New Member 1974 MZ TS 250

[fmartone]

Hello everyone, I have an original 1974 MZ TS 250. It runs, sort of. I have problems with it fouling out the plug. I have ordered parts from Germany and England but I don't think I have the knowlege to make this bike run right. I know you have spark and fuel. I have the spark so it has to be a problem with the carburetor running to rich. I have taken that BVF carburetor apart at least five times trying to see what is wrong with it. Anybody in the group know of a good vintage MZ mechanic in Miami Florida? Thank you in advance for your help. Frank

[zedhead]

Hi there, the first thing I'd look at is the rubber disc on the bottom of the choke plunger (sometimes they crack up or come adrift). A related problem I had on my ETZ 250 was that the choke cable had slightly seized up, causing the choke plunger to be lifted from its seat in the carburetor all the time, irrespective of choke lever position. Keep us posted!

Good luck!

Karl

[manumensa]

Hello Frank!

I think you can find good MZ mechanics in the Miami cuban comunity. Thousand 2 stroke MZ motorcycle on the road today in Cuba.

Zedhead said and look also the air filter. Paper air filter only is good new after soon dirt close the paper pores.

Wellcome.
Best regards, Manuel.

[fmartone]

Thank you both for your prompt replies. The bike has 435 original miles on it. I will check the air filter, and that rubber seal where the Choke is sure sounds like it might be the problem. The bike actually spits black oil all over the front of the engine, that is how rich it is running. Is there a replacement seal available for that BVF carb? You guys are both great and I really appreciate the prompt replies.

[manumensa]

Hello!

"The bike actually spits black oil all over the front of the engine". Please, Can you explain to us more detailed?

"Is there a replacement seal available for that BVF carb?" Float chamber gasket available in internet MZ shops or you can made with joint-paper.

Saludos, Manuel

[iceman]

Hi Manuel,did you buy this bike ? Welcome

[Lamaha]

Hello mate,
Best advice from my own experience with my TS is to get a good carb cleaner.
If its stood for a long while the fuel in the carb etc can form a wax film that wont help.
Check jet and needles are clean and set correctly.
Most importantly keep the faith.
Best of luck from over the pond.

[manumensa]

Hello!
Beautiful filler cap !!

In the film On Any Sunday (1971)directed by Bruce Brown (USA) , we can see the Six Days in El Escorial (Madrid-Spain).

Saludos, Manuel.

[colm54]

Hi Fmartone, I realise this post is a little bit late and perhaps you have already solved your problems, but here goes anyway. Some things you should consider replacing are the HT coil, plug cap and ht wire, if you still have the original Isolator plug fit a B8HS NGK plug or even a B7HS with a .6mm plug gap. The HT coils on these bikes were made in Hungary or Poland and do not give a great spark at the best of times, replacing it with a comparable 6V Japanese one and a decent NGK HT cap will make all the difference starting, ticking over and running.

These 6v MZ's need a battery to run, if the battery is at five volts or less it will have to pushed to get it to run. Don't start it with the lights on.

The timing on this bike should be set at between 2.8mm and 3mm before top dead center, the point's gap is .3mm. Considering that the MZ is this age check the point's cam and ensure that there is no rust to cause the point's to close, check that the point's heel sits correctly on the cam when the engine is rotated and also that the point's contact's are clean and not pitted.

The BVF carb is fine, the usual problems are that 1, the float heights are incorrect, 2, it will not tick over, this is normal, they were designed not to. You can change this by drilling out the pilot jet from .35mm to .5mm and adjusting the cable by taking up the slack. Check that the air hose from the carb to the air filter box is undamaged, if it is cracked get a replacement from MZ-B or the usual sources. With some of the early BVF's just overtightening the carb mounting bolts could distort the carb causing the slide to bind in the carb. So check that the carb slide movment is correct.
Blipping the throttle when coasting down hills or when ticking over in traffic is recommended to lube the bearings. Pilot jet setting is 1 to 1 and 1/8 turns out.
Make sure that the choke cable is free and not trapped by the tank, remove the choke nut from the carb with a 14mm wrench, and check the round rubber disc in the end of the choke plunger. This can swell up and cause poor starting and poor running, sometimes it can drop out and make it difficult to start period. The plunger and cable should be adjusted loose. If the cable is set too tight, sometimes turning the handlebar can raise the cable enrichening your mixture and cause overheating.

Oil capacity is 750cc of EP80, the oil is drained from the 22mm drain nut under the engine and the bottom screw on the clutch casing, this recessed but usally comes out easily enough, most of the engine oil resides in there.

If you have any questions please drop me a line, I have worked on these bikes since 1971, I have owned these MZ twostrokes, ES250, ETS 250, TS250, TS250/1, ETZ250, ETZ301. I have worked on Simson S50 and S51B, and the TS125 and 150's as well. My MZ is 29 years old and still used everyday.