Metalwork...Honda cycle jet sizes?

I got the new used coil in the Honda XL350, after machining a new
mounting system, new condenser and cleaning up the wiring and now it
spluges out a really nice bright blue spark. So I cleaned out the gas
tank, put in a pint, double inline filters, pulled the bowl and spritzed
the carby with carb cleaner and tried to start it. It would run for a
few seconds, or at least bark and once I got it running for a few
minutes. This is when I discovered the clutch wasnt releasing...when I
kicked it into gear.
Getting the bike down off the table saw and pulling the table saw out of
the sheetrock ........
Anyways...I figured the carby needed to be cleaned out, so I took it
apart and cleaned all the various ports and passages, replaced the
various o rings...(Ive never seen a carby with that many seals, o rings
etc etc...daaayyyam...thankfuly Ive got a good supply of O
rings..thousands actually..I bought a pallet load)
I discovered that the "slow jet" was someones kludge..a 8-32 x1 bolt
some yoyo had drilled a .140 hole down the center (well..mostly down the
center...) and stuffed it up into the casting. I think it may have been
glued in place, but removing it took some effort and it wont stay in
place. Based on parts breakdown diagram...its supposed to be a totally
different shape, screwed into the casting...where there isnt any
threads..must have been stripped out. I can machine a new one..not an
issue, tap the carb casting, turn and thread a new jet from brass, no
biggy. But I dont know what the jet ID diameter is supposed to be. The
various parts lists say its supposed to be a #48 jet. No idea as to the
It of course is metric. While my HLV-h will thread metric..I cant tell
what the thread inside the jet well really is. I dont have any metric
thread gauges.
When I crank the bike over with the plug pushes out a very
visible cloud of fuel, and it wont start...wets the plug. So obviously
the homemade jet is way way over size and is probably leaking . There
isnt a Honda shop within 45 miles and the one I called couldnt tell me
what the ID was supposed to be. Float has been set to proper height as
has the needle and jet.
Ive got drills down to .003, so punching a new jet out isnt an issue
Anyone have any idea of how these are supposed to be sized? Is a #48
..48 mm? That would make it about .019" which sounds a bit small for
an idle or start jet, but might be ok....shrug. Im not a motorhead.
Ive got some .018 drills ( #77 drill) sp could knock one out easily....
I figure that the only reason it started at all was the jet was
partially plugged up....shrug.
Too small and it will idle lean and get hot and burn something up, too
big and it will continue to flood out.
Any ideas? Work has been rather slow, and over the holidays Ive got
time to work on the scooters along with other more important projects so
would like to get the Honda running. I take turns working on the 3
bikes, and its the Hondas turn.
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"They couldn't hit an elephant at this dist..."
Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of
Reply to
Gunner Asch
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A quick google suggests that Keihn sizes are metric (48 = 0.48mm), but Mikuni are not (flow-related?)
Memory suggests that just drilling a hole may not get the same result as a factory jet; small long holes and surface finish issues.
It might be cheaper & quicker to buy a used carb from ebay.
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Having a tiny bit of experience with bikes and carbs ... You're on track , the jet size is a .48 MM . I know that sounds small , but a lot of HD big twins run an idle jet that size . It's actually low speed , idle mix is controlled by a needle . What does the carb look like ? Does it have a vacuum controlled slide and a butterfly or a butterfly only ? Choke plate or enricher port ? Does it mount eith a flange or a rubber sleeve into a spigot ?
Reply to
Terry Coombs
Where to get jets (don't even try to make them, have to be reamed to tenths)
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Mounts to a rubber boot 15 degrees or so offset to the head. Called a side port engine. Rubber boot is stiff, but still good, no leaks.
That big visible cloud of gas that comes out the plug hole tells me its slurping up a shitload of fuel from somewheres, and the only thing not nominal (as far as I can tell, is the bastard idle jet)
"They couldn't hit an elephant at this dist..." Maj. Gen. John Sedgewick, killed by a sniper in 1864 at the battle of Spotsylvania
Reply to
Gunner Asch

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