2000 YZ426F will not start


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  • criggs88

Posted August 06, 2015 - 10:21 PM

#1

Hey everyone, first time posting, hoping someone on here can give me a bit of guidance with my YZ426.

 

First an explanation of the situation: This was my dad's bike back in 2004-2005 or so, he bought it from a close family friend who was the original owner. All maintenance was always done on time, the bike was kept in peak condition, as it also was when my dad took ownership of it. Then my dad passed away in 2009, and the bike has sat ever since just gathering dust in the garage. So, I decided that it was time to try and breathe some life back into the ol' YZ, if only for the memories (I have 6 bikes including this one). 

 

First thing I did was take the carb off (the carb was always emptied after each ride since we didn't go out that much, and the bike was stored with no gas), and sprayed through all of the jets and small passages in the bottom and bowl. I originally did not want to remove the float for fear of accidentally changing the float height. Put the carb back, added fresh gas, checked the oil, and gave it a few kicks. I was unable to get the bike to fire up at all. So I pulled the plug and checked it, found it very dirty and worn, so I decided to replace it. After I put the new plug in, I was able to get the bike to fire up with the choke on after 10 kicks or so, but it would immediately die out, no idle whatsoever. So, I figured that maybe I hadn't cleaned the carb well enough. I pulled it off again, this time removed the float and all of the jets. I soaked the jets in cleaner for an hour or so, sprayed carb cleaner through them and the bottom of the carb, then used compressed air to dry everything out. I also disassembled the accelerator pump and cleaned the passages there. I figured this should have been enough, put it back in the bike and tried again. This second time, I was able to get it to fire up with the hot start on after many kicks, but it still would not stay running. Disheartened, I gave up for a while.

 

Well today I decided to give it one more go. User manual and Youtube videos handy, I pulled this carb as far apart as I could (the only thing I didn't remove was the slide assembly), soaked the bowl and jets in cleaner (again), and sprayed 2 full cans of carb cleaner through everything. This time, I noticed that the accelerator pump diaphragm had a few small tears on the underside of it, but they hadn't gone all the way through. I also noticed that the gaskets and o-rings were in really bad shape. I got everything as clean as possible, put it back together hoping that this was enough to at least hear it fire up and run somewhat, and kicked it over. Still nothing. Now, I can't get it to start on any setting, which makes no sense. It seems that the more I've cleaned this carb, the worse it has gotten. I don't feel that I have done anything wrong as far as cleaning/assembly, as I've cleaned/rebuilt/set up many other carburetors just fine before. However this is the only flatslide I have ever worked on.

 

So anyway, I have a couple of questions:

- Is there something I could be missing here that is specific to this bike? I have been doing internet searches all day and haven't really found anything specific.

- What accelerator pump kit do I need for this bike? I checked the parts diagram/lists that are up on this site, and it shows 4 or so different part numbers. I read on here that there are different options for it, but as far as I know it has the stock one in it right now, so how do I know which one that is?

- Originally I checked for spark, which it had, and assumed that timing and all that was in order since the only thing between now and this bike running perfectly before is about 6 years. Is there something else I should be checking? I am going to re-check for spark this weekend, but I feel like if the bike fired up a few times spark should be fine...

 

Anyway, thanks for reading, I appreciate any help that you guys have to offer. I'd really like to get this bike back in decent condition again, so anything and everything helps.







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