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Discussion Starter #1
So I've been looking for a used dirt bike for a while. I had a CR125 years ago and felt that it was underpowered so I was looking for a 250cc 2 stroke or larger 4 stroke. I decided to go with a 4-stroke becuase I didnt want to deal with top-end rebuilds. So I picked up a pretty clean 2002 CRF450r this past weekend. I was reading through the manual (titled- "owners manual & competion handbook") and see that I'm supposed to change the piston and rings every "3 races or 15 hours". Really?!? I'm not racing this thing. Just riding around on some trails at a cabin my family has and maybe I'll take it to a local motocross track a couple of times a year. Anyone have experience with this bike? How far can I stretch that 15 hours? If I knew I had to rebuild the top end that often I would've went with a 2 stroke.
Do you think it's safe to just ride it until I start losing compression or getting a little smoke out of the exhaust? I have no idea when the old owner last rebiult the top end. Would a compression test give me a good indication?
 

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yea the rebuild of rings is bs. never heard of such a thing witha four stroke. racing or not. Even my race buddy's dont do that to their four strokes, but thats 250's . if you dont mind me asking, what did you get it four. I want to get a 450 and start doing flat track
 

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Discussion Starter #4
Thanks for the info! I paid $2,000 for it. Apparently these things are really maintenance heavy. I bought a 4 stroke because I didnt think I had to worry about top end rebuilds but these things I guess this thing is a true race bike. I wont be putting too many hours on it before the end of the season so I guess I'll rebuid the top end over the winter... but probably end up selling it next year for something that is more of a trail bike.
 

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Discussion Starter #5
Here's a picture. It actually looks pretty good in the picture but after washing it, it looks much better. almost new.
 

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yea the 450's are kind of a race only enduro type of thing. Just a little to big for fun, more of a serious type of bike. That works out for you in some way if you want to change anthing engine wise since you will have it apart. lol Good luck man and enjoy
 

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Yeah bro, the R's are gnarly on upkeep. Better to go with an X model for the riding you described.
 

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x's are pooches r's are race bikes trust me with many years of dirt, id rather rebuild a 2smoke every year than a 4stroke every cpl. i built my first 2stroke afterschool when i was 12. yes splitting the case for the bottom end(cranks rods ect) sucks but top ends take probably an hr(and ya im being honest) 4strokes u have to buy everything thats in the top end on ur car motor chains tensioner pistons rings valves need shimed at least once a season or they will get so tight they wont open and ull be left with a bike that wont start or run. my expirience is racing so yes i ran harder than most would for a hobby. 4strokes make u lazy lol powers ther you can really labor around the track and still hual ass 2smokes you gotta be on it hard and have that thing reved to the moon to go fast. a built 125 2stroke will run with modern race 250f and sound way sweeter doin so. thats my opinion tho. oh and ya i do love 4strokes as well the power curves are awesome especially on the 450f straight up scary at times
 

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I'm not racing this thing. Just riding around on some trails at a cabin my family has and maybe I'll take it to a local motocross track a couple of times a year.
This is what he said he's using it for.....
 

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Discussion Starter #10
I thought the 450r and x basically had the same engine? Oh, well...either way nothing I can do about it now. Haven't had a chance to ride this thing yet. I hear it's fast as f*ck
 

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Discussion Starter #11
How long can I realistically ride this thing on a new top end before I need to worry about a rebuild? The owners manual says 15 hours. I'm sure as hell not doing it that often. I've done some research and it seems like with normal (not racing) use I can get 50-70 hours easy. With the limted amout of riding I'll be doing that'll probably last me a few years.
 

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Keep a eye on your valve specs,we sell more Honda valves and heads because people dont check the specs at normal intervals, keep a eye on your oil level, they don't seem to burn oil they just seem to use it, I had a 2007 CRF250R and that thing was a monster, I can only imagine what a 450 is like.

Keep the oil clean and get a supply of filters, both oil and air, Honda also likes to ship the bikes with the just like a brush stoke of grease on the linkage,steering stem,swing arm,both axles should all be pulled apart and greased,just take a night and get your favorite grease and grease em up,saves you a ton of headaches in the long run,if it didn't have a lot of time on it and if you know the other owner didn't do it,DO IT.

Any thing else just ask.
 

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The piston and rings will probably last you a lot long than that if you take it easy. I actually just got rid of my '03 CRF 450 and it was a great bike. Just make sure to keep an eye on the valve shims. They need to be checked every 10-15 hrs. Also if you want I recommend finding an '05 - '08 head with stainless steel valves. It will bolt right onto your bike and the valves will last a lot longer.
 

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I thought the 450r and x basically had the same engine? Oh, well...either way nothing I can do about it now. Haven't had a chance to ride this thing yet. I hear it's fast as f*ck
I believe the X has a flywheel about twice the weight so it's a lot more foregiving on the tight stuff. I'm sure there are a few other tweaks in there but the basic idea is that the R is for wailing away and going fast and the X is for going a little less fast. I've been wanting the X version for a couple of years but just haven't taken the time to find one.
 

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It'll be alright bro, run good gas in it, keep good oil in it, and ride the piss out of it. Guy down the street from me has a 450r and I swear he rides that thing 5 hours a day, 7 days a week. It's a Honda, it'll only run like **** if you don't ride it.
 

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I changed the top end on my 05 crf450r at about 50hrs. No racing just trails and motocross tracks. It was all still within spec but I would rather replace the parts before it goes bang. By the way I sold that one and got a yz250 smoker. Much easier to work on heaps of fun to ride.
 

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Discussion Starter #17
Thanks for all the replies. I'm going to check the valve clearance this week as well as flush all the fluids and install a new air filter. The bolts on the valve cover look like they were never touched so I doubt anyone has ever checked the clearance...or rebuilt the top end.
 

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Thanks for all the replies. I'm going to check the valve clearance this week as well as flush all the fluids and install a new air filter. The bolts on the valve cover look like they were never touched so I doubt anyone has ever checked the clearance...or rebuilt the top end.
Do yourself a favour and pull the cover and check it. The old crfs are a nightmare on valves. Do a quick google search on it. I love honda as much as anyone but would never buy a older crf. Too many bad reviews to ignore.
 

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Discussion Starter #19
Do yourself a favour and pull the cover and check it. The old crfs are a nightmare on valves. Do a quick google search on it. I love honda as much as anyone but would never buy a older crf. Too many bad reviews to ignore.

I wish I had known earlier..oh well. Should I switch to stainless stell valves...or should i replace the whole cylinder head like buechelr recommended?
As long as the clearances are ok I'm just going to ride the crap out of it for now
 

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you can just switch to SS valves and it will help a lot. I was just recommending the head swap because it only costs about $400 and upgrades the bike significantly both in power and in reliability.
 
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