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Another Autolube thread. But different. I swear.

16 Feb 2020 16:41 16 Feb 2020 17:12 by wierzbarecording. Reason: New information
wierzbarecording
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Another Autolube thread. But different. I swear. #1
I just poked around in the search for a bit, and could not find an answer.

DT3. The oil pump had a cracked gear. Started pulling the pump apart, and realized that the teeth were all messed up in the inner gear.

I bought a new oil pump on ebay, guy claims its pulled from a dt3. Everything is all good, pump looks great, and looks identical to my old one. I was going to reuse my shaft. Then I realized the worm gear and inner gear are actually way different from each other. The one I pulled off is much coarser on the worm gear and while I can get the worm gear on the old one to spin, I would not trust it in a build, but it actually seems to spin the pump much faster than the new pump spins.

The old one is a 40:1 shaft vs pump, and the new one is 55:1.

What's the deal? Less oil flow? I have an MX/CT pump for one? Who knows?

Kyle
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16 Feb 2020 18:18
MarkT
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Another Autolube thread. But different. I swear. #2
Pumps all look the same... they had a colored paint dot code (often missing) and sometimes a pulley number to ID and even then it can be a mystery as to what a pump fits... especially the earlier models where the manuals are sparse on information.

You probably need to be an expert like DEET to figure it out... DEET might be able to help you get a good working pump out of the two you have or maybe even the original can be fixed. Would be worth a try to contact him... It often saves money to send what you have to DEET rather than buying an unknown or even "NOS" pump... what you get back will be gone through and will work.

Good luck!

1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250

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16 Feb 2020 19:32
Makotosun
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Another Autolube thread. But different. I swear. #3
One interesting thing I discovered during my MX360 build is that the 73-74 MX’s used both a pump AND premix per the owners manual. The pump is definitely a different pitch than a DT as well.

Just one of those weird unique bits of info.

IF it isn't one thing, it's another.

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17 Feb 2020 05:38
Eazy-X
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Another Autolube thread. But different. I swear. #4
Only recently got into this whole "autolube culture" :D From what I've seen (from the '70's era) there seem to be either fine-toothed gear, small stroke-diameter rod pumps versus coarse-toothed, wide-diameter rod ones. I would imagine the volume output could be comparable. Even if they were interchangeable (assuming you have the drive shaft and plastic gear that sits on the inside of the engine) you'd have to at least mess about with the shims on the pulley... all sounds very complicated!

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