New to Forum, DKW 125

[Patrick Maloney]

Hello all,

I have a 1972 DKW 125 MC. It sat in my basement for many years after receiving it as a gift. It had been ridden very little.

The piston was stuck but with gentle rocking and a lot of oil/time, I was able to free it up. Clutch was stuck too but I used a pair of pipe clamps and worked it free. Carb had evidence of mice and cleaned it out. The slide is pitted but now moves freely.Gas tank was a rusted mess. Filled tank with small gravel, strapped to garden tractor wheel. After 3 hrs of running, 98% rust free.

All back together. Good spark, Compression 90 psi. I'm guessing the compression is low because the rings are still stuck.

To confirm carb settings; My notes told me, small adj screw 1-1/2 turns, large adj screw 4-1/2 turns. The 4-1/2 sounds wrong

Will an engine start with 90 psi? I can't even get it to hit. I splashed a bit of fuel in the spark plug hole to see if that would help, but no.

Thanks in advance,

Patrick
Bloomington, IN

[slvrbrdfxr]

Patrick,
Welcome to the POG site. Lots of good guys here with a wealth of great information that are always willing to help. Since you mentioned that the bike had evidence of mice in the carb/airbox then my advice would be to pull the exhaust off the bike to ensure it is free of mouse debris. You would be surprised at how much stuff that mice can pack inside an exhaust pipe and if it's plugged up the bike will usually not fire or run at all. Good luck and keep us posted on your progress with the bike.
Dave McCullough

[Patrick Maloney]

Dave,

Good advice. The tail pipe on this machine is quite small. From the looks of the piston location it was up in the cylinder somewhat. So now i'm think what might be in the lower end! Hard to imagine a mouse would enjoy a crankcase to get all cozy.

How to insure the exhaust is clean? Air compressor basting backwards? Wire bent with a bit of a hook?

How close is the Penton to a DKW? I understand the DKW has a Sachs 125 cc engine.

When I was gifted this machine in 1995, I did manage to start it with a minor cleaning of the carb and fuel system. It acted as if it was staved for fuel and would only run for 5 min. Wait for the bowl to fill and she be off again. I feel bad for the poor storage over the last 19 years. The original owner had used it very little and still had the rubber strings on the front tires from where it was first injected. And at that time no rust at all. So now, I'm determined to get her running and get her cleaned up.

Thanks Dave, I'll check the exhaust.

Patrick T

[Keith May]

Hi Patrick,

My Six Days had similar problems with the carb. Turned out to be a plugged pilot jet. It had plenty of gas in the bowl but still would run out of gas. I cleaned the jet (very tiny hole) with a single bristle from a wire brush and problems all gone! Be very careful not to damage the pilot jet. Runs like a champ. Good luck.

Keith
Louisville, Ky

[Eric Lewin]

I think 100 is the minimum psi to run a 2 stroke. I would pull the top end and check things out, even if it had 100.

[Patrick Maloney]

Kmay/Eric,

I hope my carb issue is solved, I cleaned it well. But we will see once I get her running.

With regards to the 90 psi compression. This bike has really low hours so I don't think she has low values due to ware. Just guessing but I bet the ring are just temporarily stuck due to the piston was stuck in the cylinder.I think if I can get it to run, the ring will free up quick.

My thought is to put a bit of oil in the cylinder to up the compression. Then roll in down a long hill and bump start it.

Thanks for your help

[slvrbrdfxr]

Patrick,
Yes try to blow some compressed air through the pipe to see if its clear. I've found acorn shells, paper, cardboard and etc inside pipes before and actually had one Penton pipe that had so much crap packed inside that I wasn't able to get it completely clean short of cutting the pipe open. If you do find yours clogged then try a coat hanger or etc to try and loosen the stuff up enough to blow it clean. As far as similarities between the Penton and DKW, many engine and carb parts are interchangeable but other than that not alot else will swap between the bikes.
Dave McC

[Patrick Maloney]

Dave,

Confirmed exhaust is all clear. I think I have two possible issue, Carb and compression. I'm going to shoot some compressed air through the carb body to see if Venturi is pulling fuel. Then if all good, shoot a bit of WD40 in spark plug hole to boost the compression. I'm hoping that if I can get it to run, the stuck rings will seat properly again.

I have a long hill at the local boat ramp, 1500 feet. I'll trailer her over and see if I can bump start. I'm beat after a few min of kick starting. I think I'll get higher RPMs as well

The 1/27/19 Bing carb has two adjusting screws, any advice on the set places? General web searching tells me 1-1/2 turns is a good place to start for most carbs.
This engine has no choke, just the slide, a tickler and a lever on the handle bars that via cable lifts some type of plunger. The tickler looks to just push down the float. What position should the throttle and plunger be in for optimal starting?

Thanks again

Patrick T

[Larry Perkins]

You need to use the tickler till it overflows gas and then kick.  90 lbs. compression will make for a tough start and is below minimum.  Fresh it would be 135-150.  The lever on the bar is an enricher but the tickler is the way to go for starting.

[Patrick Maloney]

Thanks Larry

My finger are crossed. I should have pulled the jug when I had the engine off!