1974 MZ TS250 losing power in high rpm

[Disszidens]

My 1974 MZ TS250 starts very easily and runs like a charm until I reach higher rpm, then it start to hesitate and stop accelerating further more. It sounds like misfiring and will not go faster than 52 mph. Same things happen in the 3rd gear at 42 mph - at the same rpm level.

I cleaned the carburetor and I have a brand new gas tank, new air filter new spark plug (NGK B8HS). Any thoughts what could be the problem?

[DAVID THOMPSON]

the points may look good but if they have been in the bike a long time..
the metal spring in them may have lost its strength or tension making them float at speed

I had this happen on a 1970 BMW that set 18 years ran fine below 3200 rpm/udm
miss bad above.. replaced points then it ran ok

dave

[Old Dog]

I am with Dave check or better change the points - if that doesn't work - check the coil.

[Disszidens]

Thank you guys a lot! I already ordered the points and a new condenser from Germany - great site: http://www.mzsimson.de/
I love this bike because a same model was my graduation gift from my parents in 1974. It brings back good memories and it is fun to ride!

I have been without a wife several times in my life, but never been without a bike!

[djsbriscoe]

Did you check the float level and the needle position? Also check that the fuel filler cap ventilation hole is not blocked. Do you have a haynes manual? Theyre worth having.

David.

[Disszidens]

Hi David,

Yes, I do have the Hayes Manual for the MZ bikes and it is indeed very helpful. The breather hole on the fuel cap is OK, I checked that and I checked the float position for closing (27 mm) and opening (34 mm) - right on the number. The needle is positioned as the Hayes Manual showed it, one notch exposed on the top. Is that right?
I checked the timing too and it was 3 mm BTDC. I believe it is the contact breaker spring being tired and not strong enough to push back the breaker at high RPM. I will let you know about the results when I received the parts and replaced the breaker points.

Too bad there are no MZ riders around my neighborhood...

[Old Dog]

I am surprised you are allowed to ride an MZ in California, I thought that 2Ts would be a definate no no with their pollution laws.

Get a factory manual there are errors in the haynes manual - like some of the torque settings - don't ask how I know this! Which one is it the TS250/1 5 speed or the TS250 4 speed

Best of luck with it and remember, on the internet everyone is in your neighbourhood

[Disszidens]

You know a lot about these MZs Dog, Thanks!

Mine is the old 4 speed original TS250. You are right about registering a two stroke in CA is a nightmare! I still have the Georgia plate on it and riding with that taking the risk with the vicious cops! It has to be 40 years old to get a "Classic" registration to put it on the road legally, that is the only way! It is a 1974, so I have two more illegal riding year before I can register it. Or, I could register it in the neighbor Nevada on my son's name who lives there...

Fortunately, I live in the country and I can ride on quiet mountain roads close to the Yosemite National Park. They are in great need of some good two stroke air pollution there! HaHaHa...

[Disszidens]

Hi Guys,

Thanks for Dave and Old Dog, yes, the problem was the tired out spring on the contact breaker points. I installed the new points and the bike runs great at any rpm.

I am all set for now... Riding towards the sun!

[Old Dog]

Well I hope that is the rising sun because the setting sun would be a short trip in California

[radiograf]

Don't forget to add a few drops of light oil to the felt cam wiper, as this will reduce wear of the plastic cam follower on the points, keeping the engine in tune for longer.