Rod interchange on MC125?
 

Hello all, new to the forum and gasgas which has led me here. I recently aquired what I believe to be a 2002 mc125 which was run on straight petrol, the rod is stiff on the crank (received it all in boxes) but the case bearings appear and feel good. The info I have found seems to concentrate on 250cc and trials, and on the 250cc I noticed rod was interchangeable with honda. Which makes me wonder if the mc125 and the cr125 were interchangable, or possibly the mc125 and ec125 part numbers for engine internals are the same? Any information is greatly appreciated. Also was wondering if anyone knows which digits in the v.i.n. indicate year. I would love to repair and ride this as it looks fun, but availability of part listings for the mc seem to be minimal. Thank you for your time

'98-'00 YZ125 rod kit should do it, as well as the piston kit from the same bike. Ours had a Vesrah rod OEM. Hinson clutch basket for a '99 Honda CR125 if you need that. The crankshaft itself is unique and expensive, so be carefull, have it rebuilt by a reputable shop. EC and MC are the same basic engine.

Don't fool around, replace the mains as well if the bike was run till it seized. Standard bearings and not that expensive. While its apart, replace the aluminum powervalve flaps with the steel parts and guides from the SM125 supermoto bike. The aluminum units had a reputation for breaking.

Rebuilt correctly its a very good, durable 125.

Thank you! Exactly the information I was after and thanks for the speedy response. I will also replace the main bearings, sounds like a solid recommendation. Thanks again for the quick response:)

While you have it apart have a look at the shift forks as well. Cheap to replace relative to the cost of one of them failing.

Paul B

The nice thing about the GG 125 is its built heavy duty like the bigger GGs. The shift forks are steel. In the '01 they looked perfect, as did the rest of the trans. The bike got a piston every year, a couple sets of reeds, and a clutch basket. Finally one main got loud so we rebuilt the whole motor.

The bike will run strong. Last race my nephew topped a class of full of KTM200s, in the mud, with my spare wheel that had a 120/100 tire and taller gearing that we swapped at the gas when he came in with a flat.