Please help ID these carbs

[eric2281]

I bought these last week off ebay. Guy said they came off an '86 gsxr 750. I'm sure these are not '86 carbs b/c the inlets are oval, not round. They are slingshot carbs (or so I think). I'm not familiar with mikuni carbs at all & just trying to learn what I have.

In this last pic, the tube (high speed circuit?) is cracked at the bottom base. Does anyone sell replacements? ...or maybe a trick to fixing it?


My plan is to clean them up and retrofit them on my '80 cb750.

Thanks,

Eric

 

[eric2281]

BTW,

If you think they're dirty now...You should of seen them when I got them. The float bowls and pretty much all of the internals looked like they were covered in maple syrup. LOL.

 

[teazer]

They do look like Slinghshot carbs 34 or 36mm?

They are a bit of a mess though.

 

[djelliott]

Look very similar to a set I just rebuilt off of a Kawasaki ZX-7 H1.

 

[eric2281]

They do look like Slinghshot carbs 34 or 36mm?

They are a bit of a mess though.

They're 34mm. They were messier when they got here. The main jets, needles, and pilot jets are still soaking in pine sol as we speak. lol. Mains are 125. Pilots are 32.5. The needle has rings at the top w/an e-clip on the 3rd ring. Is that a dynojet feature?

 

[teazer]

What needles are in there? They should be marked and they changed a lot over the years but main jets were usually around 112.5 so maybe they were jetted for something.

 

[eric2281]

What needles are in there? They should be marked and they changed a lot over the years but main jets were usually around 112.5 so maybe they were jetted for something.

This is not my pic but my needles look like the one on the left.

 

[teazer]

I need to know what numbers/letters are stamped into the needle. It will be something like 5DP2 or 4FL or whatever.

They may also be from a GSX if they are only 34mm or perhaps a different make of bike.

 

[eric2281]

I need to know what numbers/letters are stamped into the needle. It will be something like 5DP2 or 4FL or whatever.

They may also be from a GSX if they are only 34mm or perhaps a different make of bike.

I double-checked the needles & I don't see any markings on them.

 

[teazer]

They must be aftermarket then. All Mikuni needles are stamped with a letter/number. Those would normally be 5DL11 or 5DL16 for later BST34ss and 4CO9-1 for 87 model 750 GSXR carbs. Most of the others are 36mm.

If there is no number it's going to be hard to work out what it needs and I'd hate to see you spend a fortune on brass getting them to work.

 

[eric2281]

I think I made a measurement mistake. The inlet side (facing air filter) is 34mm. The outlet side (facing engine) is 36mm. Are they indeed 36mm? If so, am I barking up the wrong tree trying to install these on a stock 750?

 

[teazer]

Nah. She'll be right.

A bigger risk is that because we don't know what they are off, they may require extensive changes in brass. I'd go ahead and try them and while they are soaking, ask around and find out what jets, and needles everyone else used so that you have a basis for comparison.

 

[eric2281]

Nah. She'll be right.

A bigger risk is that because we don't know what they are off, they may require extensive changes in brass. I'd go ahead and try them and while they are soaking, ask around and find out what jets, and needles everyone else used so that you have a basis for comparison.

Will do. Thanks for the help! I'll try to install them sometime during the week.