Intake and shims and its a bear!

Still can't find a shim to fit my new carburetor. Intake is 12.7mm id and the carburetor shim needs to be 21mm od. Its a 14 12 dellorto sha clone. Not a knock off. I really don't know about upgrading as my mechanical abilities are in uterum. Could I trade out the intake for a larger one and still use this carburetor without having to modify anything else? I tried to make my own shim but to no avail. Is there a place that can make shims to order? Thanks for you time

Re: Intake and shims and its a bear!

Brandon Weiss (Detective brandon to you) /

Measure the OD of the intake, then measure the ID of the carb clamp, not the inlet. Lets say the intake is 21mm OD, and your carb clamp is 18mm ID...that's a 3mm difference, half that is 1.5mm, so your need a 1.5mm shim. Whatever your difference is, divide it in half and that's your shim size.

You dont need a perfectly round shim that fits perfecto, in a pinch you could cut a small strip of plastic from an HDPE milk carton and and fine tune for a snug fit on the intake, and just use an O ring for the actual sealing.

Re: Intake and shims and its a bear!

Hey and thanks. My intake is 12. The inner of the carburetor is 20mm. That's an 8mm difference. Does that mean i need a 4mm shim? I don't think they make them that size. At least I can't find one. Maybe " two" 2mm shims? Thanks again

Re: Intake and shims and its a bear!

No. Logically, two wont do. I feel so dumb sometimes. he, he , he!

Re: Intake and shims and its a bear!

You say you have 12mm intake . That's likely the inside diameter .

What is the outside diameter of the intake ?

Re: Intake and shims and its a bear!

12.7 to be exact.

Re: Intake and shims and its a bear!

Dirty30 Dillon /

You're measuring the ID of the intake, you need to measure the OD. the OD cannot be 12.7mm

Re: Intake and shims and its a bear!

It has a 1/2 inch od. That =12.7mm The intake has 12 stamped on it. Am i dumb? He, he, he. I feel it. Thanks for your help

Re: Intake and shims and its a bear!

> roy cordero Wrote:

> -------------------------------------------------------

> It has a 1/2 inch od. That =12.7mm The intake has 12 stamped on it. Am

> i dumb? He, he, he. I feel it. Thanks for your help

Post a pic of that intake with a ruler at it opening .

Re: Intake and shims and its a bear!

Thanks, I will tomorrow.

Re: Intake and shims and its a bear!

Heres a pick of the intake. Hard to take pic and ruler at same time but there you have it. At the most it's 13mm. thanks for your help. Ironically, i still don't know if this is the reason my bike wont start. Just haven't got past the carb test.

carb1.jpg

Re: Intake and shims and its a bear!

Dirty30 Dillon /

Yes, you are measuring incorrectly.

You need to measure from the outside (the O in OD) face of the intake. I have marked it in red in the photo.

Capture.JPG

Re: Intake and shims and its a bear!

Even with that its going to only be like 14mm. Maybe 15. Need a 21mm od and a 15mm (if its that). I still can't find one that size. I ordered _for the hell of it_

a 21od by 16.3 id. Smallest inner diameter one I could find.

Re: Intake and shims and its a bear!

By your photo, you have an OD (Outside diameter) of around 17-18 mm. It's not reasonably possible to have an ID (inside diameter) of 13mm and an OD of 14mm; the walls would be too thin.

You really need to spend a couple bucks on a micrometer, and measure ACCURATELY the OD of your intake, as well as the ID of your carburetor body.

Re: Intake and shims and its a bear!

Ok. I do need to get one. But i do think it's smaller than 18 because the carburetor I bought came with a shim that size and its too big. It didn't seem possible to me either. Thanks for all your help.

Re: Intake and shims and its a bear!

Haven't bought a micrometer yet but I did receive the shim I ordered 21 mm od and 16.3 id. Its still too big for my intake . Almost worked but... Also it sticks out a bit from the carb- is that so you can use the o ring? I'm afraid the hammer it in further without harming the carburetor.

Re: Intake and shims and its a bear!

Today I learnt how to measure.

Re: Intake and shims and its a bear!

The smallest shim i could find was 21od (which I need) 16.3 mm id. I just bought it because it was the closest. I understand that I need a micrometer to measure it correctly but alas if they don't make it small enough... I saw one that's 18mm od and 16mm id. That's the smallest Inner diameter I found. But 18mm od is too small.Tried to find a bigger intake -if possible to do-but nothing that looked like the one i have. I did see one but "out of stock". Thanks again

Re: Intake and shims and its a bear!

Ok, I finally figured out that what everybody is calling a shim I would call a sleeve. Go down to the hardware store with your ruler. You would be surprised the different sized pipes (plumbing), tubes (conduit) and rubber hose (big and thick) you can find there.

Wait a minute...I just went out to my garage and measured a piece of scrap automotive heater hose.

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Re: Intake and shims and its a bear!

Thanks for the good idea. Just need the tool.

Re: Intake and shims and its a bear!

You need the 2 1/2 shim 16 inch inner diameter to 21 outer diameter. Treats and did cycles has em

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