Author Topic: Bike boggy at low and high end  (Read 1091 times)

0 Members and 1 Guest are viewing this topic.

Offline B.A.S.

  • Jr. Member
  • **
  • Posts: 30
  • Karma: 0
    • Minnesota
Bike boggy at low and high end
« on: April 13, 2016, 02:15:46 AM »
Hi Guys,

I am at my wits end with this problem on my 1974 TX500.

- Bike is completely stock with intact airbox, carbs jets, etc.
- Top end has been completely redone. New rings, bore, rubber, gaskets, valves, timing, clearances, points, etc.
- Carbs completely restored to factory settings, correct jet sizing, etc.

Symptoms:

Bike runs and idles great. Holds around 1200-1500 rpm resting. Compression ~140 psi on both sides. Battery holds charge with ~13V running, stator working (magnet test), fuses intact, working signals, lights, electrical, etc.

- Bike bogs down when accelerating from zero, requires feathering of clutch to keep rpms high enough to accelerate
- Gears 2-3 acceleration is slightly choppy
- Gear 4 and any speed above ~65 mph bike bogs again

I feel like I am chasing my tail. I've gone up and down with the bike to find the root cause. Any suggestions would help! I am happy to provide any additional info needed.



Offline guylr

  • Administrator
  • Hero Member
  • *****
  • Posts: 1218
  • Karma: 19
    • ATL in the USA
Re: Bike boggy at low and high end
« Reply #1 on: April 13, 2016, 04:11:01 AM »
Does it start without the choke? We're the carbs cleaned recently? If yes and yes then you may be missing the main fuel rubber blind plug. See the parts catalog carb page and look for reference number 19.

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"

Offline B.A.S.

  • Jr. Member
  • **
  • Posts: 30
  • Karma: 0
    • Minnesota
Re: Bike boggy at low and high end
« Reply #2 on: April 14, 2016, 12:34:44 AM »
9/10 times it won't start cold without choke. Carbs were fully cleaned and factor size jets put in. I have the rubber plugs, I actually made good replacements from a thread posted here awhile back and then eventually found OEM replacements from NW vintage.

Latest info: plug chops are a bit black and sooty. I have a weaker spark, however boots and wiring checks out normal with ohmmeter.