I caught another post on this topic but no-one really had an answer...So I figured that some of the 450R owners have by now put at least 100 hours on their machine...So I was wondering if you do have to rebuild the top end after 100 hours...I ask this because I want to get a 450R but if I have to put a new top end in it every 100 hours then thats just crazy...I meen I go on some week long riding trips we're I can easily put 50 hours on the quad and I would hate to think that two of those trips then I would have to have a new top end in it. So whats the deal...

 

I dont see why. The cylinder is coated just like any of the other high end sport models so it should last a LONG time. I havent ever heard of this but who knows.

 

Ya, I don't see this either...I meen if you keep up on the oil changes and keep up on the maintenence then it should last a long long time...I just heard this and was wondering....It would be crazy knowing that after about 6 good weekends of riding I would have to redu the top end..thats crazy.

 

Besides that, its a Honda. I try not to be brand specific but Honda is known for their reliability in every internal combustion engine they make. I have seen Honda cars that were beat to crap, had 500,000 miles but they ran great. Same goes for their power washers, generators, motorcycles, just about anything they make. If it was a 2 stroke then I wouldnt doubt it but being a 4 stroke I would say it is highly doubtful and this is the first I have ever heard of it.

 

I would say 100 hrs. is about right. But, I don't plan on putting the kind of miles on the 450 that I would put on one of the 400's, so this isn't a burning issue for me. This bike probably isn't the best choice for the average rider. You want a bike that will go forever without a rebuild? 400EX!

 

You guys compairing a 450R with another quad (or any other 4 stroke motor) from honda such as the 400EX
is like compairing a street bike like the CBR600 with a car like the civic.

Yes.. they are both 4 cylinder, 4 stroke.
just like the 450 is a single cylinder 4 stroke, as is the 400EX.


The difference is the length of the stroke.
The CBR if taken care of will last a long time... for a street bike. (50, 60K miles is a TON for a street bike)
The Civic will last 300K?

The 400EX will last forever before a rebulild is needed...
the 450R will NOT.

These high performance super short stroke motors in the street bike just wont last as
long as the relaxed motor in the civic... just like the 450R motor wont last
like the relaxed motor in the 400EX.

100HRS before a rebuild? Id be a little surprized if they lasted THAT long.

 

I stop and talk to every CRF450 rider that I meet out on the trail, and believe me, this is a very popular bike, so this has been a large survey! Nobody has rebuilt at less than 100 hrs. But, it IS best to do a rebuild before you have to!

 

Short stroke with a long(er) rod= less side loading on the piston = longer life.
Long stroke with a short(er)= more side loading on the piston = shorter life.
More RPM = shorter life. Less RPM = longer life.
Get lazy on the air filter deal and your engine will be done before your new boots stop hurting.

 

Well said Doc!
If ya'll have ever seen a 450 piston, and notice how short (almost non-existent) the piston skirts are... you'll understand why the 'recomendation'....

It's just like everything else however.... 'they' recomend a rebuild or re-ring a 2 stroke after every race.. Do we all do that? Hardly. How well it's maintained and ridden has alot to do with that equation.

Remember it's WAY cheaper to do a rebuild before it grenades... You think 2 strokes were bad... just wait.

 

top end on r, $140........................ top end on 450r, pricefull! i bet the cams ,valves,and springs are big fu@kin buck$ i love my simple little engine[img]i/expressions/face-icon-small-happy.gif[/img]