XR400 and some MX riding questions

[DougTx]

I have a few questions I was hoping I could get some answers to if that is ok (opinions are fine too)

I have a 2002 XR400R (Honda)
It is 100% stock in the suspension department to my knowledge and the bike has a better carb but other than that is 100% stock also.
I am 6'1" and 255 lbs
I am a realtively new rider (back after 25 years off) and am riding trails some and more and more am liking a local MX track at my park.

When I ride, I notice a few things;
1. My bike is really heavy compared to other bikes and two strokes. I suppose that could only be remadied by changing bikes or me loosing more weight ( I am working on it and amd on the way down in last year)
2. When I ride the MX track, the front end dives more than I like in corners and if I go in a little more aggresively when I shift the weight to the back of the bike on acceleration out of the corner it does not feel really stable. Is this a result of me being to heavy for the suspension? I do not know the history of a rebuild on my suspension.
3. When I take table tops or the rythem section of the track it seems like the bike does not want to stay in a straight line when I go faster. I am hoping some practice will work some of this out but also wonder if suspension has something to do with it.
4. When I jump up on the table tops or down from them (no I do not clear them I am still kinda new to all of this but I do get up in the air) the suspension does not bottom out but I can tell I am working the front end at least pretty far down and it can sometimes cause some stability (like left right motion) after landing... at lower speed and distance this does not happen, it seems to happen with speed. I am pretty smooth I feel and it is not super far but the more I am getting more comfortable jumping I am noticing it. I have tried repeatedly and even back down to try to see if it is me. Could be but wanted to ask. ( I had the mechanic check bearings when I just had it serviced and he said they were great if that matters)
5. I really like my bike but I also realize it may not be designed to do the things that I am doing (but at my basic skill level I seriously doubt I am asking it for more than it can so far) but my question is this. If I get more and more comfortable jumping and riding the track (I enjoy it way more than I thought I would) will paying to have the bike sprung and valved for me make my bike at least remotely capable on the track for non-supercross but some fun and more spirited riding on the track? (Taking a double etc..) or are there other parts of my bike that will make this not good for it if I go that far (frame, general construction etc)?

Reason I ask is that if it is just a function of putting some money into doing the suspension right and it should be great then I would not mind diong it. If my bike and the suspension, frame or some other part of it are not made for this kind of thing I do not want to sink a lot into it and would consider changing to a bike that I may be able to trail ride more but would be more adept to this kind of riding.

I know a little but not a lot so anything would be appreciated. I do not mind investing in something I love but I really hate to waste money and do not want to head down a path that I would end up turning on later by trying to make a bike into something it is not and spending a lot of money doing it.

Thanks....

 

[Matt90GT]

The bike is designed for woods riding. Plush and take the small stuff. Also the designed rider weight is probably closer to 170-180lbs.

So first off you need to get the right springs in the forks and shock. New oil in both would help also. After that if you are still unpleased with the ride, things get more expensive. Either get a track only bike like an older CR250r or newer 450r bike - or - swap a set of late model MX CR/CRF forks on the bike - or - revalve both ends of the bike.

Just remember that is a offroad XR bike. It will have limitations for MX riding. Your best bet is to keep it for a woods bike and buy a late model MX bike for the track.

 

[James]

Don't bother trying to set the XR400 up for mx... especially at your weight.

The frame flexes too much, the suspension is too soft, the steering angle is too steep, the wheelbase is short and the bike is heavy (top heavy to boot) so it will always wallow around and feel less stable on jumps and whoops etc than an mx bike. The faster you go the worse it gets. If you get the suspension set up stiff enough, the frame will start to bend particularly at the footpeg mounts. You will have a hard time getting the stock forks right for serious jumping. If you can get the handling somewhat setup for MX, you will promptly notice its lack of power and too-wide gearbox.

I went through this whole process with my first XR400 in 2001. After 3-4 months of expensive experimentation, I bought a used CR250. I'd say definitely buy a mx bike for mx, you will be glad you did.

 

[XRpredator]

while James speaks true, the XR can be fun on an MX track.

One of the first changes I made when I had mine (and I wish I'd told you this sooner) was to replace the stock 0.38 fork springs with 0.43 springs. That made the front end a lot less prone to diving. I believe you can still get a fork stabilizer from Summers Racing Components, and Pro Circuit used to sell a stronger footpeg mount to prevent breakage on hard landings. You'll have a hard time getting high-speed stability over those whoop sections because the XR is short-coupled and steep-raked, but that's what makes the bike such an awesome mount in the woods. All you gotta do is think about turning and you're around a switchback.

But, no matter what, even though you'll have fun on the XR, you'd have more fun on an MX mount. That being said, my XR survived about 50 more pounds than yours will endure ;)

 

[Patman]

Even my highly modified XR250 with KX125 front end and modified rear shock is not a MX bike. Then again that's not what I wanted it to be so it sort of worked out. XR's just are not in the same class as MX bikes on a MX track, just like MX bikes are not going to be well suited for tight woods or long trouble free runs through Baja.