xl350 single carb swap.

[nedmmo]

i want to start looking at replacing the god awful one and a half carb setup my 84 honda xl350 uses. its such a convuluted system that im sure a single carb would work. it is after all only a single cylinder dirtbike.

what size carb should i be looking for? any OE carbs i should search for?

 

[crazypj]

Slightly more complicated, it has a reed valve and works as a 'single valve' at idle
Two smaller carbs have a higher airspeed so are easier to get jetted right plus, have more total area than a single carb
It's possible to fit single carb but it needs an accelerator pump and you will lose some low end pick up
There used to be kits for the XR350 and 400 but they are not cheap

 

[nedmmo]

hmm so its possibly easier to jet this setup you say? thats kind of the reason i was thinking single carb. the bike at the moment is jetted 90% correct, on the side of too rich. the plug is black and sooty.

i bought a 6sigma jet kit, i feel like it was probably a waste seeing as all it included were 4 jets and some needle shims.

im going to read the carb tuning stickies and learn my ass some jetting knowledge

 

[crazypj]

Unfortunately I haven't had a 350 since the XR in 1980's so can't help much with jetting
I've found that re-setting floats 1mm higher than stock will clean things up though
The very early XR had a problem with ignition coils when hot, there wasn't enough airflow to keep them cool and they eventually broke down, something to check I guess?
Do resistance checks with coils heated to about 130 deg F

 

[nedmmo]

i will do that for peace of mind, but when i bought the bike its ran fine, no noticeable flat spots, possibly some backfiring on deccel. nothing wrong with the current jetting per se, but could just be cleaned up which im led to beleive is the most time consuming.