Help me identify this carb?

[spazzed]

I've got a thread in the project forum but thought I might be able to get more specific help here.... Trying to figure out what jets/needles and rebuild gaskets I need to order for these carbs. Can't for the life of me figure out what mikuni they are (they don't match up to any of the mikuni measurements I can find online.) Only stamping is on the right side and says 193 E1. Came off a 180cc Yamaha YCS1 but don't seem to match the VM18 that is called out in the manual??

 

[duggyb]

arent you suppose to measure the inside of the bore? not the outer?

might be why your measurements are off.

 

[spazzed]

arent you suppose to measure the inside of the bore? not the outer?

might be why your measurements are off.

http://www.procycle.us/carb/mikuni_dimensions.htm makes it look like they are OD measurements? Except for the two called out as ID? Maybe I interpreted this wrong.....

 

[teazer]

Nominal size, as mentioned above, is the venturi bore. Not the OD where the filter goes or the spigot bore or the slide chamber OD.....

You will probably need old style inside calipers to measure the bore or telescope gauges. The slide should be 20 -22mm diameter in a VM18 carb.

 

[spazzed]

Nominal size, as mentioned above, is the venturi bore. Not the OD where the filter goes or the spigot bore or the slide chamber OD.....

You will probably need old style inside calipers to measure the bore or telescope gauges. The slide should be 20 -22mm diameter in a VM18 carb.

Which part is considered the "venturi?" Is this the ID of where the filter attaches?

I'll measure the slide. That's helpful, thanks!

 

[teazer]

Not quite. The venturi is the small central part under the slide. The intake has to be much larger than teh venturi in order to have a venturi effect.

SUDCO lists external dimensions so that people can determine whether or not they will physically fit in their applications.

 

[spazzed]

SUDCO lists external dimensions so that people can determine whether or not they will physically fit in their applications.

That makes sense. I'm not sure how I'll measure the venturi, but I'll try to figure it out. The slide is out so easy to measure.... I'll check it out when I get home tonight.

 

[spazzed]

The slide is 23mm. Does that tell you anything?

I haven't figured out how to get an accurate measurement of the venturi, yet.

 

[teazer]

Not too much but it's say 4-5mm larger than the venturi, so we know it's 18-20mm or in that ball park at least.

You could approximate it if you have some 3/4, 7/8 and 1.0" tube. Use them as a GO-NO GO gauge.

Grab one of these from your local hardware or tool store is a more accurate way

They are Inside calipers.

 

[crazypj]

You can get a basic measuring set from Harbor Freight for about $12.00
looks like its on sale
http://www.harborfreight.com/hand-tools/specialty-measuring/6-piece-technical-measuring-set-94447.html

 

[teazer]

Wow. PJ that's a great price

 

[crazypj]

Yep, I don't need any of it but I may pick one up just because it's so cheap and it's always handy to have 'spares'

 

[teazer]

The steel calipers and dividers I use came from my dad. They last forever.

 

[spazzed]

I picked up the last set of those at my local Harbor Freight. And.... if you've never had the pleasure of trying to locate the "last" one of something remaining in the inventory system at HF when there are not any items on the shelf.... I don't recommend it. A truly painful experience.

So -- when I get home tonight I should be able to measure the venturi and (hopefully) clear up whether these are VM18s or VM20s.

I did find out on another board from a guy that for sure has VM18s on his YCS1 that he thinks that I have the 5-port "high-performance" version of this engine that could very well have some larger carbs on it.