New to the YFZ's

[Lquad71]

So my buddy picked up two bikes yesterday but i will be doing most of the work on them.
Ive only been honda until now so i was wondering if there is anything i need to look for or any common problems with 04 and 05 yfz450's. Any input is appreciated because i know every bike has something wrong with them and i was checking so find out if anyone has any good hints, tips, and cautions that could be shared. Thanks again!

[XCRacer236]

Biggest thing with those is the electrical and oil squirter.

If I remember right if the headlights were removed the system wouldn't charge efficiently so the battery would go dead.

The oil squirter allows oil to be directly injected into the bottom of the piston (IIRC) to allow more efficient lubrication. The cases can be taken apart and drilled for this. There's a big write up on it over on YFZ Central.

A lot of people will convert the rear suspension to 06+ to gain the eccentric chain adjustment and better geometry as well.

I could be wrong on some stuff, so don't take all that to heart, but hopefully that will at least get you started.

Originally posted by XCRacer236
Biggest thing with those is the electrical and oil squirter.

If I remember right if the headlights were removed the system wouldn't charge efficiently so the battery would go dead.

The oil squirter allows oil to be directly injected into the bottom of the piston (IIRC) to allow more efficient lubrication. The cases can be taken apart and drilled for this. There's a big write up on it over on YFZ Central.

A lot of people will convert the rear suspension to 06+ to gain the eccentric chain adjustment and better geometry as well.

I could be wrong on some stuff, so don't take all that to heart, but hopefully that will at least get you started.

Pretty good for that XCRacer236!

Another thing we come across with EVERY Yamaha unless its been fixed is the YamaBOG. i.e Stab the throttle and it "Bogs" but then comes right back. Most do it. You can get this fixed by boring the carb out. There are companies that do this and do a great job.

Thats just another thing to add to your thread.

Hope this helps

[maxamillion]

there is a decompression block off on the 04 cylinder head made of plastic that will blow out causing an oily mess. upgrade to an aftermarket billet block off and ur problem is solved

[TOPshelfYFZ]

Originally posted by maxamillion
there is a decompression block off on the 04 cylinder head made of plastic that will blow out causing an oily mess. upgrade to an aftermarket billet block off and ur problem is solved
Got one for sale if ya want it. New in package red anodized.

[jjyfz]

Originally posted by SnyderMS
Pretty good for that XCRacer236!

Another thing we come across with EVERY Yamaha unless its been fixed is the YamaBOG. i.e Stab the throttle and it "Bogs" but then comes right back. Most do it. You can get this fixed by boring the carb out. There are companies that do this and do a great job.

Thats just another thing to add to your thread.

Hope this helps

if one is tuned right and a few other adjustments you can fix the bog. boring the carb wont fix it, a good mod but the bog isnt fixed buy this!

We have had our carbs sent out to companies (wont name them) and the bog HAS been deleted. Yes with tuning and some other mods it can be deleted as well but if by boring the carb it helps the bog (which we have seen this done) why not do so and get more power along with the better throttle response?

[250r4life]

The Boyesen quickshot got rid of my bog.

[bearball12]

Also the bolts back out by the gear for the starter. Pull out the bolts, blue loctite them and tighten them back up. Make sure to get the oil squiter issue taken care of. The seats on the 04-05 are really hard also.