Hi guys,

I posted on here a few days ago about building a NC30 race bike. I brought a engine for a absolute bargain with the problem being a suspected bottom end bearing failure. The lad I brought it off said that he'd rang round a few engineering workshops and from what he described to them what happened over the phone, they all said it sounds like the bottom end bearing.

Now winter is here my plan is to rebuild it. With it being a suspected bottom end bearing that is the first place I'm going to. The only thing I'm thinking about is, Can or is it a straight bearing swap? Or will I have to check it hasn't thrown the crank out of balance and make sure it doesn't have any run-out? Last thing I want to do is replace the crank bearing and run it for it to still go bang!

Any comments welcome

Many thanks.....Cal

Bit hard to say without seeing what's inside, the state of the current bearings and the crank bearing faces.

Hopefully the faces haven't picked up

When you say picked up Timon, do you mean its like welded itself to the crank?

Many thanks mate.....Cal

Picked up debris and scored into the face

Ah wicked, I'm with you mate.

Yeah I hope not, I'm praying that its just trashed the bearing so its a straight swap for a new bearing.

Cheers....Cal

Best is to set the diagnose by starting the hart surgery on that engine, and then tell us what you found. You being the doctor so post some photo's up here since there is a ton of expert lads here on this forum to help you and your patient

Cheers Micpec!

I'll be taking loads of photos while I'm doing it, so that shouldn't be a problem. I'd like to think I'm fairly mechanically minded and that I'm not bad with a set of spanners (I have enough of them!) Its just when or if things get a bit too serious in the engineering department, as I'm limited on tools and equipment in the size of garage I have.

I'm not planing on doing a rush job either as I like to be patient with jobs like this so nothing goes wrong. I'll probably start a project thread on the engine/bike build just so its all there to see.

Many thanks again mate!

Cheers....Cal