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Question. I need a source for good main jets for my xl600, preferably next size up from 155. I'm asking this because I live along way from any shop, and the internet is my parts dealer. Thanks!

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dual carbs as on XL600s only had 122 jets max. Have you changed to a single carb head/engine?

You should be able to get bigger than 122s..I had 125s or 128s in my 86 XL600..Surely wouldn't be putting 155s in a dual carb though..

must be a misprint wanting that size for a twin carb..

 

According to JetsRus you want the mains from the below..short screw type..I'd check your carb to make sure first as the 86 XL I used

to own ran a longer style jet with a hex head not a short screw head type..

 

http://www.jetsrus.com/a_jet_kit_dirt/honda_600_XL600R.html

Edited by Horri

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Wasn't implying you can't get larger than 122s only that 122s were the largest installed by the factory in dual carbs. 155s would be ridiculously rich in duals.

K..misread you there..

Edited by Horri

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I strongly suggest permanently marking the jets as being drilled to avoid confusing them with the original size.

 

The actual size is also not going to be accurate unless you use reamers.

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I'm going to agree with H/T..Drilling jets isn't accurate,,The drills aren't expensive but is the finished result dead accurate.

Can make working out tuning a bit difficult. I have a chart on drill sizes to carb main jet hole size if you want it..covers the Keihin jets.

Whether or not the chart is exactly right I don't know..Harvested it from somewhere around the net.

I tried doing as you are once,,Gave it a miss after trying to get exactly the right drill size.Even proper tool shops don't carry

a large range of drills in those tiny sizes..

 

I'm interested in what year XL you have and what shape the mains are,,Any info????

Edited by Horri

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Twist drills almost universally make a hole larger than the drill's diameter.

 

Keihin jet numbers refer to the orifice diameter in hundredths of a millimeter.

 

Jet number ÷ 100 = millimeters.

 

125 ÷ 100 = 1.25mm, etc.

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Ok, sorry for the misprint. I have a 118 in the left and a 115 in the right. I'm going to bore them out instead one size on each. Thoughts?

Sure. Experiment. Then go buy the CORRECT size. Throw the old jets away. Jet sizes raise in just a few thousanths per. Even the carb manufacturers have to custom order the reamers to make them. Drills don't come in close enough increments to work out generally. My highly modified 600 has 128s in both holes but it likely is richer than I needs to be.

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Hey thanks for the responses. I had a jet reamer handy, so I went up one size on both. And thank you horri for the link to jetsrus.com

So back to the bike. I have marked and reinstalled the mains and the bike runs fantastic. I have fine tuned the idol speed with the fuel screw and all is well. Bike no longer hesitates and has a lot more umf at high speeds. Installed a fuel filter and now it's time to ride!

Edit: horri, it's a 1987 xl600, piston bored .25 over with stock honda piston, supertrapp can ( soon to be 450x muffler ) and an unmodified airbox with stock air cleaner.

ImageUploadedByThumper Talk1397946872.636142.jpg

Edited by Fivefive1

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Yep,,Very good..I was mainly wanting to get a handle on what shape the main jets are in various year XL600

so I can do a file on them with the correct type of jets for different year XL so I get it right when sending people

on a jet mission to JetsRus or PJmotorsports..Confusion reigns a bit with the shapes so I want to get them right per the year bike.

My 86 XL had the long hex sort,,others seem to have the  short screw variety..confusing..Whether the actual length of them

protruding from the emulsion tube into the bowl makes any difference I don't know,,If I knew that it'd be simple..

 

Were they the short screw type,,or the longer hex head sort???

Edited by Horri

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