Mikuni BN-38 Questions

[advacomp]

Can anyone tell me what to torque the cover screws on a Mikuni BN-38 to? I have looked everywhere and can't find the torque, nothing in my service manual and qstorms guide says to torque to spec.

Also do I need to torque down the screws for the check valve housing? I had to use an impact driver to get them out so I'm assuming I should use it to tighten them back down?

Should I use blue loctite on all these screws?

Is it ok to replace the phillips head cover screws with bolts?

Is it ok to use a thread chaser on these to clean out the aluminum rust and old loctite?

Should I be using seadoo lube, sealant, oil, or nothing to apply the new o-rings and gaskets? Anything on the paper diaphrams?

What should I use to scrub off the old corrosion from my carbs? I tried carb cleaner and a toothbrush but no luck, didn't want to try anything else in fear of scratching the metal.

If I soak my carbs in a bucket of carb cleaner do I need to remove the choke and throttle shafts?

Sorry for all the newb questions, this is my first ever rebuild and I've searched all over these forums but can't find an answer (or a direct one) to any of these questions.

 

[Dr Honda]

Can anyone tell me what to torque the cover screws on a Mikuni BN-38 to? I have looked everywhere and can't find the torque, nothing in my service manual and qstorms guide says to torque to spec.

Also do I need to torque down the screws for the check valve housing? I had to use an impact driver to get them out so I'm assuming I should use it to tighten them back down?

Just snug them up.

Should I use blue loctite on all these screws?

If you want, but I don't since they are a bastard to get out.

Is it ok to replace the phillips head cover screws with bolts?

The external cover? Sure... use what you want. I like socket, cap head bolts. Internal, you can sue flat head, counter sunk socket heads.

Is it ok to use a thread chaser on these to clean out the aluminum rust and old loctite?

Sure. Just do it before the cleaning to make sure the junk gets cleaned away.

Should I be using seadoo lube, sealant, oil, or nothing to apply the new o-rings and gaskets? Anything on the paper diaphrams?

Nope. Put them in dry.

What should I use to scrub off the old corrosion from my carbs? I tried carb cleaner and a toothbrush but no luck, didn't want to try anything else in fear of scratching the metal.

Depends where. If it's in an open section... you can scrape it clean with a screwdriver, or stainless bristle brush. If it's in a place like the pump valve faces... then you may have to cut them flat. If you scar some parts... you may mess it up. A brass brush bay help in those spots.

If I soak my carbs in a bucket of carb cleaner do I need to remove the choke and throttle shafts?

Depends on what you are soking it in. If it's not safe for plastic parts... make sure there aren't any going in the cleaner.

Sorry for all the newb questions, this is my first ever rebuild and I've searched all over these forums but can't find an answer (or a direct one) to any of these questions.

No Probs. :thumbsup:

 

[advacomp]

Thanks for the quick reply Dr Honda, your a life saver!

You said to put in all the new gaskets and o-rings in dry, should I still be applying oil to the o-ring for the seats like qstorms instructions say?

I was going to soak my parts in a gallon of carb cleaner that I got at autozone, but its not safe for plastic and rubber and I stripped the screws on the choke shaft trying to get it out so I'll just clean them good by hand. Any recommendations on how to get the screws out of the shaft without damaging it?

Anything I should know about repainting my carbs? I figured just tape off any openings and then hit it with a can of black spray paint?

Attached is pictures of the corrosion I cant get off with carb cleaner. Not sure what you meant by open section?

Thanks again for all the help!

 

[Dr Honda]

They look pretty good to me.

"open sections"... like in the pump body. you can scrap them, and nothing will get damaged

What shaft are you talking about. (removing the screws)

Paint: Yep... just mask the top, bottom, and the nipples, and spry it.

If you want to coat the rubber parts in 2-stroke oil before assembly... go right ahead. (I normally don't)