Motoplat Horror Stories

[socalmx]

Paul's comments regarding ignition failues caused me to flashback to my own experiences with motoplat reliability. In 1974, I was campaigning a DKW 100 in AMA District 37 desert racing. The DKW was a great handling bike with Betor telescopic front and Curnutt 4" shocks on back. What it lacked was performance from the stock B motor. After watching my brother walk away from me on his Harley Baja, I took a trip down to FMF for porting, .060 milled off the head, and a custom pipe. This transformed the bike into one of the fastest 100 cc Sachs engined bike racing at the time. I was soon to discover that the weak link was the ignition. First failure occured about 5 minutes after unloading my bike at a race. I was riding around to warm up bike and it just died. Even though upset, I was glad that it occured around camp and not out in the middle of the desert. The local shop tried to talk me into a points ignition but I went with another motoplat instead. This came back to haunt me when I was racing in the 1974 Check Chase. In District 37, this event was second only to Barstow to Vegas in importance. After racing for over 100 miles with only 60 miles to go, I was leading my class coming into the final gas pit. After shuting off bike to refuel, it refused to start due to loss of  spark. Needless to say I was happy with that at all!

These days I race my Penton twice a year at the Adelanto and Elsinore Grand Prixs. My past came back to haunt me when at Adelanto less than two minutes into the race, the bike started crapping out at anything over third throttle. I nursed it around and finished but once again the motoplat failed. I could easily put on a PVL ignition but prefer to keep the bike "period". I have accepted that failing ignitions are a part of the game.

[TGTech]

Grounding, grounding, grounding. I can't say that enough when you talk about the Motoplat ignitions. If you have one of the systems that was manufactured before January 1, 1974, then you probably have a bad stator, but if you have one of the "red wire" systems, you should check out the grounds, no, not just check them out, but redo them. Using an Ohm meter to "check" them out, will give you absolutely no idea if you have a sufficient ground or not. Ohm meters work on three volts, but the grounding system of the Motoplats, carry anywhere from 190 to 245 volts.

The Motoplat ignitions, depend on the mounting of the various parts, to carry the ground. If you have paint (especially power coating) rust, or corrosion, between any of the parts, then I can guarantee you, that you will have operational problems.

The Motoplats manufactured after the "watershed year" of 1974, were some of the most reliable ignitions made, IF you treated them right. If not, they can be just as unreliable as any ignition made.

Dane

[charlotte]

Hi,
Dane is correct about bad starting is due to a bad earth, if you have this problem when the engine is hot it usually down to the out put source coil. Over the years of being warmed up and cooled down the enamel on the windings gets fatigued and heat is the biggest killer of insulation brakedown, you get what we in the trade call shorted turns which means a short fall in out put voltage. This is easily remidid by having the ignition rewound, and yes this can be done I have been rewinding Motoplat igniton stators for the last 20 years.
Hope this info is of some use.
               Regards
                Steve.

[john durrill]

Something ,i think, that should be done when you clean up the ground connection is the use of a silicon type grease on all the metal and threads that supply the ground. Dane do you have something you could recomend for this that would work best for the enviroment our ignitions live in? Even waterproof wheel bearing grease is much better than no coating on the cleaned parts and connectors i believe.
John D.

[socalmx]

If I only knew then what I know now. Buying a new ignition on a part time work budget was tough. Thanks for the advice.

[tlanders]

Please read my "Thank you Dane" post of a few days ago. Cleaning the ground paths worked twice in getting motoplats to function again.

Teddy