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Author Topic: Zenith carb  (Read 1676 times)

Gearhead-95

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Zenith carb
« on: January 11, 2021, 06:20:31 AM »
I’ve got what appears to be a 1956 or 1957 simplex. The bike looks mostly original. I’ve been cleaning it up and inspecting everything to get it running. When I pulled the carb to clean it and make new gaskets I saw it was a different carb than I’ve seen on other simplex’s. Did any bikes come original with a zenith carb? I’ll get part numbers off carb this evening. Thanks for any info
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Ricks

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Re: Zenith carb
« Reply #1 on: January 11, 2021, 06:58:15 AM »
No, they didn't.  The bike should have a Tillotson MT carburetor.  IMHO, unless you want 100% originality, buy one of the reproduction MT carbs. I've used 5 of these carbs now, and all run excellent.  They are made by Dennis Carpenter Cushman, also sold by our Simplex Source, Wayne Mahaffey.

https://www.ebay.com/itm/CUSHMAN-TILLOTSON-MT-STYLE-CARBURETOR-TOP-FUEL-INLET-806936-/273877231713?_trksid=p2385738.m4383.l4275.c10
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Rick

Gearhead-95

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Re: Zenith carb
« Reply #2 on: January 11, 2021, 07:18:19 AM »
I’ll take a picture of the zenith carb. I can’t find another one that matches it. But it is very very very similar to the carb you posted which is why I thought it might have been something they switched to in the later 50’s
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pd

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Re: Zenith carb
« Reply #3 on: January 11, 2021, 02:37:51 PM »
Welcome Gearhead-95 . :)

Post some side view pics of your bike .

Pete . :)

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Gearhead-95

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Re: Zenith carb
« Reply #4 on: January 11, 2021, 04:17:34 PM »
Here’s a couple pics of the carb. I can’t find anything like it. I will probably replace it with the carb Rick posted.
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Gearhead-95

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Re: Zenith carb
« Reply #5 on: January 11, 2021, 04:23:56 PM »
Here a couple pics of the bike Pete
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pd

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Re: Zenith carb
« Reply #6 on: January 12, 2021, 05:39:45 AM »
Ha . Just a touch crusty . Not real bad and plenty good to bring back . Same color as mine .
I see it seems fairly complete . I wish mine had a front brake .
I do like that fuel delivery system . ;)

As for the carb , it looks clean enough . I can't say I've ever seen one like it , either .
Don't give up on it , too quick . Have you taken it apart ?
What do the adjustment needle tips look like ? Still smooth conical shape or do they have some deflection ?
Does the float and it's needle function properly ? All passages clear ?

What are the frame and motor numbers ?
Motor # is on the left lower case and see the pic below for frame # location .

Pete . :)
« Last Edit: January 12, 2021, 05:50:02 AM by pd »
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Gearhead-95

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Re: Zenith carb
« Reply #7 on: January 12, 2021, 07:01:00 AM »
I pulled spark plug, poured a little heavy weight diesel oil in and splashed it around to lube up cylinder walls. Pulled side cover and inspected lower unit. Spun motor by hand and it felt good so I pulled the carb to inspect and clean it made new gaskets and put it back on. I hit it with a splash of brake clean and kicked it a few times and it fired up but will not stay running on two stroke mix
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pd

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Re: Zenith carb
« Reply #8 on: January 12, 2021, 03:12:21 PM »
Did you make sure the carb idle passage is clear by forcing brake cleaner through and seeing it come out where it's suppose to ?
Maybe the diesel fouled the plug ?
No air leaks allowed . ;)

Pete . :)
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