YFZ Central banner

1 - 20 of 30 Posts

·
Registered
Joined
·
194 Posts
Discussion Starter #1
This is my step by step of how to retard the exhaust camshaft timing. From the factory, the exhaust cam is advanced one tooth, as compared to the exhauast cam timing on the dirtbike YZ450F. Its not hard to do at all, and the outcome is worth it. Good power gains, and I think it feels like its got better lowend power. It also sounds quiter, too.
Now, along with this mod, I recommend that you should be removing your air box lid, and spark arrester also.
You will have to play around with the jetting after, but again, its well worth the hassle!!!!



First thing to do is WASH THE QUAD!!!!!! Get the engine very clean!!!
Yah, yah, yah I know, my machine looks dirty in the first couple of pictures, but I started to do the pictures for removing the plastics, then I washed the rest of it before takeing the motor apart!!!!!!

Then



































Now your done!!!! You now have the same cam timing specs as the YZ450F dirt bike!

Wasnt to hard now, was it???
 

·
Premium Member
Joined
·
1,214 Posts
Wanted to be the first to thank you for your time and effort for putting together such a detailed how to. Thanks for the Info :D :D :D :D
 

·
Registered
Joined
·
625 Posts
spot on step by step. Took me about an hour from starting to remove the plastics to starting it up to make sure it runs. Thanx Paul that was a great service you did us all.
Isaac
 

·
Registered
Joined
·
197 Posts
you are the man, i'm now going to tackle this task tomorrow with confidence, i was really scetchy about doing this on my own even though i am really mechanicly inclined i usually screw something up, thanks i appreciate it alot, your the man
 

·
Registered
Joined
·
11 Posts
Nice write up. :)

Do you lose any oil when pulling the plug for the flywheel nut?
 

·
Registered
Joined
·
194 Posts
Discussion Starter #6
Thanks for the compliments guys!!!


No, you dont lose any oil, in any step of the mod.
 

·
Registered
Joined
·
2,092 Posts
Anyone that has done this mod have any problems starting it up warm after doing this mod? I had heard reports that doing this mess's up the decompression. I do not know if this is true. Anyone have any problems starting the YFZ hot after messing with the cam? Heard a few guys say that after they messed with the cam they think it messed with its automatic decompression.
 

·
Registered
Joined
·
194 Posts
Discussion Starter #10
I have had ZERO problems starting mine, hot or cold, it fires right up!!!!

They are probally having problems due to jetting issues, if a motor is lean, it wont like to start easy after its hot.
Doing this mod requires rejetting, period!!

Im just quessing here, but thats what I would think the problem is.
 

·
Registered
Joined
·
634 Posts
Hello.

I would just like to add one important fact when doing the cam mod.

two things actually. when putting the top back on you need a gasket (yama gasket) sealer and you need to wipe the oil off the edge with break cleaner before you seal the gasket, and the other thing is the MOON CIRCLIPS.

make sure you put the moon circlips BACK THE SAME WAY!
one side is SHARP and the other edge is ROUND if you put the circlip on 180 degrees and close up your motor, your motor wont last too long.

so as you remove them make sure you put them down on a counter facing the same way so you can put them back right a way the same direction.

otherwise that is a really good page to tell you how to do the mod.
good pics too.
 

·
Registered
Joined
·
625 Posts
I cannot get the pics up ,please help.


Geoff
 

·
Registered
Joined
·
625 Posts
A big thankyou from down under to all concerned.

Great job. :yfz :yfz :yfz :yfz

Geoff
 

·
Registered
Joined
·
625 Posts
Now how do you do it to a blue one? :blah :blah :blah

Geoff.
 

·
Registered
Joined
·
1,073 Posts
Originally posted by Aussiequadrider@Jul 29 2003, 06:11 PM
Now how do you do it to a blue one? :blah :blah :blah

Geoff.
:lol :lol :lol :lol .......
 

·
Registered
Joined
·
30 Posts
Originally posted by daddogrider@Jul 29 2003, 01:13 AM


make sure you put the moon circlips BACK THE SAME WAY!
one side is SHARP and the other edge is ROUND if you put the circlip on 180 degrees and close up your motor, your motor wont last too long.

so as you remove them make sure you put them down on a counter facing the same way so you can put them back right a way the same direction.

Those circlips look the same? I have ask around and other say it doesn't matter which way they go?

What part of the clip do you look at ? I pulled my circlip out without looking ! So how do I tell which way they go ?


It seems all they do is keep the cam from walking side to side,does the service manual help with this problem ?

Thanks

Jim
 

·
Registered
Joined
·
30 Posts
I just got off the phone with a major builder and he said the clips do not have a certian direction! They must be placed in the groove! Your post made me worry for nothing !

Jim
 
1 - 20 of 30 Posts
Top