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Author Topic: looking for a yfz  (Read 3069 times)

Offline xTHUNDERCATx

looking for a yfz
« on: June 10, 2014, 12:52:08 PM »
I'm throwing around the idea of adding a YFZ 450 to my collection (that electric start has been tempting me for a while). Something for a decent back up bike but I figured I would jump on here to see if anyone knows of any major issues that came up with any of the years or anything that has a bad reputation I need to be watching for.

Offline JesseA420

looking for a yfz
« Reply #1 on: June 10, 2014, 02:44:12 PM »
early years had to have the oil mod done to cool the bottom of the piston. lots of issues with the throttle over ride system and throttle position sensor also, although those can just be taken off.
Quote from: Hawaiiysr;66760
Yup i sucked the head. taste like dirt.

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Offline JoePA

looking for a yfz
« Reply #2 on: June 10, 2014, 03:45:38 PM »
We raced an 04, still racing it, since 2007. No oil mod done, no throttle issues and I do all the servicing on it year after year and the valves are in spec each and every time. I don't know if we got lucky or what but it flat out rips, gets the holeshot every time and it's a bone stock engine other than the cam mod. If you set the carb up properly with no stupid zip tie mod and jet it properly it never has a bog issue....ever. Key is the leak jet and needle. They are dirt cheap to find and parts are almost as easy if not easier than finding honda parts. If you do decide to get one find an 07 and up as it does have the oil mod done and the suspension on the rear is a little better.

Offline PORTED R

looking for a yfz
« Reply #3 on: June 10, 2014, 10:20:53 PM »
My dad has the 07 and it runs well with just a pipe and intake
Plenty of torque ,recently dropped a few teeth in the rear for a lil more speed
McCoy ProX 350 5mil Duner
McCoys Performance -1-530-476-2222

Offline pinned250r

looking for a yfz
« Reply #4 on: June 11, 2014, 09:19:38 AM »
[MENTION=66]bholzgen[/MENTION] what yr was racer Dave's? 04? Cuz that thing ripped as bone stock. Almost 330r fast.
I ride PINNED! Therefore, no bdt in this household.

Offline Flyin_250r

looking for a yfz
« Reply #5 on: June 11, 2014, 11:01:51 AM »
Get a yzf hybrid instead! Lol

Offline xTHUNDERCATx

looking for a yfz
« Reply #6 on: June 12, 2014, 08:36:46 PM »
Alrighty so i picked up an 06. Heres the current situation when i went to look it fired right up initially it would bog hard if i revved it quickly (had to be eased on) I was test riding it opened it up and she died and wouldnt fire back up, decided to gamble and bring it home anyways for a better price. I pulled the carb and it had a clogged pilot and was layered with yellow gunk (bike sat for a while according to him) i got new fuel in it and she fired up today.  i had it idling for a minute when i blipped the throttle. It bogged like it did initially, back fired and shut down now she wont fire up. What are some thoughts, im going to replace the plug tomorrow, if it has good spark im guessing for some reason it isnt getting fuel but i am not competent at all with a 4 stroke motor some im looking for other possibilities.

Offline Powderillusions

looking for a yfz
« Reply #7 on: June 12, 2014, 09:42:22 PM »
yellow gunk sounds like the fuel was starting to varnish from sitting a long time not being run---if thats the case you need to go through the entire fuel system and clean it out

Just in case you dont already know you have to remove the fuel tank to change the spark plug which is a simple task on the yfz

Offline PORTED R

looking for a yfz
« Reply #8 on: June 12, 2014, 09:45:10 PM »
My uncle had the same problem with his 06 yfz
Owner before him ran 87 octane instead of 91
Ran like crap
,cleaned the carb,changed the spark plug and put fresh 91 in and ran awesome
McCoy ProX 350 5mil Duner
McCoys Performance -1-530-476-2222

Offline xTHUNDERCATx

looking for a yfz
« Reply #9 on: June 12, 2014, 10:18:49 PM »
I spent a few hours today with a tooth brush and break cleaner cleaning the carb it wasn't just left powderillusions mybbad for not mentioning that hopefully that's the case an I'd be a happy camper

Offline Powderillusions

looking for a yfz
« Reply #10 on: June 12, 2014, 10:40:13 PM »
might check the petcock make sure its flowing--

Offline xTHUNDERCATx

looking for a yfz
« Reply #11 on: June 12, 2014, 11:33:48 PM »
i know im getting some kind of flow its filling the bowl up but ill go ahead and give it a check in the morning

Offline xTHUNDERCATx

looking for a yfz
« Reply #12 on: June 13, 2014, 12:23:56 PM »
K so I swapped the plug this morning there was good spark and it fired up. Blipped the throttle and she shut down so I pulled the plug and there is no more spark  I bypassed the tors last night. So what ever is happening is killing the spark

Offline pinned250r

looking for a yfz
« Reply #13 on: June 13, 2014, 01:03:58 PM »
What about the rev limiter box (im clueless to what its called), but i have heard crazy issues about that. ANd i actually had an issue similiar to this with a raptor i had and i had a similiar issue and i replaced the rev limiter, and bingo.
I ride PINNED! Therefore, no bdt in this household.

Offline xTHUNDERCATx

looking for a yfz
« Reply #14 on: June 13, 2014, 01:16:43 PM »
I'm heading to buy an ohm reader now so I can start trouble shooting