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wfo4rv
04-22-2013, 07:17 PM
after how many hours should a full race engine be rebuild. 14:1 comp. engine. I was told 10 hours and i think theres no freakin way!
BlaineKaiser450
04-22-2013, 08:22 PM
On my 04 trx450r I had over 350 hours when the bottom end finally blew. It was a 12.5:1 with a hotcam, stock head, and the crank bearing was updated. Not really a full race motor, but I thought it was remarkably reliable. I doubt many would last as long as that one though haha I would rebuild it every 25-30 hours just to be safe if its a full race motor used ONLY in race conditions, which mine wasn't.
LITE
04-22-2013, 08:25 PM
Having been a mechanic for a factory race team for many years. these full race mx engines are being rebuilt after each race., that adds up to about 4 to 5 hrs.
And start out new again for the forth race . Not cheap to be fast and reliable too.
LITE
04-22-2013, 08:25 PM
Having been a mechanic for a factory race team for many years. these full race mx engines are being rebuilt after each race., that adds up to about 4 to 5 hrs.
And start out new again for the forth race . Not cheap to be fast and reliable too.
01boneless
04-22-2013, 09:34 PM
keep oil changed every 5-6 hrs or so clean filter every ride (foam) and you should be good all season. i rebuild mine in the winter and run it all season and its never really needed rebuilt but i do it anyways....last year had 75hrs i run it hard on the track and its fully built.
trick450r
04-23-2013, 05:58 PM
What defines a "race motor" is quite variable. If it means anything to you ive got a full dasa motor and it would go through an entire season before a rebuild, only actually popped on me once. After I stopped racing we put a second base gasket on to pull the compression down a bit (was around 15:1), its got to have 80hrs on it now and runs like an animal. Keep up on your maintenance like your life depends on it and it'll go longer than you think.


To the gentleman who mention the factory race teams: I agree that the motors get changed every race, but only because its a potential weak link. Clearly they will run longer than an hour.
wfo4rv
04-23-2013, 06:10 PM
I'm just having issues with my zuk and wondering what it could be . It has 12 hours on it but shows symptoms of needing top end