick one up.

[speedracer13t]

I was in the same boat a little while ago. I put a procircuit t4 slip on, and rebuilt the top end. I am running the stock spocket sizes and now the quad pulls like no tomorrow. The TC woods cam helps a ton with the mid range. I am about 240 and it hauls me like a charm.

[MR.BIG]

One tooth on the front sprocket is eqivalent (sp) to 3 on the rear.

[400exrules]

i highly recommend an HMF slip-on. only around $220, you can pick different colors, sounds great, awesome low end power. I have 22'' holeshot XCT's with a 14tooth front sprocket, HMF slipon, stock size rear sprocket, uni filter, and a cam, and i can just chug up any hill i want without even trying. but i do weigh 150lbs

[-copyguy-]

Does a slip on make that much difference on torque? I had heard that the header made the difference on the low end while the exhaust can made the difference on the high end. Is this right?

Also, I'm on the cheap for right now, so I paid $13 for a JT Racing 13 tooth sprocket. It should get me by until I can get a nice Yoshi or FMF system on there. I have a moose filter in the airbox, so I may try to go up a jet size also...I still need to figure jetting out though :confused:

I always thought jetting involved just changing the main jet...I didn't know there were other adjustments in there as well...

Does anyone know of a good newbie style article on jetting that explains what all the different changes that can be done are?