Top end longevtiy?

[ATC350X 85]

To the guys who have 450r's, does it say anywhere in the owners manual how many hours you are supposed to get out of a top end or how frequently you are supposed to do it? Also how much oil does the engine hold? I was gonna buy one and my friend thats a Honda parts guy talked me out of it saying it was high maintenence ride so I bought a 99 400ex and its nothing like my old ATC 250R so now I gotta sell it.

[Manny55]

Not to be rude, but that was stupid hehe!

[ATC350X 85]

I wasnt looking for opinions:blah:

[Bretmd94]

its more reliable than your old 250r probably. Well worth the buy. It hold less than 2 quarts of oil total. And less than a quart on the crank side. This means yes the aoi will have to be changed often, but its a very fast and easy process compared to most quads.

[ATC350X 85]

So does it say anywhere in the manual how often the top end should be rebuilt? The ol 250R was on its 1st top end until 2002 until the head and base gaskets started leaking. It was only .0005 over spec for piston to cylinder clearance. That thing was mint I got $2400 when i sold it a few months ago. AS far as 2 strokes go that thing didnt get more reliable, just as reliable as my 350x.

[kbass24emtp]

There is nothing mentioned in the shop manual about when to rebuild the top end.

[ATC350X 85]

How about in the owners manual under the maintenance schedule?

[kbass24emtp]

Nothing listed in the owners manual either.

[ATC350X 85]

Damn cause i was told that the Crf 450 had it in there and it was somewhere around 20 hours. Like a 2 stroke. I could see the being it only has 2 compression rings and no oil ring, but I was wondering what they said about the trx450 being that it has the 2 compression rings and the oil ring, like most motors do, maybe its just run it till it smokes, (which will hopefully be never, if i buy one)

[86atc250r]

The 450R should require top end maintenance less frequently than a 250R.

Now - for my opinion...

Having come off a lightly modded '86 ATC250R myself, when I bought my first 400EX 5 years ago I made several direct comparisons.

First was, yes, the 250R felt faster and made you feel like you were riding a lot harder than the 400EX did --- The first ride I got on a 400 I remember thinking it was sort of weak - until I put a little more time on it - I eventually found it's good handling caused it to be deceptively fast... Also, much to my surprise, in a straight drag race the two were practically dead even.

I found that I could ride much faster on the 400EX, everywhere. I also found that I could ride faster for longer - the 400 didn't wear me out nearly as much.

All said and done, I really haven't ridden my 250R much since.

Now I have a couple 400EX's, had and sold a Cannondale, and also have a 450R. I still race my 400EX in the woods, and am still setting up my 450R & will likely configure it more MX style.

The 450R does put out a lot different and more power than a 400EX, but don't be so quick to abandon the 400.

First thing you need to do is to check the throttle adjustment. 400EX's are shipped with the adjuster screwed all the way in, which puts a bunch of slack in the throttle cable and doesn't allow you to reach full throttle - as a point of note, 450R's are shipped the same way.

If no one's ever fixed the throttle adjustment, your 400EX will be way down on power.

450r vs 400EX? Well, it depends on what you're doing with it. If you're mainly trailriding with friends or racing local woods races, I'd definitely recommend you stick with the 400. If you're just after a fast quad to impress your friends, like to play around on a MX track, dunes, or ride a lot of open, higher speed trails and are agressive enough to use the additional power, then a 450R will have it's advantages...

Good luck with your decision.

[2004TRX450R]

I haven't looked for an actual spec but I'm sure it will last a LONG time provided you maintain it properly. Probably longer than your 250R.

The CRF does not have two compression rings and no oil ring. It has one comrpession ring and one oil ring. The 450R has two compression rings and one oil ring. This will make the top end last longer and be more reliable. It will also help it to not burn as much oil as the CRFs do.

Comming off an ATC250R myself I don't think I completely agree with what was said above. Mine is modified but not heavily. In the trails on the dirt the 400EX and 250R in stock form are probably pretty comparable in power and speed. However just by adding a pipe to both the 250R will jump out in front. ESPECIALLY if you ride in the sand. Even stock for stock there is no comparasin in the sand. The quick reving 250R will take the 400EX hands down. Also what was said about the handleing and the 400EX being able to be ridden faster that is kind of a given comming from a threewheeler to a 4 wheeler. Heck that would probably hold true for a 250X vs an ATC250R. So it isn't really a good comparasin.

I don't think I would take your buddies advise anymore. He doesn't sound that knowledable about it especially for working in a bike shop. The 450R is better in pretty much every aspect than the 400EX. Not to say the 400EX isn't or can't be made to be as good or better than a stock 450R but stock for stock the suspension and power is better. I would buy one for trail/woods rideing over a 400EX anyday. By the way I do have a 400EX too and notice in my sig where it is going!:D

[ATC350X 85]

Well, my 250r was a basically stock ATC with a Answer s-11 silencer and a uni filter. It would beat me up if I rode it hard for about and hour, bashing it constantly down the nastiest whoopies. I would just go as hard as I could, ya know. Now as far as riding my 400ex compared to my 350x the 400 has better suspension, it bottoms out alot less in the rear lol and I can fly down the whoops in a tuck all the way back over the seat, the 350x i can do the same but it bottoms out and beats me up. I want something I can tear it up and ride at the track, I ride mainly in a sandy power lines track that you can definitely open your bike up on esp with good suspension. I think a 450R will do that quite well, and I want to start jumping more. In the past i didnt do too much jumping, all my ATCs had whooped suspension, so it hurt, ya know. I also want to head up to Raceway park and it hit up the MX track. I was considering looking for a trx 250r but they are so hard to find in unmolested condition and thats what I like a bike that hasnt been monkeyed with.

Now I also like to ride slow sometimes and just F around in the mud or just hitting some small jumps, so the 450r will probly be ok for that. But i have a back up plan for that, the swap meet is this friday and I plan to get a atc 200.. s, m es, or a 250 big red if i can find one under $500. That will be my go slow toy and I dont want to abandon ATC's I grew up on them and feel connected to them. I feel they make you a better rider when you step up to a quad. Quads make you lazy when you go back to an ATC, there is much more body language involved.

My thing is though, I am a mechanic, work on cars 5 days a week. When I want to go out and ride I want to ride, not change out pistons and rings or replace shims. Now I know being a Toyota Mechanic, those shim type setups go forever without adjustment. I have never even seen anyone adjust them in the 1.5 years I have been with toyota and that is all the cars come with now.

Sorry for the long post, just expressing some thoughts.

[rowlrag]

Ride it till she starts smokin.;)

[86atc250r]

Sounds like the 450R will work very well for what you're wanting --- just give it routine maintenance and it should provide you with the same longevity (likely better) as your 250R has.