Cooling
After 31 years, the radiators are going to be a little on the worn side. You can't buy OEM, and original ones on EBay look terrible. I did some research and decided upon some GPI radiators. Yes, they are made in China but so are BMW's. They are made specifically for the YZ125K and are polished aluminum that's all TIG welded. You can get them directly from http://www.gpimotocross.com/. They are also a great bargain. In 2014 they are only $140 delivered for both! That's a bargain and i have read some good reports about them. The rest of the cooling system has to be assessed when she arrives.
Update: OK, take a look at the Winner radiators the the left. These are the correct ones for the YZ125K. Mounting brackets, radiator cap, hose connections etc.. all in the correct position. These are identical to the diagram i have uploaded on the technical page.
My first mistake of this rebuild is believing everything you see on the internet. The Partzilla.com diagram for the 1983 K shows the radiators for the 1984/5 L, N models. The same? No! The K has its cap on the left side and the rads are completely different. GPI only lists the 84/85 model and i assumed they would fit. I didnt check properly first! My fault and lesson learnt.
I contacted GPI and contrary to what i believed, they are not affiliated with Winner and dont have the K radiators. No problem. They asked me to return them together with my original K radiators and hoses. They will reverse engineer a set of rads for me and obviously they will then be able to make more for other customers. They will also make silicon hoses using my old hoses as a template. I hope to send everything to them soon and hopefully get some nice custom rads and hoses sent back. Keep an eye out for updates on this.
My first mistake of this rebuild is believing everything you see on the internet. The Partzilla.com diagram for the 1983 K shows the radiators for the 1984/5 L, N models. The same? No! The K has its cap on the left side and the rads are completely different. GPI only lists the 84/85 model and i assumed they would fit. I didnt check properly first! My fault and lesson learnt.
I contacted GPI and contrary to what i believed, they are not affiliated with Winner and dont have the K radiators. No problem. They asked me to return them together with my original K radiators and hoses. They will reverse engineer a set of rads for me and obviously they will then be able to make more for other customers. They will also make silicon hoses using my old hoses as a template. I hope to send everything to them soon and hopefully get some nice custom rads and hoses sent back. Keep an eye out for updates on this.
On another note, i read about a bloke who's YZ125L impeller had come loose from the impeller shaft and was not spinning. This meant it wasn't circulating the coolant and the engine overheated and seized. I saw a new OEM one going cheap so i decided to grab it and that will be going in for peace of mind.
Received a set of cheap original rads and hoses from America that are for the YZ125K. Below a pic of the rads with hoses attached next to the GPI polished rads. As you can see they are totally different. The GPI ones fit the L and N models and unfortunately someone on EBay is still advertizing the rads as fitting all 3 models. Both sets of rads, together with the hoses are boxed up and on their way to GPI to get reverse engineered so hopefully i will get some new good fitting rads back and also have some spares. They are going to make up silicon hose sets using the hoses i have sent as a base and i have asked them to make them in yellow and red. We will see what they come up with.
Finally, after a long wait, the radiators have been developed and i have the first picture.
Well, the new GPI radiators arrived so i have given them a trial fit.
Let me say, they seem reasonable quality and look great. All the holes
lined up and they fitted well. The original large rubber grommets that
are used to fit the rads to the frame need packing out as the original
rads have a 5mm thick tab that the grommets slip into while the new rads
are about 2mm thick. Easy adjustment. They also made up a yellow
silicon hose set from an original set i sent them ( i never got them
back ). They look good and seem to fit well. The have added a bit of "green" each end to
allow for any inaccuracies. Below are some pics of the rads fitted to
the frame and the new silicon hoses all fitted up. I have also trial fitted the
plastic scoop/shield things and the shrouds. They fit well with some
minor bending of tabs. The only downside is that the old rads had
prewelded nuts on the back of some of the tabs but the new ones dont.
I'm just glad that after 32 years, there is a replacement available.