Author Topic: where do the jets hand off?  (Read 1095 times)

0 Members and 1 Guest are viewing this topic.

Offline phil71

  • Master
  • *****
  • Posts: 1,813
where do the jets hand off?
« on: June 20, 2011, 01:01:29 AM »
got a K1, which is running great, but under 4k rpm it seems to stutter a little. Actually, let me be more specific: If I'm actually accelerating, it's smooth as glass at any RPM, but at a 'cruise' (meaning a bit of equilibrium between power and coasting) it's kind of choppy under 4k rpm. If it's on the pilot jets under 4k, I'm thinking sync, and/or idle mixture screws.
  if it helps, i get some light exhaust popping and 'burbling' on decel in gear, but not if i yank the clutch in.
  In the past, I've had bikes with exhaust mods that acted like this, which would indicate a lean condition, but these HM300s are tight, and even, everything is bone stock.
Any ideas will be entertained. Thanks!

Offline Jon

  • Full Member
  • *
  • Posts: 51
Re: where do the jets hand off?
« Reply #1 on: June 20, 2011, 01:48:24 AM »
With engine off wind on full throttle & mark grip against switchblock, close throttle & mark again, split this into 1/4s.

This chart will then give you a pretty good idea what to adjust for a specific throttle opening.

« Last Edit: June 20, 2011, 01:51:04 AM by Jon »
Honda CB550f
Honda VFR400
Ducati 900 S2
Moto Guzzi LeMans III
BMW R90S

Offline flybox1

  • My wife thinks I'm a
  • Really Old Timer ...
  • *******
  • Posts: 14,301
Re: where do the jets hand off?
« Reply #2 on: June 20, 2011, 07:42:53 AM »
i would immediately attack my carbs, cleaning them, and after all other tuneup procedures were completed, id do a vacuum sync. this'll probably take care of the s-t-t-t-t-ttutter.
add a little seafoam to your next tanks of gas.
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mineā€¦"

Offline phil71

  • Master
  • *****
  • Posts: 1,813
Re: where do the jets hand off?
« Reply #3 on: June 20, 2011, 08:02:35 AM »
The carbs are as clean as they're ever going to be without a time machine . I think it's sync, which I did a few months ago, and just now realized I didn't lOck two of them down properly . What's funny is that, at the time I was unable to trust all my adjustments because the exhaust had holes. Now it's running like an animal, just with the slight stutter . I'll break out the ole gauges and go over it.

Offline Bodi

  • Really Old Timer ...
  • *******
  • Posts: 5,697
Re: where do the jets hand off?
« Reply #4 on: June 20, 2011, 10:06:03 AM »
Hmmm.
What's a "Straight Dia."??