[Jonesy]

these are straight off gt thunders website

  Below are 3 links to comparison runs made on the dyno comparing the TRX450R to the YFZ450. Both bikes were stock, both bikes had about the same amount of breakin time, both bikes were dynoed under the same conditions including 30MPH air blowing across the bike. Interesting thing with the Honda was the ignition was going into a double spark condition at 8400 rpm. The Honda was hitting the rev limiter at 9200 rpm, however on the runs below you will see the graph for the honda stop at 8400 rpm on all the runs that are based on rpm. You can see the full spread on the run that is speed based. In all the graphs - the blue is the YFZ and the red is the TRX.[/b]

Red = stock 450R
Blue = stock yfz450

HP vs RPM

Torque vs RPM

HP vs. MPH

 

[TrX450rKiD]

I've seen these before and no one has been able to explain what double-spark condition is...???

 

[Jonesy]

My only guess would that it is sparking twice instead of once.

Anyone else have the right answer and why this happens at all?

 

[TRX450rlude]

Originally posted by TrX450rKiD@Mar 29 2004, 04:34 PM
I've seen these before and no one has been able to explain what double-spark condition is...???

the double spark thing is only for better emmisions. It sparks one time for normal fire of piston, then it fires again when it does not need to. It does that to burn off any extra air/fuel that may still be in the chamber, so when its sucked out the exhaust it comes out cleaner.....Honda is the shiznit. ...you can say this with a bunch of technical words...but this is what it means.

 

[Jibrille]

I think I've seen these posted at yfzcentral.com

Very cool though, B)

 

[TRX450rlude]

Originally posted by Jibrille@Mar 29 2004, 11:23 PM
I think I've seen these posted at yfzcentral.com

Very cool though,  B)

thats funny, because the first one shows that the R has more horsepower through out the entire power band. the YFZ peaks out with 1 more horsepower at the end of the power band....how often do you need that.....not to mention the fact that it shows the TRX with way more torque and top speed....yet YFZ people posted them like they showed the YFZ with the advantage...that cracks me up... :lol: :lol: :lol: :lol:

 

[joe1l]

The thing with the YFZ is that it is geared MUCH lower than the TRX, hence they get good take offs. The other thing is the YFZ will rev a little more, which will keep thier top speed up. <_< The other thing I seem to understand is that the stock Yamaha exhaust is very restrictive, holding back quite a bit of power, so the power improves quite a bit. The higher compression piston, combined with the extra little revs is really the yamaha's advantage. These are very easy fixes for the TRX luckily. It ultimately will mostly depend on the rider when comes to it.

 

[Jibrille]

Damn I can't wait for my 450R

 

[TRX450rlude]

Originally posted by joe1l@Mar 30 2004, 01:12 AM
The thing with the YFZ is that it is geared MUCH lower than the TRX, hence they get good take offs.  The other thing is the YFZ will rev a little more, which will keep thier top speed up. <_< The other thing I seem to understand is that the stock Yamaha exhaust is very restrictive, holding back quite a bit of power, so the power improves quite a bit.  The higher compression piston, combined with the extra little revs is really the yamaha's advantage.  These are very easy fixes for the TRX luckily.  It ultimately will mostly depend on the rider when comes to it.

the other advantage is the DOHC. although this unicam thing is alright, I would rather have 2 cams and a half of pound more up top...this thing would rev alot faster with 2 cams.

 

[Schmitthead]

its not just the 2 cam but also 5 valve. titanium valves at that. its a lot more efficient

 

[TRX450rlude]

Originally posted by Schmitthead@Mar 30 2004, 07:21 PM
its not just the 2 cam but also 5 valve. titanium valves at that. its a lot more efficient

so Honda accomplished what Yamaha did with alot less technology....funny

 

[TrX450rKiD]

Originally posted by Schmitthead@Mar 30 2004, 07:21 PM
its not just the 2 cam but also 5 valve. titanium valves at that. its a lot more efficient

the tit. valves wear down MUCH faster though...thats why Honda went the other way...honda quality

 

[TRX450rlude]

Originally posted by TrX450rKiD+Mar 30 2004, 07:41 PM-->

<!--QuoteBegin-Schmitthead

@Mar 30 2004, 07:21 PM
its not just the 2 cam but also 5 valve. titanium valves at that. its a lot more efficient

the tit. valves wear down MUCH faster though...thats why Honda went the other way...honda quality [/b]

and its still just as fast.

 

[Schmitthead]

there is no replacement for displacement

 

[TrX450rKiD]

Originally posted by Schmitthead@Mar 30 2004, 07:43 PM
there is no replacement for displacement

I like that saying...but look at the Raptor! I say there is no replacement for technology and quality

 

[Jibrille]

Originally posted by Schmitthead@Mar 30 2004, 06:21 PM
its not just the 2 cam but also 5 valve. titanium valves at that. its a lot more efficient

I think there was something posted on yfzcentral about the 4 valve 5 valve thing. They were talking about how the 5 valve set up doesn't really give it any more of an advantage. The valves intake and exhaust added up to the 450R having a bigger mm or something letting more in and out.

It started as a 450R bashing thread, though a lot of the YFZ guys aren't as biased as some think.