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Tue Jul 31, 2018 7:29 am

Is there a weber jet hole conversion chart for drill bits??I don't want to order a bunch of jets if I don't have to guys.would like to drill the ones out I have to get a ballpark for what size to buy.i know a lot of guys don't like to drill them but some do.it would make it easier for me then ill know what jets to actually buy.thanx Sean...

Tue Jul 31, 2018 10:27 am

I'm pretty sure the jet sizes correspond to the side of the bore in metric measurements. For instance a 135 jet would have a 1.35mm bore, and a 200 jet would be a 2mm bore, etc, etc, etc. lots of metric conversion charts out there.

brad

Tue Jul 31, 2018 12:27 pm

According to one of the official Weber resellers, the bores don't correspond to anything and, in some cases, don't necessarily go "in order". If you're set on drilling the jets, just go to a hobby store and get a pin drill set. Find the bit that matches as close as possible to the existing jet hole, and step up from there. I've got a box full of jets that fit the DCNF (and maybe some for a DCOE), so if you're running one of those I might have one that you can use.

Tue Jul 31, 2018 12:34 pm

I sure seems that you could measure your "Jet Plug Gauge" with the same measuring instrument (micrometer) that you measure your drill bits with . . . NO chart needed! :wink:
https://www.amazon.com/Carburator-Guage-Weber-Sole...N0EF1RBVJY

Tue Jul 31, 2018 1:17 pm

Letterman7 wrote: According to one of the official Weber resellers, the bores don't correspond to anything and, in some cases, don't necessarily go "in order".

That is true with the emulsion tubes but not with jets. The jets are just the metric size diameter as Brad pointed out.

Tue Jul 31, 2018 4:52 pm

Ya emulsion tubes are some weird voodoo made up numbering system. Lots of fun to figure those out. LOL

brad

Tue Jul 31, 2018 6:23 pm

vwracerdave wrote: Letterman7 wrote: According to one of the official Weber resellers, the bores don't correspond to anything and, in some cases, don't necessarily go "in order".

That is true with the emulsion tubes but not with jets. The jets are just the metric size diameter as Brad pointed out.

:oops: My bad. Yeah, got the two confused, sorry about that!

Tue Jul 31, 2018 7:54 pm

Main jets and idles jets are in MM so for instance a 120 main would be 1.20mm, ect..... Some people resort to number drills instead of metrics.... Number drills and good micrometer (in metric) and calipers can be of use (or decimal inches to metric conversion table/software/app) ...

This book lays out all the specs of emulsion tubes, air correction jets, main jets, idle jets.....

https://socalautoparts.com/shop/books-manuals/manuals/weber-tuning-manual/

But I would shop for best pricing....

Jet drills/reamers, jet gauges and other tools...

http://piercemanifolds.com

Dale

Wed Aug 01, 2018 4:08 am

once again thanks for the info guys.i thought my jets were to small(popping) but not sure now.i pulled all the new bosch plugs yesterday they r all seriously carbond up.really dry sooty carbon.I checked for air leak,compression test,timing etc everything good..I checked spark one plug at a time and I have a really yellow to white spark.and u don't get much of a difference pulling 1 and 2 plug wires off while running.and mixture screws don't affect anything much either.i have a old original blue coil from the 70,s I am going to replace today.everything else is brand new.it ohms out(my coil) at 3.7 and 7500 but somethings wrong.my jets r 50 and 115 so I doubt its to rich.i cleaned plugs and took it for an 10 mile ride no popping at all.and I ran high test.but my spark looks like shit.ill try the new coil today.its eating boat loads of gas also.

Wed Aug 01, 2018 5:24 am

It could be just basic carb adjustment that is problem....

Since webers usually run pretty much on idle circuits till transition (somewhere around mid rpm range -3000 rpm?) I would go back and do "lean best idle procedure" again and see if you can lean the pig out a bit...

Dale

Wed Aug 01, 2018 5:54 am

will try that also thanks dale..

Wed Aug 01, 2018 9:33 pm

Stop right where you are and figure out your ignition problem. A yellow or white spark is a weak spark. You should have a nice blue spark. This is why your plugs are shooting up, poor combustion, not running rich, or at least not confirmed yet. Fix your ignition.

brad

Thu Aug 02, 2018 5:15 am

slalombuggy,yes I went and picked up a new 12 volt 3 ohm coil last night.i wont change ANYTHING until I get a nice blue spark..my dizzy is brand new but I have an ancient bosch blue coil.i will test the new coil today.

Fri Aug 03, 2018 5:23 pm

I put new coil in.it runs decent has a yellow bluish spark.but it just seems like its misfiring.its Not popping.but plugs r soot black again.this is the STRANGE PART.if I pull number 1 spark plug wire while its running(out of dizzy cap) and I hold the wire 1/2 inch from the caps hole the idle clears up and it runs great!!.if I plug the wire in to the hole it studders a bit and is just misfiring a bit on number 1.i can watch the spark jump 1/2 from wire into the hole and the engine clears up!!!..so weird????..…..my compression is 120 plus all the way around.i dble checked tonight.my voltage at coil is 12.3 exactly what it is at the battery.and I dble checked my ground strap.i sprayed whole engine with ether,no air leaks.its got to be a crappy EMPI distributer?????,I also switched from points to electric...both the same.if I unplug number 1 wire and lay it on cap the spark jumps to the hole and it runs great...…..confused??????….its blue out of coil and yellow,blue,whiteish out of plugs.(I am not impressed with the spark out of the plugs).any ideas guys.i checked the cap for cracks.its ALL brand new...

Sat Aug 04, 2018 4:01 am

Try swapping the 1 and 2 plug wires and see if the problem moves. When you pull the wire out of the cap you are forcing the coil to put out a higher voltage to jump the gap which causes a hotter spark at the plug.

brad

Sat Aug 04, 2018 4:35 am

Brad I swapped them it stayed at number 1.u are right I read an arcticle, a guy had the same problem.i think my plug(s) is no good.and the spark finally happens(builds up) when I hold the wire away.i have not changed the plugs.i cleaned the carbon off of them and re ran them.any recommendations on a good plug?. NGK? maybe.i didn't even think that my new bosch plugs were No good.

Sun Aug 05, 2018 7:45 pm

all this grief over one BAD BOSCH SPARKPLUG...I moved number 1 sparkplug to number 4 cylinder.and number 4 wouldn't run right.unbelievable, it was a brand new plug.looks fine and its clean.just wont fire consistently...I changed my plug PROBLEM SOLVED!!!...it runs great guys.very happy with it now.THANKS for all the help...these new bosch plugs from ebay r CRAP!!!...I cleaned up an old original bosch plug from the 1970,s that says GERMANY on it,and it fires better than my other 3 brand new bosch plugs...ill be looking for NOS bosch plugs..

Mon Aug 06, 2018 6:39 am

Welcome to the new world where nothing fits, nothing is quality, nothing has good reputation, everybody is wrong (by another person's concepts), everybody is angry and it's not going to get any better.....

Dale