1977 Peugeot 103 carb linkage problem

Mike Harmuth /

Aug 09, 2020 07:32PM

Hi Guys, new to this forum. I recently started working on a 77 103 that my wife dragged home 15 years ago so I know nothing of it's history. I did find a bunch of half assed "repairs" that I've been making right. The current problem is the throttle cable to carb connection. The throttle control was broken, brake lever gone, cables in bad shape so I replaced most of the stuff with new, but the Magura housing was a used part.

So now, when I try to twist the throttle, I only get, maybe, 20 degrees of rotation and it gets tight. If I unhook the cable at the carb (had the carb out for a good cleaning, the needle and piston (that's what it's called in an SU carb anyway) move up and spring back down freely from the wire hooked under the needle that crosses over the carb to the throttle cable side. With the carb disconnected, the cable moves freely as well, full twist action, 100 or so degrees of rotation. When they're connected, I can get full rotation only if I push the lever (U shaped wire) while twisting the throttle.

The cable is connected to the wire by a cable stop that just sits in the U shaped hook at the end of the wire (the way I found it). To me, it seems like as the cable gets pulled, it rides up the U and makes the angle to the cable housing end too sharp causing the drag. Am I missing something that hooks on the bottom of the U so the cable pulls straight? I'm attaching a couple of pictures. Ignore the nut over the cable, that was just used as a spacer between the wire clamp and the U to see if I could keep the cable from riding up. It's just hanging on the slack part of the cable now but the condition existed before I put that there, just to lazy to take it off and reassemble for this picture. Does anyone have a close up of how this cable attaches? Any ideas?

thanks

mike

Re: 1977 Peugeot 103 carb linkage problem

simon judd /

bobsimes

Aug 10, 2020 03:39AM

here you go, this should answer your questions. https://myronsmopeds.com/category/carburetor/gurtner/

Re: 1977 Peugeot 103 carb linkage problem

simon judd /

bobsimes

Aug 10, 2020 03:53AM

I always have this end of a cable ($1 store cycle brake cable) fitted in the u shape bracket on the carb and it has never slipped out.

hope this helps. simon

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 10, 2020 07:40AM

Thanks, I see the problem now, my U shaped clip is bent up 90 degrees like a shelf. From the parts diagram, it should be flat so the wire pulls from a lower position.

Now on to the starting problem. Hopefully, with full throttle available, that won't be a problem any more.

mike

Re: 1977 Peugeot 103 carb linkage problem

cheetahchrome . /

cheetahchrome

Aug 11, 2020 10:30AM

Odd that that wire actuator was bent. Usually the plastic cap will snap off.

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 11, 2020 11:50AM

I pulled it of the carb this morning and bent it straight in a vice. Full throttle pull now.

It looked like it was bent on purpose, there was a nice witness mark across the wire where I assume it was held while being bent. That's one reason I wasn't sure if it came from the factory that way.

Next step, getting it started. I've already disassembled and cleaned fuel system, including removing the petcock and carb, new fuel line. I replaced the spark plug wire end cap (old one was bare conductor taped on) and the plug. I had to add a taillight but I was able to confirmed there's spark. Compression is 90 PSI, now let's see if it runs.

thanks

mike

Re: 1977 Peugeot 103 carb linkage problem

cheetahchrome . /

cheetahchrome

Aug 12, 2020 10:27AM

Hmmm 90 psi is not great and kind of hovering on the fence of start/no start.

If it does start I would say run it for a little bit to get some heat and fuel on the rings then stop and pull the head and cylinder off to check that the rings are not stuck in the grooves. If they are free your golden but if they are not You need to pull the piston and clean/soak it till the rings are swinging easy in their grooves.

I say all this because though stuck rings will often let the bike start after 15 years it wont be long before the cut the cylinder all egg shaped and then the compression will fall away boo hoo.

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 12, 2020 11:01AM

Thanks, I'll let you know what happens next.

mike

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 12, 2020 02:33PM

All right still wouldn't start. Did another compression test, 95 PSI, then gave it a couple of shots of oil, went up to 128 so it's the probably the rings. I squirted some Marvel mystery oil and turned it over a dozen cranks of the pedal with the plug out. I gave it a few more squirts, put the plug in and will let it sit for a few days. In prep of (probably needed I suspect) pulling the head, I gave the bolts some penetrating oil so the next steps will go smoother.

Thanks for your input. I know engines in general but not too many particulars on mopeds.

Re: 1977 Peugeot 103 carb linkage problem

simon judd /

bobsimes

Aug 13, 2020 03:04AM

If you have a spark try a small syringe of fuel down the plug hole and see if it fires

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 13, 2020 07:44AM

I tried starting fluid, (I know it's not the best fuel for a two stroke) both into the carb with the throttle held wide open and directly into the spark plug hole. Neither method produced any results. Again, I'm assuming (sometimes a very bad idea) this was running when parked and any problems I see are the result of a long sleep. It's getting to the point, probably this weekend, where I need to open it up and take a look.

thanks

mike

Re: 1977 Peugeot 103 carb linkage problem

simon judd /

bobsimes

Aug 13, 2020 07:50AM

Are you defo getting a strong spark when kicking over?

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 13, 2020 07:56AM

Yes, I pulled the plug, connected it to the HT lead and wedged it under the compression release cable on the top of the head. Nice bright spark seen across the gap.

Whether it's firing at the right time is unknown, one of my assumptions is that it is.

thanks

mike

Re: 1977 Peugeot 103 carb linkage problem

cheetahchrome . /

cheetahchrome

Aug 13, 2020 11:06AM

If you reach in with a ink pen and feel for TDC then look at the rubber grommet on the stator where the plug wire comes out. If your flywheels timing mark is about 3/4-1" to the right of the center of the rubber grommet, then your timing is close enough to run.

Re: 1977 Peugeot 103 carb linkage problem

Mike Harmuth /

ofracer

Aug 13, 2020 12:13PM

Thanks, I'll check it out. I put a borescope, barely, into the cylinder and saw scoring on the walls. I pulled the jug this morning and it looks like the rings were frozen, now free. It looks like it was "recently" rebuilt or the odometer (exactly) at 1000 miles is correct, not much build up on the head, piston etc. I was able to wet hone the jug walls but I'll get new rings, they're scored (not gapped properly? around 1mm). The piston is scored as well, will see if that cleans up. Not too concerned about that, no sealing done there. Maybe PO ran it on straight gas?

Seems straight forward internally, re assembly should be easy. I'll post progress here.

thanks

mike

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