QUOTE="woodrow wilson, post: 738897, member: 19963"]Thats crazy every 15 hours but I guess If your racing its the right thing to do!! Little as we ride 15 hours would be 3 years. .lol..
If you read the shop manual for both Honda and Yamaha both state 15 hrs. This is for the race model 450 Rs. The reason is the piston skirts on both are only about an 1 or so long .Now consider the cost to build one since parts are so high for rods ,piston,valves and port work, right Wifesblaster ? Now add 12:1 compression ,race gas and 60 + hp they need more maintence. Those that race know this , because when they blow they take out the top and bottom end together ! Those that play race and ride don't and end up selling the quad instead when it blows. The rings and high lift cams get pounded when they turn 9,000 -10,000 + rpm.
How do I know any of this ? Our Honda shop sponsored Candace Lees National race winning Honda 450R. It had special valves, springs and cam made by HRC, trying a stock piston/ rings at first, then switching a Venolia forged one to survive. Still.. Every 3 races it was torn down and refreshed.Its not just the race time on a motor ,the practice time has to be figured in too.[/QUOTE]
I understand that the shop manual says rebuild every 15 hours. I think it's different when trail/play riding. If I went on a 3 day riding trip and rode 5 hours each day I would need to rebuild it? Saying you have to replace the piston before it due for a spark plug change or valve shim is absolutely crazy. I can assure you I'll get over 100 hours out of this build. The reason is +1 upgraded valves, heavy valve springs, long rod stroker, and cp piston. All of the best parts are being used for power/reliability (I know there's a fine line there). The long rod will help with rod angle, hence less stress on the piston skirt. And I will be running 13.5 to 1 compression. Getting 3 or 4 years out of a top end on these bikes is very common. I don't know where Honda came up with the 15 hour inspect/replace.
Take modern motor oil for example.... Why are we still being told to change our oil every 3,000 miles? With the introduction of synthetic oil and everything we have learned about oil, heat, and friction we should be able to get more than 3,000 miles, right? I change mine every 5,000 or 6,000 if I'm lazy!
I have never really payed very close attention to the maintnance time frame that is outlined in any manual, if I did I would be broke!!!! I know enough about bikes to know when they need and to look for the signs that tell me when they need it.
How many unsponsored riders actually overhaul their motor after 15 hours of use. I bet they are few and far between!
