How often a new top end?

[Redtail]

Looking at possibly getting a used 450r for xc racing and can't find an answer to my main question. How often will it need a new top end if I'm mainly riding trails and doing an xc race every month or so. I talked to one guy who raced mx on yfz's and said you had to replace it every 15 hours. Thats way to much for me! Are there any other engine maintenances that are specific to the 450's? Thanks

[CJM]

15 hours is just stupidity unless your joe byrd, walker fowler or wimmer or something. They need every last ounce of power and rebuild or swap motoers every few races.

Id say you could get away with 50-75 hours and just do rings/piston and check over everything. Maybe alot more, depends on how you take care of the quad. Me, I ride flat out at least 3x a month for hours on end and I change my stuff at 75-100 hrs after inspection if need be.

[Redtail]

So how much does your repairs typically cost after 75-100 hours? I'm coming off of an 08 trx250ex that I have never had to do any maintenance on at all.

[Logan #34's Dad]

The key to long engine life is keeping the air filter clean...
Change oil and filter frequently also.

[CJM]

So how much does your repairs typically cost after 75-100 hours? I'm coming off of an 08 trx250ex that I have never had to do any maintenance on at all.

Rings are cheap, pistons are about 200 bucks.

[2001400exrida]

The key to long engine life is keeping the air filter clean...
Change oil and filter frequently also.

Dead on!

I just pulled a motor apart from my 450r that had 300-400 hours on it. That thing was clean as could be. The cylinder looks literally brand new, piston and rings were fine and the crank appears to be solid still as well. I ran this quad in the woods for years and then did 1 1/2 TT seasons with it. It had been running a 13:1 piston and a s2 cam. Nobody runs these quads like grandma's so we can all assume we're running them as they're made to run...all out!

Honda suggests inspecting the piston some ridiculous 15 hours or something, but after seeing how well mine looked after hundreds of hours I'd say with proper maintenance these machines can last several hundred hours.

If you drop a radical cam in there you will immediately lose yourself some reliability. Many people think the high compression pistons are what cause these motors to require more maintenance. Fact is, high comp pistons aren't what's hard on crank, radical cams are the hardest things on these motors. Stick with hotcams or a mild web cam and you will be able to run forever.

[Redtail]

Wow, Thanks a lot for the replies. I do believe I will go with a 450 now. I just needed a couple of opinions to reinforce my decision.