OK, I am clear on what to do and the torque specs when going back together after retarding the cam on the yfz450 but - does anyone know whether it should be jetted? Do the valves need adjusted once retarded? Or is this all just adjust and go . . .

Thanks in advance for any help. The bike is BONE stock and I want to modify in baby steps lol. It's my brothers and he's not ready to purchase pipe yet.

Dave

 

Not sure if you * have* to but you can probably stand to jet up a bit. 165/45 will make it run a lot better. They are pretty corked up from the factory.

 

The above suggestions on jetting are good if he's going to leave it stock.

He REALLY needs to add a pipe. And an air filter. (at least remove the lid).
YOu can get a nice DR D pipe for around 250.00 shipped.

After doing this, bump up the main to a 172, get a 45 pilot, put the stock needle on the 5th-6th clip position, and turn the fuel screw out to about 2 1/2 turns out.

You and he won't BELIEVE the difference in torque and HP after doing these simple mods!![img]i/expressions/face-icon-small-shocked.gif[/img]

 

Ok so far I have removed the box lid and taken out the baffle/spark arrester. The stock needle had only one position??? This is an 06. So I bought the YZF needle and put it on the 5th slot with a 17 main jet, 45 pilot jet and so far have left the fuel/air screw alone. The bike rips! Gonna do the cam on Monday or Tuesday - should it be jetted even more once cam has been retarded?

Thanks for any help!
Dave

 

I was wondering if it was an 06 LOL! Yeah, the needle on those is non-adjustable. You did good by getting the YZF needle. You could have also gotten the 05/04 YFZ needle and put it on the 5th-6th clip osition and been good too.

I have heard that some people have had to richen up the pilot by one size (48) when they did the cam mod due to hard strarting issues. Foe me, I never had to go past a 45 pilot, but I also have my fuel screw adjusted out to about 2 1/2 turns out.

BTW, you cannot access the fuel screw on the 06 unless you drill a hole out to access it (or so I have been told). If it is hard starting after the cam mod, try bumping up the pilot another size.

BE VERY CAREFUL when doing the cam mod. There are several step by step instructions with pics out there. There are a LOT of places where a guy can go wrong, so TAKE IT SLOW and be CAREFUL!!

When done correctly though, you should notice a slight increase in midrange and top-end pull! Those YFZs really rip when jetted correctly!! [img]i/expressions/face-icon-small-happy.gif[/img]