Topic: 1978 CB750 GAS TANK AND CARB CLEANOUT QUESTIONS

[TimK]

Here are couple more photos; float bowl varnish, gas tank (first peek), master cylinder (it was like an oily sawdust).

It was gummed up pretty good.  I dropped the master cyl into a container of vinegar and it cleaned up to some degree.  I need to find c-clip pliars and pull the clip and check the piston, seals and bore.  Maybe it will be serviceable.

[Vinhead1957]

You have your work cut out for you. May consider a new tank

[lucky]

Thank you guys ... for the ideas.

CalJ ... i never heard of evaporust or "the works".  When I get notice of a product like this no matter what, I always look at the national safety data sheet.  It lists the mixture - carb cleaner for example is just acetone.  Thanks I'll check them out.

Flybox ... that's exactly what I've been doing ... on my running bike, i could disassemble the carbs every spring ... and clean them with carb cleaner and blow them out and it was good to go.  This one was sitting with gas in it for 25 years and its like a cement.  I hammered the wire end a little to form an edge on it like a screwdriver and twisted it town to cut through ... and there is tan powder.  But, it ain't happening.  I can go down fairly far with the wire (photo1) but not to the bottom; and i can get in all the way from the tube on the intake side.  it seems like its clogged right in that area where it jogs.  I'm reluctant to pull that pin out.

harisuluv:  ... thanks.  that pin is a slow jet?  I thought it was just a tube going down to the low part of the fuel bowl so it could suck gas from the bottom.  Like I said above, I'm reluctant to pull that out because ... because nothing seems to go right the first time you do anything.  :-) 

I thought the two nozzels were independent.  I marked that photo #2 wrong.  The nozzel that is NOT centered (off to the side a bit) seems to run all the way back to the "jog" and then up the tube.  BUT, if i blow air into that nozzel, it blows out like you said to somewhere.  I didnt take those little short fuel lines that run between the carbs off.  But, It seems like it came out that hose.  The center nozzel ran somewhere and I guess that one goes to the accelerator pump.  That seems to be clear.

Thanks for the information guys. 

http://forums.sohc4.net/index.php?topic=106060.0
I searched and found this link ... thanks again for the "breadcrumbs".

Tim

The stock idle jet is only .013 thousandths. A paper clip will not work. It will damage the jet.
You can use a #10(.010) electric guitar string and those can be purchased separately at a music store. Then use carb spray and compressed air. Make sure that you can hold them up to the daylight and wee the hole is open.

[TimK]

Thanks Lucky for the number.  I was looking for that and couldn't find it anywhere.  Yeah, I posted a photo of cleaned jet (above on page 1).

I pulled the filter using a 3/8-16 tap.  I only had to grip it with a pair of needle nose pliers so it didn't take a lot to get it out.  Just rocked it a liitle and it came right out.