Need some 426 help

Check the stator output when hot. Also go through it and clean all electrical connections and apply dielectric grease to maintain good connectivity. Also check TPS

Compression testers are fairly useless with auto decompression engines and that's why no specification is published in the manual. Have a leak down test done instead.

I have to pull the lever to decompress, so I don't auto decompress do I? Either way I don't feel like I lose compression when I kick it when it is dead anyway. I'll research the leak down test.

Even with manual decompression, Yamaha did not publish compression figures. A good compression test would require that you crank the engine through several complete compression strokes, which in a healthy 426 is practically impossible.

I built my own leak down tester. Pretty sure I got the idea from someone on TT, but if you would like I can try to send you some pictures. It was pretty easy thought, I used a brass fitting, an old spark plug, a flexible grease hose, and a quick connect air hose fitting.

Ya that would be sweet. PM it if you can.

Looks like I am going to get my hands on that 2002 426, so this current problem is going to be put on the back burner for now.

But I started a new thread about how I could combine the 2000 and the 2002. Thanks for all your help on this one. Thanks in advance for any help on the new question, it's a bit easier too. Here is the new thread:

Well, I've taken off my bike:

handle bars

both tires

rear brake res.


clutch case cover

fly wheel case cover

both radiators

full plastics


And fixed:

Muffler basically hanging off

rear brake

changed oil (first time??? ouch...)

air filter change (again, first time?)

Now I just hope the neglect of the previous owner doesn't cause the bike to die on the first ride after I've put all this work into it.

As for the 2000, I'm going to basically get it put back together with spare parts and limp it into the shop and have them tear it apart and see if it's even worth fixing once they get it diagnosed.

thanks for all the suggestions guys.

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