Big End Bearing


New member
Hi guys new here :) From the UK!

I picked up a 2005 EC 250 about 2 weeks back. Within the first few hours of riding the little bugger siezed up :( After it cooled down it unseized however made an awful clatter.

Anyway I removed the engine and dumped it with a mate. He has split it and the main bearings are shot. So I will be replacing these and seals and a new piston kit as it is looking worn.

He said the big end bearing appears ok but could replace. I thought why not. However am I right in thinking you cannot just replace the bearing you need an entire new rod kit at a heft cost?

Is there anyway round this? Reason why this bearing is not sold seperate?

Whats the view if it seems ok leave it? To be honest I am on a kind off budget due to getting married next year. Had I not have been I wouldnt have thought twice. I had to work hard enough to get permission to buy the bike in the first place.
The rod uses the crank pin for the inner bearing race and the rod itself for the outer race. So if the roller bearings go bad they grind up the pin and rod.

If the main bearings where shot more than likely the rod is not far behind as the rod sees a more load than the main bearings due to the smaller amount of surface area of bearing.

Might have to check ebay for a rod kit. The other way to look at it is the crank is already out on the bench. If the rod bites the big one you will be buying the main bearings again plus gaskets and labor.

Good Luck on the Wedding.
Replace the rod and get a little peace of mind. I would also suggest getting all yours toys in order before the big day.
Might be worth considering why this might have happened. The Gasser bottom ends are usually pretty robust. Could be as simple as a torn filter or a drowning but have a check over. It's also easy on these bikes for the airbox not to be sealed on the carb properly.
Thanks for the replys guys.

I started another post regarding if a rod kit from a CR250 would be suitable? It states in the cross over that it is. I can pick one of those up for a large amount less. Would it be suitable?

When I took it apart the filter seemed in good order and there appeared to be a good seal when I removed the carb rubber. I checked it to make sure it was not torn and all seemed well.
Its probably the same rod sold as OEM. Mine last two bikes had the Vesrah rods in them.
Yes Honda rod will work.I use the pro x rod kit there are other choices as well. There were some quality control issues with the hot rod kits we experianced a while back so I avoid them .There is also some stuff coming out of India which has a decent rep but for the few dollars more I'll stick with the proven Japanese stuff.
This has been recently discussed in another thread. Same rod kit for a Honda CR250 fits 200/250/300.