New Project Bike: '99 YZ400f

[bwdmax]

If you don't get a response try moving the intake cam one tooth CCW. The intake is retarded right now and may still be open when the piston starts back up on compression stroke pushing part of the air fuel charge back into the intake/ carb. Just be sure and roll it through by hand after the change with the plug out to check for any tight spots.

 

[RoverT]

I just pulled the plug so I could feel the engine by hand. It's not easy to turn by any means but I can make it turn by hand, and I don't feel any irregular tight zones.

I'm thinking this might be fuel related. When I cleaned the carb, I just went through the Jets and accelerator pump. Maybe there's some blockage in the body of it. I'll do some testing and/or cleaning to see if it's fuel related.

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[Aspear]

Any update.

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[RoverT]

Any update.

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Been busy with school. Haven't been able to work on it since winter break :/

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[thrill-billy85]

That's an FCR carb, you GOTTA clear out the passages in the body.

Hold off on cam timing for just a minute, or three more months.

My first piece of advice would be (same as BWD) to try a small amount of starting fluid or carb cleaner and see if it'll start and run for a second. If so, it's absolutely a fueling problem. Or carb problem. FCRs are finicky piece. The vacuum release plate on the slide can be installed wrong, the passages in the carb can clog. The air jets in the bell could be clogged etc etc.

Google "how to rebuild an FCR carb" and follow those steps.

 

[RoverT]

Fyi I sold the bike.

Also, yes I know about fcr carbs, I went through a lot of learning to clear up the AP nozzle on my crf.

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