still not craking

flooding issues. I've just rebuilt the carbs and put them back on the bike. It won't ignite for more than 5 seconds. each of the spark plugs is wet and black but will produce a clear blue spark. Fuel level in the bowls if good, maybe a little low.

I've set the mixture screws three turns back from closed and messed with them further open and further closed. not much improvement.

Battery is brand new and fully charged.

Any suggestions?

 

I just set my pilot screws using a colortune plug. My carbs are clean and I just installed a new Yamaha paper air filter. My pilot screws are set at about 1 turn open. When I had a new Uni foam filter, the pilot screws were about 1 3/4 open. My bike is fully stock and the float level is set at 2mm. I'm a little nervous about the 1 turn pilot screw setting, but I'm going to ride the bike and check the plugs and see how it runs before going back into the carbs. In any case, I think three open would be very rich.

 

The floats must be off that's the only thing it could be. I don't think you can mix up the jets on Hitachi carbs. If it was the petcock was bad running thru the vac line it would only flood on 1 cyl. I wouldn't think you would have 4 bad needles and seats everything pointing at the floats. Did you set the floats wet? and on the bike only reason i said on the bike was so the angle is correct

 

This sounds to me like you didn't actually wet-set your floats to spec.

Yes you CAN mix up the jets in the Hitachis, Haynes managed to.

You may also have an enrichment plunger or two not fully seating.

 

I'll try a few things and then give the floats another look.

Possibly a dumb question: Is there any chance flooding is caused by a lack of air?

 

Just checked the fuel levels off the bike twice. Spot on.

I did notice that one of my enrichment plunger seats is different than the others. It's on carb 2. The thread portion of the seat is identical to the others, but the "nut" on top is less than half the height of the other three seats. The plunger is the same and since they pull up, I'm not sure how this could cause flooding. Any thoughts?

What else in the carbs could cause the flooding? Jets all look good, 107 on the mains, 36.5 on the pilots.

 

Whoops, the air jets were not consistent. Had the pilot and main jets reversed in at least one of them. And the Haynes manual conflicts with what Chacal wrote. I'm gonna go with Chacal...

 

yep haynes has the air jets reversed

 

Not only is possible to accidently reverse the jets (which is also a COMMON mistake), it is also possible to accidently switch the air jets from the front of the carb with the ones that are under the diaphragm.........another COMMON problem that I've come across.

Also, your idle mix screws should be around 2.5 turns out to start with.....

Dave F

 

Update: switched the jets and now she cranks. Woot!
Still runs like crap, but I'll tune it tomorrow.