Calling all G-1 Folks - Carburetors

[mikeasis]

is there anything not removeable/swapable from the carb bodies? I ask because there is nothing really out there listed for the folks with 82 carts. I honestly don't now how different they are but they do carry different part numbers. I would assume just jetting differences as externally they look the same. Im going to dig one out in a bit and check the numbers on the jets.

[OgreTX]

In my opinion the entire carb can be stripped down to the cast body. I am not into manufacturing, but my view of these G1 carbs is that the entire body is cast metal (non-ferrous). The bodies are then drilled, tapped, etc. for the appropriate valve, jets, shafts, etc. Then the fuel bowl is added.

And now that I have given my opinion, check out the pic 1 below (G1 repair manual page 4-1) and notice the highlighted portion. So cgtech and smallblock, and others who have spent numerous hours fixing these carts would probably tell me to keep my opinion to myself. 'nuff said .

Ogre

Note added: BTW, that warning is from the Yamaha Repair manual. IMHO, you might not find that the Mokini replacements are so meticulously assembled. I would place money on it.

[griffo002]

HI OgreTX ...See if you get put as a sticky, as some helpful stuff in this thread.

Just a question on the pilot screw being different .Did you change or do a swap to see if the cart ran better of worse?

The thing is I lost my original one....I know...bloody old fool.:(
I have put the cheap one in and it runs but after all the new parts in but It may go better with original.
Thx....Griff

[OgreTX]

Hey Griff,

Thanks for bring my mind back to this one. The pilot screw from the junk carb has the same threads and the point maybe sharper than our original used ones. It should work ok.

I'd put it in by hand (no screwdriver) to determine that there are no rough snags from the cheap production, but if it goes in by hand it should work.

And back to the thanks, I need to finish this up with one more post to summarize my findings, and make a couple of recommendations.

HTH,
Ogre

[griffo002]

Hi Mate...When you get it up and running...just do a swap of the slow pilot jet,as you say they do fit.(I have the cheap jet in the Mikuni,original carb,it goes)
And see if there is any difference in the slow speed and take off of the cart please.
TH ol mate.Griff.
And to the Mods...Stick this thread as it has a all the goodies about G1 carbs.

[mikeasis]

Swapping carbs on my 80 j10 that is currently equipped with a j17 engine. I don't know how I missed it but the j17 carb is slightly different and actually is setup like the Mokuni carb with the overflow mounted on the other side.

[griffo002]

Are the jets the same do you know mike?

[mikeasis]

Originally Posted by griffo002

Are the jets the same do you know mike?

no jets are different. If anyone that has a j17 that needs carb work would either have to swap their old jets to the new carb or just use a mokuni as parts for say the shafts/ bushings float ect.

I had a J24 carb on my j17 engine and it ran good but fouled the plug often. cleaned up the j17 carb and jets and she runs great for a j17.

[mikeasis]

Heres what Ive found.

My J17 carb has main jet #95 and pilot jet 32.5 According to the parts site below these are correct.

I thought I had a J10 carb but ended up having 2 J24 carbs. Both have a main jet #97.5 however one has a 32.5 pilot and the other has a 42.5. The parts site below lists 95 and 32.5 with a 45 pilot being an option.

the site below lists the same jets OrgeTx found in his J10 carb, Main #100 and pilot #45. it looks like are the jet sizes are still available for all flavors

My mokuni has a 95 main and 38.8 pilot. Id guess you could contact Mikuni and give them a carb serial# and they could probably tell you what jets are available.

How much tuning you can do with the different jets is beyond me, Im not a carb guy. Its one thing when electrical gremlins get you on a fuel injection motor but it drives me nuts that something that operates on the same principles as a toilet bowl can kick my ***.

https://www.cmsnl.com/yamaha-g1_model16648/

[dezrcr822]

So it looks like the Mokini main jet is the same for the J17 at #95 and the pilot is a little richer at a #38.9(wonder if its 389). Can anyone tell to what throttle position pilot is in play for? Example throttle closed to 1/4 throttle. And also what throttle range the main jet is in play for? Carbs im used to tuning have more tunable parts like jet needles, throttle valves, needle jets ect... Thank you OgreTX and Mikeasis for putting this info together