Petcock Question - Suzuki Tank on a Honda

[Steve]

The carbs are Keihin for the Honda of course and it was missing one jet along with bowl screws (remember this was a free bike). The missing jet was a 118 size and I didn't have any Mikuni 118 jets on hand so I ordered one from Jets R Us online.

OK, I made a mistake, but it still works in principle.
Somehow, I was hung up on the 550T reference, forgot that the engine in the bike was a Honda.
And there was mention of a Mikuni 118 jet.

Just curious... What made you assume he wasn't? Sounds like a good project to fill in a little time. Good luck!

That part is quite simple. Mikuni does not use "118" in their main jet numbering.

Few that routinely offer assistance here on the GSR site are more knowledgeable and quick to offer good guidance/input than Steve. So I suspect there is a reason for this question that he'll share with us in his reply.

As listed above, but just like the TV commercial, "but wait, THERE'S MORE!!"

I don't know about the thread size difference between the Kehin and Mikuni jets, but the hole size of a Kehin 118 is the same as a Mikuni 105. The closest Mikuni jet to a 118 would be a 117.5, and its Kehin equivalent is 135, so you would have been running REALLY rich on that cylinder.

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[Mr.humbucker]

OK, I made a mistake, but it still works in principle.
Somehow, I was hung up on the 550T reference, forgot that the engine in the bike was a Honda.
And there was mention of a Mikuni 118 jet.



That part is quite simple. Mikuni does not use "118" in their main jet numbering.




As listed above, but just like the TV commercial, "but wait, THERE'S MORE!!"

I don't know about the thread size difference between the Kehin and Mikuni jets, but the hole size of a Kehin 118 is the same as a Mikuni 105. The closest Mikuni jet to a 118 would be a 117.5, and its Kehin equivalent is 135, so you would have been running REALLY rich on that cylinder.

.

See ... I told you there was a reason! After reading the last paragraph twice, ok three times, I follow yer think'n, I think. I will let you know on the thread size, my suspicion is that they're the same.

You do raise a question for me here, if the two carb manufacturers use different sizing systems, is there a system/correlation to metric measurements for either? Hope that made sense.

[Steve]

You do raise a question for me here, if the two carb manufacturers use different sizing systems, is there a system/correlation to metric measurements for either? Hope that made sense.

I have read a paper on jet sizing, but don't remember some of the details. One manufacturer (I don't remember which one ) numbers the jets based on the actual diameter of the hole. Another one numbers the jets based on the quantity of fuel that can flow through the hole in a given amount of time. And there are other methods of numbering, too. I have a chart that compares Keihin, Mikuni and DynoJet, they are all different.

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[Mr.humbucker]

I have read a paper on jet sizing, but don't remember some of the details. One manufacturer (I don't remember which one ) numbers the jets based on the actual diameter of the hole. Another one numbers the jets based on the quantity of fuel that can flow through the hole in a given amount of time. And there are other methods of numbering, too. I have a chart that compares Keihin, Mikuni and DynoJet, they are all different.

.

My first thought would be to size them by diameter if I were the manufacturer (no worries of that ever happening) but when I think about it it is all about the flow rate yet that could very on temperature and viscosity maybe? Good to know they're sized differently by manufacturer .... my day is complete now that I have learned something new about these bikes ... hey maybe that's a new category we can add ... GS Learning: Fact of the Day. 365 later we will all know a lot more.