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Confirm OEM needle shim thickness

Old 09-22-2012, 08:33 AM
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Confirm OEM needle shim thickness

Getting ready to work on carbs as soon as the man in brown gets to the driveway.

Need to confirm the OEM shim thickness of the one found under the needle on a stock carb / needle.

I found what i have front to rear are not the same.... so i want to get the base line set right with a couple of lapped shims of the same thickness.

Then I'll add 1 each .040 lapped shim to each OEM needle and see where Im at.

This is all part of getting rid of the DJ kit in place now.


Thanks
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Old 09-22-2012, 09:43 AM
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Originally Posted by VTRsurfer View Post
I don't have one out to check, but they're about .010" max.
Thanks...

Really looking for someone with a spare and a mic, as I want to get two of the correct size in there, as this is a thrice owned bike, I do not know if what is there is OEM.

And you can not order them on their own or i would....I have the OEM needles, no need for a new set,just to get the shims.

Erik
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Old 09-23-2012, 10:56 AM
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I believe they are 0.020" (don't have my jet kit here to verify but I measured them as well as a whole of small washers I bought in order to be able to conduct some fine-tuning on the jetting). Word of advice: buy yourself a digital caliper, they're quite cheap and take the guesswork out of it....
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Old 09-23-2012, 11:46 AM
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Originally Posted by mikstr View Post
Word of advice: buy yourself a digital caliper, they're quite cheap and take the guesswork out of it....
Thanks, Tools to measure are not an issue (BTW calipers are just a "rough guess" when it comes to Machine work, Micrometers are what we use when we want to know with some level of precision)
The issue is having a known base, ie a genuine OEM shim to measure.

I may have OEM shims on mine, or not, but they differ in thickness by a few .001 so I was looking for someone with a known OEM shim to measure.

Seems no one is going to be able to assist, so I'll just have to settle with using an educated guess on the thickness of an OEM shim, and make two of the same.

At least it'll be a known and even setting to start with.
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Old 09-23-2012, 12:50 PM
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You guys really need to stop measuring in inches... It works on Harleys, and US made stuff, but I have yet to find anything on the VTR that isn't best measured and described using metric denominations...

The stock shims are 0.5 mm, exactly... Which measured with a sloppy caliper probably equates to roughly 0.02 inches... But it's actually 0.0196850394 inches if you want to be exact... And that's a number that makes no frickin sense at all, compared to the metric equivalent... Just saying...
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Old 09-23-2012, 03:16 PM
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I just measured some oem shims from a spare set of carbs, .010 just like VTRsurfer said.
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Old 09-24-2012, 10:10 AM
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Originally Posted by VTRsurfer View Post
I disagree, Tweety. The Euro model may have a different size shim, but the ones in my carbs are much thinner than 0.5mm (.020"). When I added a shim to each carb, about 3 years ago, the brass washers I bought were approximately .020". I determined the thickness by holding the washer along side a .020" feeler gauge (yeah I know, I need to buy a mic). The OEM shims on my California model VTR were about 1/2 the thickness of the .020" brass washers. That would make them .010" (.254mm). But then the CA model may be different from 49 states models and Euro models. They don't want us to burn as much gas here.

As for metric vs "standard". I had to teach the metric system to my automotive students, so they could read specs and measure parts, like brake rotor thickness, and adjust valves, etc. Every semester at least one student would adjust his valve lash to .025", when the spec was 0.25mm on the under hood decal or in the manual. Of course .025" is 2 1/2 times over the spec of 0.25mm (.010"). Fortunately, they were required to have me check their adjustment, so it would get corrected. Otherwise it would have sounded like they were driving a diesel.
Originally Posted by ascothawk View Post
I just measured some oem shims from a spare set of carbs, .010 just like VTRsurfer said.
I dunno if the differerence is from US to EU or if it's CA, or what it is, but mine are both dead on 0.5 mm... But then again, a lot of small things are different... I do however suspect that a good micrometer will say that they are then 0.25 mm exactly, not 2.54 which the inch equivalent would be... It may be I have the shimsize wrong for the US market, but I'm damned sure it's manufactured and measured to spec in metric...
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Old 09-24-2012, 05:07 PM
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Originally Posted by Tweety View Post
I dunno if the differerence is from US to EU or if it's CA, or what it is, but mine are both dead on 0.5 mm... But then again, a lot of small things are different... I do however suspect that a good micrometer will say that they are then 0.25 mm exactly, not 2.54 which the inch equivalent would be... It may be I have the shimsize wrong for the US market, but I'm damned sure it's manufactured and measured to spec in metric...
California has historically gotten screwed, performance wise, by emissions laws affecting 2 and 4 wheel vehicles. For decades, starting in the 1960's, Detroit made cars for California and cars for the other 49 states.

Gradually the 49 states emissions standards came up to the level of the California standards, so it's highly possible that all US emissions spec VTR's have a thinner shim (to lean out the a/f mixture and reduce CO and HC emissions) when compared to Euro spec models.

But of course, only we here in the Golden State got the addition of the lovely EVAP canister, hanging off the front of the bike behind the front wheel, like a giant black tumor. And none of us would ever think of removing that beautiful appendage.
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Old 09-24-2012, 05:12 PM
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The shim I measured just happened to be off a set of Ca. carbs.
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