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TOPIC: 1970 At-1 125 Enduro Newbie Here!

1970 At-1 125 Enduro Newbie Here! 16 Mar 2019 21:11 #1

  • shelz1209
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Hey Everyone!
I just got a 1970 125 Enduro and I have a few questions. Well she runs, but only barely. Here’s what I at least know needs to be worked on: I know the carb needs cleaning, but I can’t get it off because the bolts are rounded off and all seized up. It needs a new air filter, the kickstarter only engages every now and then (I don’t have a clue what to do, or where to start with that) and the oil pump isn’t even connected to the oil reservoir. The guy I got it from just said it had never worked since he got it. I also suspect it will need a new voltage regulator before long. I don’t know how to tell, but it’s the original, so it can’t hurt to replace it, i figure. The electric starter seems like it needs work. It only works 1 time and won’t work again, but the battery is still charged after the starter stops working. I want to get some replacement parts, but I don’t know who to trust and what will actually fit or work. If anybody has any ideas or suggestions on any of these repairs or parts I would really really appreciate it. I’m super excited about this bike and can’t wait to get her on the road. Her name is Lucille, by the way, because she’s red and a little funny.

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1970 At-1 125 Enduro Newbie Here! 16 Mar 2019 22:15 #2

  • Mothersbaugh
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Are you sure it's not a 71? The 71's were brilliant red. Check the VIN listings here on the site to be sure.
On the carb bolts, don't force anything. Try your favorite solvent for a while first, even for a few days. Tap gently with a hammer every now and then. Sometimes it works to try breaking them loose by tightening them slightly, then reversing again. But take your time. Clearly there are all sorts of other things to do while you are waiting and working on those bolts. Try heat if you are sure you're not going to set the thing on fire. A heat gun for a while may cause the metals to expand at different rates, and that can free things up. A small pipe wrench? A pair of Visegrips as a last resort if you have tried everything else? Completely rounded off, the bolts are?
The voltage regulator is still available. Sit down before you look at the price, though.
www.partzilla.com/catalog/yamaha/motorcy...t1b/electrical-at1-b
Partzilla is one place for parts; your local Yamaha dealer is another. Speed and Sport, and Rocky Mountain ATV and Motorcycle (RMATVMC) are two more.
The kickstarter is not a terrible problem. You'd have to drain the transmission (make sure you get the right bolt underneath the motor; the other will have parts falling out if you open it up) and open the right side case cover to get at it. There is a lot of info on here about the common kickstarter problems and the redesign which beefed up that unit.
In the tech library in the toolbar across the top of this site, there is a drop down menu of manuals you can access and download. Those are worth your time to study and decide how you want to go about things.
And replace the brake shoes, as the old shoes may have de-laminated and can cause the front wheel to lock up at speed, throwing you over the bars. They are not expensive and one of the easiest repair jobs.
Welcome. Ask away after reading and searching to get yourself started.
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Last Edit: by Enduronut.

1970 At-1 125 Enduro Newbie Here! 16 Mar 2019 22:55 #3

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Thank you so much! It was originally yellow, according to the PO, bull I’ll check the vin just Incase.

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1970 At-1 125 Enduro Newbie Here! 17 Mar 2019 06:17 #4

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Originally yellow is correct for a 1970.

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1970 At-1 125 Enduro Newbie Here! 17 Mar 2019 08:13 #5

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Purchase a service manual and send some “distress smoke signals to Capt. Dave” would be my best advice ...

Welcome

a

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YAMA-LAND
818-521-2109
MINIBIKESERVICE@AOL.COM 1971 125cc AT1-C (DOROTHEA) 1971 175cc CT1-C (BRANDY) 1970 250cc DT1-C (MONICA) 1973 100cc Hodaka Combat Rat (ABBY NORMAL) 1975 DT400 (BONNIE BELL)

1970 At-1 125 Enduro Newbie Here! 17 Mar 2019 08:32 #6

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Welcome!

The regulators are pretty tough. If it's working, it probably is fine... maybe needs cleaning and adjustment?

There are several factory service manuals available in the Tech Library here that describe the operation, maintenance, and troubleshooting of the 125 starter/generator.

I say several, because the same basic system was used from 1969-1976 in the USA so the "theory" is the same and the manuals sometimes change a little how they say things. So reading the different manuals (including the generic 1969 Yamaha Shop Theory Service Manual) can help gain understanding of how the system works. The exact manual for the 1970 is also available.

Checking brushes and commutator might be a good place to start?

Here's a couple to get you started.

yamaha-enduros.com/index.php/workshop/se...69-yamaha-shop-guide

yamaha-enduros.com/index.php/workshop/se...at1-b-service-manual



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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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1970 At-1 125 Enduro Newbie Here! 17 Mar 2019 17:46 #7

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You could also call Yama-Land Restorations. They are quite knowledgeable and know these vintage Yamaha's through and through!
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