My First Supermoto! XR 400

Hi All.


I have just brought home my Honda XR 400 and would love any advice/tips about maintenance etc. 


I read many, many reviews about this bike before buying and everyone just talks about how reliable they are.


Also what aftermarket exhaust is best to put on? 


I'm from the U.K. so I wonder if there are many others living here? I know these are very popular in America.


Nice to meet you all and thanks in advance for any help people might be able to give.




I think most prefer the "big gun" exhaust. I have heard that you can't get much better than an uncorked stock 97 exhaust. The most important mods to mine so far were revalving the front forks and installing a certain transistorized rectifier.

I still would like to lower this bike and stiffen the springs a bit.

Most will tell you to check the valve clearance, I tell you it was tricky for me, the auto-decompression made it difficult to check the right- side valves you gotta be extra sure that deal is not opening your valves on that particular stroke ...

Edited by some guy

Thanks for the reply some guy. 


This "big gun" exhaust.. Is that a brand or are you referring to the stock 97 exhaust? I'm just looking for a great tone (not saying my doesn't sound quite meaty at the moment).


Whats this transistorized rectifier you speak of? and the reason you fitted one?


I think a service is always best when buying any second hand bike even if they say they've just done it. :) 


Ill leave the valve clearances for my mechanic I think :).

"Big Gun" is a brand name. FMF also has a couple different slip on cans that will fit. 


Congrats on the XR,, looks good!  :thumbsup:


Maint. tips -


Get 2 or 3 oil filters at a time (OEM filter is fine). Use a good full synthetic oil (or semi synthetic is fine also) that is approved for use with wet clutches. Some of the fancy oils have extra stuff in them like moly, that help with top end wear but will make your clutch slip. Don't use any oil with high mileage addatives etc.


Get yourself set up with 2 air filters. That way you can always have a clean one ready to go on. Swap them out, clean and oil the old one then set aside in a plastic bag for when you need to swap it out again. 


Get a manual (buy one or find a PDF online you can download). This will tell you the proper way to check and change the oil and a bunch of other questions you will have eventually.


If you don't have one already with the bike, get a spark plug socket from Honda so you can change it if needed. Regular sockets will not fit in the space around the plug, they are to big around.

Fh020aa that is the only rectifier that would eliminate me electrical issues from the aftermarket 200 watt stator installed for my lighting system.

I fried a few regulators before that.

Cheers for the info Michigan  :thumbsup: . I have just bought Motul 5100 5L for £33 including a K&n Filter on ebay. Draper seem to sell a spark plug tool that fits the XR400 for £10.


The prices probably don't help you as i'm guessing your from the states?


Aftermarket exhausts seem extremely hard to come by over here in England :thumbsdn:


When it comes to electrics and stuff I just end up switching off (pun not intended lol).


I want to put indicators back on and I've already got the switchgear on that allows it and I think the seller said the wiring is almost done too, just no indicators themselves. Will probably be a job for my mechanic to save me the Headache.


Cheers for the info lads. 

Oh also.. I've got the original trail wheels. How long does it roughly take to swap them over? Not to much of a big job is it?



Well, I have different rotors, spacers, and smaller gear for the sumo wheels. So as long as you ain't gotta mess with chain length and have spacers right it's not too bad.

Make sure you keep that K&N filter clean and oiled. They flow well but don't seem to like fine dust. Probably not something you will run into much but be aware of it and clean it up if you do. For street riding and off roading where there isn't a LOT of fine dust or deep water they work just fine. Enjoy the bike and have fun!!  :thumbsup:

When I say "k&n filter" I mean oil filter. Ill have to get an air filter soon  :thumbsup: . Cheers for the help lads, can't wait to get out on her tomorrow!

Welcome to the XR400 world, nice looking ride, when you get time check your swingarm bolt , remove it and lube it at least yearly at minimum.

Hi mate, thanks for the welcome  :thumbsup: . The guy in the ad said that it was running nice and free and stated this is a common issue with the bikes. Of course I will be handing it to my dedicated mechanic to give her the once over. She needs a new throttle cable as this one is sticking and not smooth to pull back. 

Nice looking bike! Get some off road tyres ready for some laning :D

I think most prefer the "big gun" exhaust.

Curious why you think that? Big Gun are mostly really cheap (cheezy cheap) with very little baffling.

There are some that buy them because they are cheap, but I never see anyone that thinks they are "good", much less the choice. ;)

Yeah the big gun evo 2 has been tested to outperform the competition on the xr guess I should had specified which but they are certainly not cheap.

If I had one I'd change the forks but that's just me

Yeah the big gun evo 2 has been tested to outperform the competition on the xr guess I should had specified which but they are certainly not cheap.

 But even then, they perform well because there's next to no restriction in there.  Super light, super flimsy and not much baffling.

 Very loud = good flow and good performance. but,,,,,,,,,,,,


Quite a few stories of them blowing/rotting out the rivets holding them together, sometimes the 1st or 2nd year.

I bought one for my 350 some years ago and it was so cheaply made I sent it back. Felt like I could dent the aluminum muffler with my thumbs if I pressed hard.

For sure any kind of impact in a crash was going to dent it badly.  Like a big Coke can.  LOL


 never seen an Evo, maybe they are a lot better. ?? They'd HAVE to be.   ;)

Edited by MindBlower

Nice looking bike! Get some off road tyres ready for some laning :D


Already got them Mike! Came with the bike which was such a bonus! You can just about see one of them in my picture if you look towards the headlight  :thumbsup: . About 10 mins from my house I have tracks waiting for me too!  :ride:

Also does anyone know what FMF slip ons would be a direct fit? I've not found a single website that sells exhausts the for the XR which is quite annoying!


Of course on ebay you type "xr exhaust" but it just leads me to the US which I don't want to have to do.


Maybe if I can type a certain FMF pipe there will be some for sale over here :).


Cheers for the info so far lads.

Maybe look for a "Leo Vince X3" slip on. Might be easier to find over there. Usually a little cheaper than a FMF Q4.

You ought to check out xr's only

Website for exhaust ...

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