- Posts: 534
- Thank you received: 20
Big vacuum difference 3 cyl around 20, one just 9.
- car5car
- Topic Author
- Offline
- Banned
Less
More
16 Aug 2013 13:41 #601704
by car5car
96 Yamaha Royal Star
82 Yamaha Virago 920
Big vacuum difference 3 cyl around 20, one just 9. was created by car5car
Good compression, I adjusted removed carbs, nothing changed. Checked manifolds, no leaks!
96 Yamaha Royal Star
82 Yamaha Virago 920
Please Log in or Create an account to join the conversation.
- 650ed
- Offline
- User
Less
More
- Posts: 15344
- Thank you received: 2829
16 Aug 2013 15:28 #601716
by 650ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Replied by 650ed on topic Big vacuum difference 3 cyl around 20, one just 9.
Does it improve when you adjust the carb sync screw to raise the slide? Also, have you checked the valve clearances? Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Please Log in or Create an account to join the conversation.
- car5car
- Topic Author
- Offline
- Banned
Less
More
- Posts: 534
- Thank you received: 20
16 Aug 2013 16:41 #601723
by car5car
96 Yamaha Royal Star
82 Yamaha Virago 920
Replied by car5car on topic Big vacuum difference 3 cyl around 20, one just 9.
I adjusted valves, all exhaust clearances were low, I switched shims and only needed 1 shim.
Compression is about 140 in problem cylinder.
I found air screw very tight, less than 1/4 out, adjusted it to 1 1/4 like book says, but it didn't change anything.
I removed pod filter from another cylinder, it didn't change vacuum in that cylinder (clogged filter check)
The only crazy idea is that carburator has hole in it sucking extra air (???????????)
Compression is about 140 in problem cylinder.
I found air screw very tight, less than 1/4 out, adjusted it to 1 1/4 like book says, but it didn't change anything.
I removed pod filter from another cylinder, it didn't change vacuum in that cylinder (clogged filter check)
The only crazy idea is that carburator has hole in it sucking extra air (???????????)
96 Yamaha Royal Star
82 Yamaha Virago 920
Please Log in or Create an account to join the conversation.
- 650ed
- Offline
- User
Less
More
- Posts: 15344
- Thank you received: 2829
16 Aug 2013 18:02 - 16 Aug 2013 18:04 #601740
by 650ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Replied by 650ed on topic Big vacuum difference 3 cyl around 20, one just 9.
Did you adjust the carb sync screw to raise or lower the slide to see if that changed the vacuum level? The sync screw is not the air screw. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Last edit: 16 Aug 2013 18:04 by 650ed.
Please Log in or Create an account to join the conversation.
- car5car
- Topic Author
- Offline
- Banned
Less
More
- Posts: 534
- Thank you received: 20
16 Aug 2013 20:17 #601753
by car5car
96 Yamaha Royal Star
82 Yamaha Virago 920
Replied by car5car on topic Big vacuum difference 3 cyl around 20, one just 9.
I was trying to adjust it, it didn't work.
My last chance was cleaning "choke" system. I pulled out all plungers, cleaned everything, it didn't work.
My last chance was cleaning "choke" system. I pulled out all plungers, cleaned everything, it didn't work.
96 Yamaha Royal Star
82 Yamaha Virago 920
Please Log in or Create an account to join the conversation.
- 650ed
- Offline
- User
Less
More
- Posts: 15344
- Thank you received: 2829
16 Aug 2013 20:43 #601759
by 650ed
Sorry, I don't understand "it didn't work." Was there a problem with the locknut and/or the screw, or were you able to loosen the locknut and turn the screw but there was no change in vacuum? We are talking about the same screw, right? The one under the carb's top cap? Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Replied by 650ed on topic Big vacuum difference 3 cyl around 20, one just 9.
car5car wrote: I was trying to adjust it, it didn't work.
.....
Sorry, I don't understand "it didn't work." Was there a problem with the locknut and/or the screw, or were you able to loosen the locknut and turn the screw but there was no change in vacuum? We are talking about the same screw, right? The one under the carb's top cap? Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Please Log in or Create an account to join the conversation.
- car5car
- Topic Author
- Offline
- Banned
Less
More
- Posts: 534
- Thank you received: 20
16 Aug 2013 21:11 - 16 Aug 2013 22:37 #601762
by car5car
I begun increasing vacuum in problem cylinder, it improved from 9 to 11, after that throttle valve touched bottom and begun rising 3 other valves, increasing idle.
Yes, screw under top cover.
96 Yamaha Royal Star
82 Yamaha Virago 920
Replied by car5car on topic Big vacuum difference 3 cyl around 20, one just 9.
650ed wrote:
car5car wrote: I was trying to adjust it, it didn't work.
.....
Sorry, I don't understand "it didn't work." Was there a problem with the locknut and/or the screw, or were you able to loosen the locknut and turn the screw but there was no change in vacuum? We are talking about the same screw, right? The one under the carb's top cap? Ed
I begun increasing vacuum in problem cylinder, it improved from 9 to 11, after that throttle valve touched bottom and begun rising 3 other valves, increasing idle.
Yes, screw under top cover.
96 Yamaha Royal Star
82 Yamaha Virago 920
Last edit: 16 Aug 2013 22:37 by car5car.
Please Log in or Create an account to join the conversation.
- car5car
- Topic Author
- Offline
- Banned
Less
More
- Posts: 534
- Thank you received: 20
17 Aug 2013 15:54 #601858
by car5car
96 Yamaha Royal Star
82 Yamaha Virago 920
Replied by car5car on topic Big vacuum difference 3 cyl around 20, one just 9.
Problem is solved!
I left vacuum port on 3rd carb open. (I thought, it was vent port, looks identical to vent ports on 2nd and 4th cyl.)
I left vacuum port on 3rd carb open. (I thought, it was vent port, looks identical to vent ports on 2nd and 4th cyl.)
96 Yamaha Royal Star
82 Yamaha Virago 920
Please Log in or Create an account to join the conversation.