Jetting

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Jetting

13 Aug 2026 21:01
#926708
Hi guy's. I'm a newbie, just picked up a 74 z1, purchased it at sea level, I live at 6500 ft,  the runs out at 5000 rpm. I need to rejet the mains and was wondering if I can remove them on the engine or do the carbs have to be removed. The carbs are vm it's and the jets are in the bottom. Any thoughts. Thanks
Rob
 

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Re: Jetting

14 Aug 2026 04:28
#926723
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Re: Jetting

15 Aug 2026 02:29
#926762
The 1974 Z1 was a split year, early and late. Early carbs used float bowls with a big 17mm main jet access nut on each bowl. Later version only had a small brass drain slotted screw per bowl. Which version do you have? 

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Re: Jetting

16 Aug 2026 07:05
#926804
Sorry for the lateness of the reply, totally my fault. Anyway I have vm38's.

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Re: Jetting

16 Aug 2026 07:09
#926805
Thanks for the heads up. All taken care of.
thanks
Rob

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Re: Jetting

16 Aug 2026 08:53
#926807
rwtylla wrote:
Sorry for the lateness of the reply, totally my fault. Anyway I have vm38's.
I'm sure you mean VM28's .
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/forum/23-for-sale/611992...lide-mikunis?start=1






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Re: Jetting

16 Aug 2026 13:01
#926810
There either a 38 or 39 there big mama's.  This engine is built. It's a 1087 cc with some nice size cams. . It hauls butt at sea level, but at 6500 ft it needs some different main jets.

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Re: Jetting

16 Aug 2026 14:00
#926812
rwtylla wrote:
There either a 38 or 39 there big mama's.  This engine is built. It's a 1087 cc with some nice size cams. . It hauls butt at sea level, but at 6500 ft it needs some different main jets.
I think you need to post some pics of the carbs you have to get the correct recommendations.
If they are a linked bank of four at 38mm they are not VM's but likely to be RS flatslides.


 
AIR CORRECTOR JETS FOR VM CARBS AND ETHANOL RESISTANT VITON CHOKE PLUNGER SEAL REPLACMENT FOR ALL CLASSIC AND MODERN MOTORCYCLE CARBURETTORS
www.kzrider.com/forum/23-for-sale/611992...lide-mikunis?start=1






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Re: Jetting

16 Aug 2026 14:33
#926813
YES, as Zed said, post some photos. Workin' in the dark here. But you said "nevermind" so does that mean you figured it out?

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Re: Jetting

18 Aug 2026 07:00
#926854
I'll get out the build sheet . I'm gonna pull the carbs this fall and get into em.thanks for your help, I know more now than I did before. Thanks

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