BS34 correct Pilot Jet size determination

  • daveo
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BS34 correct Pilot Jet size determination

06 Oct 2015 05:30
#693558
How do I know which pilot jet size is correct for my carburetor, other than following what the FSM states? :S
1982 KZ1100-A2

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Re: BS34 correct Pilot Jet size determination

06 Oct 2015 13:41
#693602
Since you don't want to follow the FSM I guess you have changed something on the bike? It depends on what that is.
-[ KZ700-A1 '84 ]-

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Re: BS34 correct Pilot Jet size determination

06 Oct 2015 13:57
#693603
daveo wrote: How do I know which pilot jet size is correct for my carburetor, other than following what the FSM states? :S

Not sure if this really answers your question or not, but if the idle speed drops with the mixture screws about 1-2 turns out and drops again with them 3-4 turns out, then the pilot jet is the correct size. If it doesn't drop on the lean side, then your pilots are too large (or you have an enricher leak), and if it doesn't drop on the rich side, they're too small (or you have an air leak).
1997 KZ1000P (P16)
2001 KZ1000P (P20)
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Re: BS34 correct Pilot Jet size determination

06 Oct 2015 18:39 - 07 Oct 2015 03:26
#693621
TheForumTroll wrote: Since you don't want to follow the FSM I guess you have changed something on the bike? It depends on what that is.

The engine has an 84 ZN (GPZ) bathtub head and GPZ camshafts, with a V&H header, and Dyna 2000 ignition. Beneath the head the engine is stock.
The carbs had 132.5 mains and 40 pilots since the head was changed back in March, and it seemed to be running slightly lean. Yesterday I changed the pilots to 42.5 to see what effect it has.
1982 KZ1100-A2
Last edit: 07 Oct 2015 03:26 by daveo. Reason: weed out blab

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Re: BS34 correct Pilot Jet size determination

10 Oct 2015 04:52
#694033
jackleberry wrote:
daveo wrote: How do I know which pilot jet size is correct for my carburetor, other than following what the FSM states? :S

Not sure if this really answers your question or not, but if the idle speed drops with the mixture screws about 1-2 turns out and drops again with them 3-4 turns out, then the pilot jet is the correct size. If it doesn't drop on the lean side, then your pilots are too large (or you have an enricher leak), and if it doesn't drop on the rich side, they're too small (or you have an air leak).

Too blubberish with 42.5 pilot jets, so I'm back to crisp response with size 40. This time Genuine Mikuni...precision made with the hole exactly in the center:)
1982 KZ1100-A2

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