I am a current owner of an 03 400EX and was considering upgrading to an 06 TRX 450R. However, after searching around the internet I have come across several issues on motor longevity. Some places say the top end of the motor must be rebuilt every 100hrs, which is hard for me to believe. But, I also understand that this 100hrs also probably pertains to racing 450R's. So my question is this, does the top end of the motor really have to rebuilt every 100 hours? Has anyone here had one the ATV's for a while and logged any considerable time on the motor? Are there any other issues with the 450R? Thanks for the input.

 

i think it's the fact that the engine is made for all-out racing, not 20 years of trail riding. Most race engines get rebuilt after the race, so they dont need to last that long. I'm not bashing the 450r, its probably a great machine, but i would not buy one because they are not set up for the long haul.

 

Initially, there was some speculation (based on the dirt bike engine) that the engine would need frequent rebuilds, but I don't think that has been most peoples experience. In fact, my several friends with the dirt bike have not needed frequents rebuilds either. I can't testify personally however, because I don't have 100 hrs. on mine yet.

 

If you install the HRC kit, plan on replacing your piston and rings every 15 hours/12 races.

Piston pin every other time.

 

Im not trying to question your knowledge, but are you sure that is accurate? I don't even open up the motor on my 250R that often.

 

My KX500 hasnt been opened up in years and years.. literally.
(and runs SO strong)

1bad250R, that is a killer truck your dad has.

 

All I am saying is what is printed in the HRC Set Up Manual that comes with the racer kit.

Sorry if I came across as a dick, did not want too.

The TRX450R with the HRC kit is a deady serious race machine, IMO.

12:1 compression, stock, the whole 9 yards.

Sure, the piston might go longer.

I really do not know until we have several in actual use.

I do know that the earlier versions have proven extremely reliable, I see no reason this one would not be as well.

Other than the fact IT IS TOTALLY RADICAL in it's specifications and performance!

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Most of the issues I've seen and heard of are valve and head problems...due to over-revving to often(riding on the limiter)

 

You know what - I am going to study that power curve and may want to leave the lower RPM limiter in place to assure longevity -
???

 

Worse than the RPM itself would be riding the limiter...you know this guy...he's the one going up a sand dune and just leaves it on the limiter rather than shift...or he's the guy who has bad body position before take off and is winding up the bike to much to compensate(this guy is usually a 2 stroke convert)