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Well damned if this didn't just become the most useless thread ever.

Everybody needs to push away from the keyboard and go riding.
 

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most everything i ride leaks oil
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"according to them, the primary problem with bootleg jets for both keihin and mikuni was incorrect orifice per labeling of the jets." <- That's another way of saying they did not drill the hole the right size when they made it.
could have been drilling the wrong hole in a pre-stamped jet or stamping the wrong numbers on a pre-drilled jet. the result is the same but the sudco guy distinguished them for some reason.

even if the hole is the right size the shape of the orifice entrance will affect the flow. amal and mikuni jets are rated by cc per minute , and might flow differently from some other jet with the same diameter hole but a different shape. that's why pilot jets with buggered screw slots can flow differently from new ones.

EBC says their jets are flow-calibrated, so if they're telling the truth their jets should be fine.
 

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When you buy from the OEM manufacturer you are paying for the design and the quality control. Components are built to spec with tolerances indicated where required, entire manufacture process is going to be ISSO so they can manufacture or subcontract the product anywhere. Replacement parts markup is usually 300% minimum, over the price of what you paid for the entire carburetor.

When you buy from a reputable name supplier or manufacturer that for all we know might even be the original supplier :/ you are paying for the quality control and the manufactured product. Is EBC a reputable brand :/ pretty good in my experience (y)

and yes a jet is not a simple hole.
fwiw: Old timers used various sized sewing needles and spun those into the hole to enlarge it.
 

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When you buy from a reputable name supplier or manufacturer that for all we know might even be the original supplier :/ you are paying for the quality control and the manufactured product. Is EBC a reputable brand :/ pretty good in my experience (y)
sometimes there are odd connections with that. mikuni and amal were linked under the same corporation dating back to the 1930s, and so engineering developments would appear across company lines. the same man who designed the VM mikuni carburetor also did the amal mark2, which explains why they are so similar.

i was told once that they shared main jets as well, but a look at the amal website doesn't show anythjing that i've ever seen in a mikuni.
 

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hey dirk

i apologize if i came across as rude in my reply to you about jet quality. it wasnt my intention. its just that there is no answer to yiur question that has validity except by doibg it yourself. if you erace you know this.

i didnt mean to come across as an ass
 

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Discussion Starter · #31 ·
just put in a 810 kit with the gpz cams that dont have the tach drive on them. whats a good 4 cylinder tach? scitsu i like. maybe something cheaper.
 

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just put in a 810 kit with the gpz cams that dont have the tach drive on them. whats a good 4 cylinder tach? scitsu i like. maybe something cheaper.
I bought some boxes of parts the other day, some race parts and in them is an older aftermarket tach. I just took a quick glance, it's a nice looking unit, but was just opening boxes to see what was there. I'll take a better look at it tomorrow and see if it's junk or gold.
 

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just put in a 810 kit with the gpz cams that dont have the tach drive on them. whats a good 4 cylinder tach? scitsu i like. maybe something cheaper.
They didn't put their name on it
I bought some boxes of parts the other day, some race parts and in them is an older aftermarket tach. I just took a quick glance, it's a nice looking unit, but was just opening boxes to see what was there. I'll take a better look at it tomorrow and see if it's junk or gold.
No luck, it's cheap crap in a nice case.
 

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holy fucking hat. all i asked is if ebc jets where any fucking good. i had hoped someone who knows/ had used them could chime in with there 2 cents. a simple yes or no would be good, i dont need advice on how to tune/ build or race motorcycles. this is why we cant have nice things, carry on . thanks trials and rich for your help .
In my experience EBC jets are as good (or bad) as anything out there and better than most Chinese aftermarket jets or even genuine as they tend to have tighter tolerance, maybe 2% instead of common 10% production variation or 5% for 'precision' jets (mainly due to manufacturing process improvements)
Fake Kei-Hin pilot jets are easy to spot, they have 0.60mm cross drillings instead of 0.80mm cross drilling
Only problem is the numbers didn't match known sizes but that has probably been fixed? (Dynojet did the same but with arbitrary numbers :( and even nylon jets at one time)
Personally I prefer the Kei-Hin system of numbering.
It's much easier to check a hole size than a flow rate (cc/min, A MAL Miikuni, and a few 'race' Kei-Hin on Honda CR moto-crosser's,) particularly if you don't know what head was used (17", 19", or 21" plus metric, 450mm, 490mm 550mm)
I forget what system BING used, been a long time since I had my Maico 490 and even longer since I worked on BMW's.
Mikuni do make 'precision' jets, they are marked with 'squared off' 7 segment LED display type numbers instead of common rounded ones.
I don't remember if Kei-Hin did something similar ? (probably but can't remember)
Precision jets came out in mid 80's due to CARB but were great as they also came in odd numbers (manufacturer specific, 1cc from around 90 to 130)
It was possible to get jetting really close to 'perfect' throughout rpm range (and 4~5 thousand beyone redline)
 
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Sounds a little rich in vid?
 
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