Topic: For those that have increased main jet size...

[fmctm1sw]

Situation:  I reamed my emulsion tubes to try to address just-off-idle blubbering issues I had.  There were three passages in the top of each tube and reamed all three passages (thread posted here somewhere).  While the jury is still out on the effects, I lost 1/2 to full throttle.  I bought new plugs and did a chop the best I could keeping it right on the edge of bogging out.  I marked my throttle and all is good until 1/2.  1/2 to 3/4 is dicey and 3/4 and up totally non existent.  The plugs (except for a small difference in #1), were completely clean.  If an overly rich condition existed, I would have expected carbon build up.  I'm guessing it's too lean due to the added availability of air via the emulsion tubes.  My question is, how far up have you all gone when you rejetted?  Is 10% a reasonable guess?  The jets are about $5/ea or I could buy (cheaper) two more jet reamers in sizes of about .081 and .084.  I have 75s or 78s in it right now.  I'm right at sea level in miserable humidity most of the time.

[lucky]

Situation:  I reamed my emulsion tubes to try to address just-off-idle blubbering issues I had.  There were three passages in the top of each tube and reamed all three passages (thread posted here somewhere).  While the jury is still out on the effects, I lost 1/2 to full throttle.  I bought new plugs and did a chop the best I could keeping it right on the edge of bogging out.  I marked my throttle and all is good until 1/2.  1/2 to 3/4 is dicey and 3/4 and up totally non existent.  The plugs (except for a small difference in #1), were completely clean.  If an overly rich condition existed, I would have expected carbon build up.  I'm guessing it's too lean due to the added availability of air via the emulsion tubes.  My question is, how far up have you all gone when you rejetted?  Is 10% a reasonable guess?  The jets are about $5/ea or I could buy (cheaper) two more jet reamers in sizes of about .081 and .084.  I have 75s or 78s in it right now.  I'm right at sea level in miserable humidity most of the time.

In 50 years of working on motorcycle carbs I do not know of anyone drilling out emulsion tubes. ...Untill now.

[fmctm1sw]

Situation:  I reamed my emulsion tubes to try to address just-off-idle blubbering issues I had.  There were three passages in the top of each tube and reamed all three passages (thread posted here somewhere).  While the jury is still out on the effects, I lost 1/2 to full throttle.  I bought new plugs and did a chop the best I could keeping it right on the edge of bogging out.  I marked my throttle and all is good until 1/2.  1/2 to 3/4 is dicey and 3/4 and up totally non existent.  The plugs (except for a small difference in #1), were completely clean.  If an overly rich condition existed, I would have expected carbon build up.  I'm guessing it's too lean due to the added availability of air via the emulsion tubes.  My question is, how far up have you all gone when you rejetted?  Is 10% a reasonable guess?  The jets are about $5/ea or I could buy (cheaper) two more jet reamers in sizes of about .081 and .084.  I have 75s or 78s in it right now.  I'm right at sea level in miserable humidity most of the time.

In 50 years of working on motorcycle carbs I do not know of anyone drilling out emulsion tubes. ...Untill now.

Well, in your 50 years of experience, how much larger have you gone up in main jet size?

[Bootlegger56]

Are you talking about the mod in FAQ "thoughts of Hondaman" to increase the upper holes in the emulsion (jet holder) tubes to @ .039?  If so....I would be curious in the end result as I am contemplating the same mod to my K5 to resolve the same issue.....the off-idle blubber or slight stumble.  Sounds to me that if I do perform this mod I should stick to a slight increase.  How big and how many of the holes did you enlarge?  I appreciate the feedback.  I have tried just about every trick on here to address this annoying but livable issue.

[fmctm1sw]

Are you talking about the mod in FAQ "thoughts of Hondaman" to increase the upper holes in the emulsion (jet holder) tubes to @ .039?  If so....I would be curious in the end result as I am contemplating the same mod to my K5 to resolve the same issue.....the off-idle blubber or slight stumble.  Sounds to me that if I do perform this mod I should stick to a slight increase.  How big and how many of the holes did you enlarge?  I appreciate the feedback.  I have tried just about every trick on here to address this annoying but livable issue.

Yes, as described here in the FAQ:  http://forums.sohc4.net/index.php?topic=7401.msg103734#msg103734  Here's a link to my post:  http://forums.sohc4.net/index.php?topic=103547.0  I had three passages in the top of the tube.  In my post, you can only see two but there is another one perpendicular to these two.  I did all three at .040.  I bought a single reamer for about $15 figuring that was the only size I'd ever need.  My issue was most noticable on acceleration from deceleration if that makes sense.  Imagine riding at speed and closing the throttle (engine braking) and opening up the throttle back up.  A little stumble results.  Not life and death as you said but noticable, and my other 350F doesn't do it.  I may have created too much air flow but I'd be fine with that if correcting that issue necessitates larger mains.  There's got to be a limit to what the 350F can handle jet-wise.  I mean, nobody is running 110s in their 350F are they?  BTW, I did calculate the jet size if reamed with my .040 reamer.  It would make it about 102.  I'm thinking too big.