Author Topic: How dirty are your throttle bodies?  (Read 3269 times)

Offline Vespa no more

  • ^ Proficient Motobricker
  • Posts: 230
How dirty are your throttle bodies?
« on: April 19, 2017, 10:42:05 PM »
Pulled the throttles out and was impressed by the crud in them. 33 years old.


Nothing a toothbrush and fuel didn't fix.


Am expecting noticeable improvements along with the replacement of the inlet rubbers.


Guy
  • Wollongong NSW AUSTRALIA
  • K100RT 1984, K1100RT 1993, Vespa VNB125 1963 :)

Offline Motorhobo

  • +25 years of K75
  • ^ Quintessential Motobricker
  • Posts: 1530
Re: How dirty are your throttle bodies?
« Reply #1 on: April 20, 2017, 05:01:13 AM »
I completely disassembled mine to clean, i.e. broke the assembly down into the 3 component parts, and it took me many hours of trial and error to get them back together again -- once even got it installed on the bike only to find that it was still f93king wrong. So -- my advice...don't do that. Either take lots and lots of pictures or clean it as best as you can in one piece.
1994/1995 K75 ABS Frankenbike: original engine 136k miles, frame from Gary Weaver (RIP), 173k miles -- Current Odometer: 198k miles
1994 K75 since 2013, 82,000 mi (19k mine) w/California Sidecar Friendship II Sidecar & Black Lab 'Miss B' - RIP

Past: 1974 Honda 550/4 (first bike), 1994 K75 (sold), 1995 K75 ABS (parts bike), Sidecar Dog & Best Bud 'Bo' - RIP

Offline Vespa no more

  • ^ Proficient Motobricker
  • Posts: 230
Re: How dirty are your throttle bodies?
« Reply #2 on: April 20, 2017, 07:53:09 AM »
Yes I had read about the perils of pulling it apart.


I had previously done just that on some carbs from a R65 (just two Bing CV carbs) and had success. For me a significant trick was to leave the butterflies slightly loose and let the spring bring them back to fully closed before tightening the two screws holding the butterflies to the shaft.


But, while I wanted to do the same here, discretion prevailed.


The other thing (frowned on - so do it at your peril) was balancing the two carbs. With the bike idling, just pull one of the spark caps and count how many revolutions the bike can sustain before stalling. Then simply adjust the idle screws to match both sides up.


But I digress - the 4 throttle bodies on a K are quite different to the 2 carbs on a R series.


I can't got for the final balanced and smooth throttles yet, I have dismantled the bike and have just pulled the clutch today.


And a pleasant surprise - despite the bike being 33 years old and off the road for the past 8 years, the clutch plate was 5.20 (measured in three separate places). Given that the bike has 108, 000 kms on it, someone has had the clutch plate changed "recently".


Guy
  • Wollongong NSW AUSTRALIA
  • K100RT 1984, K1100RT 1993, Vespa VNB125 1963 :)

Offline alexis291

  • ^ Proficient Motobricker
  • Posts: 166
Re: How dirty are your throttle bodies?
« Reply #3 on: April 20, 2017, 05:33:24 PM »
Nice cleaning job! Lovely.


Sent from my iPhone using Tapatalk
  • UK
  • K1100RS 1995

Tags: