Jump to content

Yz400F unfixable carb?

Recommended Posts

 

I recently bought an YZ400F, and opened rhe carb and it looked like this: https://m.imgur.com/a/mVg2F

 

The bike started, but with very high idle. Can this be the cause? And is it worth fixing or should i just start looking for a new carb?

 

All answers are appreciated :)

 

Share this post


Link to post
Share on other sites

I would clean your carb really really good and replace all jets and seals that need replaced. Make sure to clean the pilot screw circuit really really good as it has a bend in it and tends to clog up often.

Sent from my SAMSUNG-SM-G890A using ThumperTalk mobile app

Share this post


Link to post
Share on other sites

I dont know if you can see it very well in the picture, but for me it looks like the throttle slide plate is broken. I have checked the engine, and there is no debri in there. And it also looks like it can get air through it easily with that big piece broken off

Sent from my SM-G930F using ThumperTalk mobile app

https://m.imgur.com/a/mVg2F

Woops, linl was broken, hope this works

Sent from my SM-G930F using ThumperTalk mobile app

Share this post


Link to post
Share on other sites
I dont know if you can see it very well in the picture, but for me it looks like the throttle slide plate is broken. I have checked the engine, and there is no debri in there. And it also looks like it can get air through it easily with that big piece broken off

Sent from my SM-G930F using ThumperTalk mobile app


https://m.imgur.com/a/mVg2F

Woops, linl was broken, hope this works

Sent from my SM-G930F using ThumperTalk mobile app




Link didnt work cuz you had a period at the end. Ya at the top off to the right a little bit. If it is broken or cracked replace it. If you want to replace the carb with the same carb it's gonna cost $$.

Sent from my SAMSUNG-SM-G890A using ThumperTalk mobile app

Share this post


Link to post
Share on other sites

How hard is it to change just the slider then? And will it be as good afterwards? I am looking for a new carb, but as i am quite new to this, i dont know how much work everything is. I did look at this: http://www.keihin-fcr.com/index.php?route=product/product&path=111_107&product_id=57 , but dont know if its worth the 475$ + shipping to Norway(usually about 100$+)

Sent from my SM-G930F using ThumperTalk mobile app

Share this post


Link to post
Share on other sites

Fixed post.

New vacuum release plate and seal. Common weak spot in that model year carb. Might also want to get a new pilot jet and ensure the fuel screw is 100% serviceable. I'd do this and not risk buying another guys headache.

The site you linked to is suspect. Some have gotten good stuff from that guy, some garbage. Do not let the name mislead you into thinking it is an authorized dealer, it is a guy in a garage.

Share this post


Link to post
Share on other sites
How hard is it to change just the slider then? And will it be as good afterwards? I am looking for a new carb, but as i am quite new to this, i dont know how much work everything is. I did look at this: http://www.keihin-fcr.com/index.php?route=product/product&path=111_107&product_id=57 , but dont know if its worth the 475$ + shipping to Norway(usually about 100$+)

Sent from my SM-G930F using ThumperTalk mobile app




Change the slide and seal. Clean the shit out of the carb and go from there. It is very easy to do. Shows you In the manual.

Sent from my SAMSUNG-SM-G890A using ThumperTalk mobile app

Share this post


Link to post
Share on other sites

Yup I agree, no need to replace that carb. Buy a manual and the right parts and it will show you step by step on how to take it apart, clean it, and reassembly. Easy peezy lemon squeezy. You will save hundreds of dollars. Go on bikebandit.com for a carb diagram and either order from there or get part numbers.  Clean the crap put of the carb, carb cleaner, compressed air, pipe cleaners, whatever you gotta do, buy a rebuild kit and a new slide and whatever else needs to be ordered. Shouldn't take more than a half day to get her back up in running shape.

Share this post


Link to post
Share on other sites
5 hours ago, Valo said:

Since im kinda new to this, i want to make sure i order the right items. It also takes along time to get it since i live in Norway.

http://www.ebay.com/itm/272685467449

http://www.ebay.com/itm/272686665403

Sent from my SM-G930F using ThumperTalk mobile app
 

That carb rebuild kit is not complete

You need to order by the piece

- slide plate

- slide plate seal

- fuel screw oring

- bowl gasket and orings

- float needle

- new pilot jet

- new hot start cap (get an aluminum one, not the oem plastic)

- accelerator pump upgrade kit      http://www.crfsonly....roducts_id/3932

 

JD Jetting, Jetsrus.com, or Sudco can help you with all but the nut.

Share this post


Link to post
Share on other sites

For cleaning the carb body I’ve had good luck with berryman’s carb cleaner that comes in a 1 gallon bucket. It has a basket. Just don’t leave stuff in there too long. I don’t know what’s in that stuff but pretty sure it’ll eat about anything if you leave it in there too long. It cleaned my carb that had sat in rotten fuel for years without any issues at all. It’s some strong stuff. 

Edited by Schpenxel

Share this post


Link to post
Share on other sites
5 hours ago, Schpenxel said:

For cleaning the carb body I’ve had good luck with berryman’s carb cleaner that comes in a 1 gallon bucket. It has a basket. Just don’t leave stuff in there too long. I don’t know what’s in that stuff but pretty sure it’ll eat about anything if you leave it in there too long. It cleaned my carb that had sat in rotten fuel for years without any issues at all. It’s some strong stuff. 

^ DO NOT DO THIS ^

There is a neoprene split body seal on the FCR carb that will be damaged by diping in real solvent. 

Even if you only dip in for 10 min, the melting of the seal will continue until it's completely deformed.

The only reason to soak an FCR carb is if there is visible green corrosion, or if the check ball in the apump system has corroded/stuck.

Use Simple Green or Pine-sol if you have to soak, and leave it in for a day or two.

The only passage other than the apump system that has a problem is the passage above the pilot jet, which can be reamed with small copper wire.

Share this post


Link to post
Share on other sites

Apologies for the bad advice--It worked for me but sounds like it isn't a great idea and I may have issues down the road because of it.  

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×