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When To Refresh The Engine

4K views 6 replies 5 participants last post by  whirlybird 
#1 ·
I wanted to get your opinion on this. I had a guy get a hold of me who is interested in buying my bike and he is concerned about the milage.

2900 street miles and 2500 track/race miles (one season). I got it at 2900 miles. Oil has been changed after every weekend and still runs as good as the day I picked it up. I've never refreshed anything and the engine is as stock as stock can be.

How often should you be refreshing a stock engine that is used to race/track?
 
#2 · (Edited)
Interestingly, I just had an oil analysis done. They told me that based on the aluminum content in the oil, from the hours of operation I noted since the last change, my engine is going to be pretty tired by the time I get 3000-5000 track miles on it. I think track miles are pretty hard on the 300, while I know most supersport middleweights can go much longer at race pace before needing a rebuild. Those Blackstone oil guys are pretty cool, and I get the feeling they do more race vehicles that road vehicles.

It kind of reminds me of typical motocross engines. A 250 is going to need a rebuild waaay before a 450 needs one.

I'm no expert on it though, because I've never owned a race bike long enough to refresh the engine. My bikes end up wadded up beyond use before the engine is done on it's own. Lol.

edit: On a well used track bike, a compression test could help insure confidence to the buyer.
 
#3 ·
Interestingly, I just had an oil analysis done. They told me that based on the aluminum content in the oil, from the hours of operation I noted since the last change, my engine is going to be pretty tired by the time I get 3000-5000 track miles on it. I think track miles are pretty hard on the 300, while I know most supersport middleweights can go much longer at race pace before needing a rebuild.
Thanks for sharing your oil analysis. I am a bit surprised at the low expected engine life because I always thought that the Ninja 300 engine is not a particularly stressed engine. Considering the on road life of the engine,which is much higher, maybe its the sustained high rpm operation that causes excessive wear. I rev it to 11K every chance I get when upshifting through the gears, but cruise at around 8K rpm. From now on I will do high speed straight line runs sparingly to prolong the service life of my engine.

I do not know anything about track days, but 3000 miles at an average of 80 mph(I am guessing) should mean around 40 hours of track operation- is that good enough for one full season of racing?

Regards,
Kaustav
 
#4 ·
I think it's more along the lines of time spent at full throttle at high rpm. No street bike is going to have that issue, even 300's that see 80 mph all day. Street riders should not be worrying about life expectancies. 50K miles easy on a 300, IMHO.

But like I said, a compression test tells a lot. There's a PSI range in the service manual.
 
#5 ·
Kind of depends on condition, budget and competitiveness.

If there is no smoke, good compression, shifts well, etc and I'm like every other broke racer out there, I would run it till I had a problem. Oil analysis like Zaph has done is a good thing too.

Of course, If I had an endless budget, I would rebuild every season. >:)


Buying a used race bike is always a gamble. Everyone knows it's been rung out, but also, they are generally more well taken care of than your average street bike. The dude is probably just trying to get the price down as much as possible.
 
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