Brother build.. 1986125xc/74 450cr

As the title states my brother and I have decided to build a vintage Husky.. neither of us know much of anything about dirt bikes, but he has a passion, and I'm slightly mechanically inclined.. or at least good with research.. We were told that we were buying a 1986 125xc, engine was in pieces but the bottom end is complete.. top end is missing studs and maybe a few other parts I haven't found out about.. every frame ID/engine ID list I've found says our bike is an 86 250xc, no big deal, but a 74 450/460cr engine.. first question, is there anyway to tell the engine size by looking at the engine?? Before we start buying parts I want to be as sure as absolutely possible I'm correct in it being a 74.. second question, shouldn't most parts for the 450/460 be the same? I'm guessing that to get the 10cc boost its a slightly bigger cylinder/piston on the same bottom? We're both rather new, and what I've learned has been learned the past few weeks reading hours on end.. any help would be greatly appreciated, as we want to do this build properly, and restore this bike back to, or as close to factory as we can

Just measure the cylinder bore and that should tell you the size of engine. The second question , is yes bottom end should be the same.
Whats with the 74 engine your post is a little confusing?
There is also a number on the 86 motor that you can look up as well (should be) unless some one took it off .

Show some pics of the motor.

Post pics of the engine stuff you have. There is not much of a chance that you'll be putting a seventies engine in the 86 frame without serious and pointless modification and fabrication. The seventies engines are all air cooled and you have a water cooled frame. Let's see that engine and all the vintage savvy guys on here should be able to help id what you have. This is the best source for any husky info and a lot of these guys have tons of knowledge. Welcome to the world of huskies and the forum

The reason I mentioned a '74 engine is because that's the year the engine ID number matched..

Sorry for the double post, this is all from my phone. As I said, I mentioned '74 because that's the year I found to match our engine ID. I'm trying to get pictures uploaded now. I found the bore size on the piston, but don't have anything to compare it too. We really are new to this. The guy we bought it from says he knows for sure it's a 125, and I'm guessing it is at least 80s because it's water cooled..

125 LC motor 84 +.

Thank you sir..

Next question, I can't find what size cylinder studs this bike requires.. main component that I've noticed is missing.. and we haven't been able to find a radiator for a 125, so purchased one for a 500.. I'm assuming that it should work, visually it looks identical, and mounting should be the same seeing as how the frames are the same for the sizes.

The engine is definitely an '84-'86 125. Impossible to find parts for that engine, which is probably why it was not rebuilt in the first place.

I would be interested in buying the engine if you want to sell it.

An after thought/question, brother wants to know if we can swap the cylinder/piston/head to a 250.. I know you can get big bore kits for newer bikes, but I'm not sure if this is to extreme a jump in size.. if it can be done, how big can we go? And back to the cylinder studs, if anyone can point us in the right direction it would be appreciated.. I've been on every website I can find searching by part numbers and have had no luck..

he should be able to swap in 250 and up motor and exhaust right?anything else unique to a tiddler?

Just the engine, maybe the radiators, as with all years prior the chassis is identical to the bigger bikes.

would be a smart move then, altho he would have to source a 250 or bigger replacement

get a 400...don't stuff about...

Would this piston be alright to use? Sides look good, only defect I see is its chipped on the top there..

no offense but i have thrown away many pistons that looked better than that.

80's 125 stuff is tough to find. trust me.

sugest finding a single shock water cooled 250 motor.

must be a single shocker water cooled though

exhaust routing and rear engine mounts will prevent a use of an earlier air cooled motor

I have a 85 cr 500 motor in pieces if interested. Cases are good. Tranny is a 6 speed out a 250. Could find a 5 speed for it if you wanted. It was torn down for inspection and rebuild but never made it back together. Pm me if interested and I can give ya more info. I'd have to check what size bore is as it was my fathers who is unfortunately no longer with us and I don't know a lot about it but can find out any info ya need. Just sitting in a box and I've got 7 other huskies that need much attention.

So we've ordered a few different parts, hoping we found studs that will work, got a new kickstart lever, and the internals for it.. anybody have any thoughts on Namura pistons? Besides a 200 dollar original with bad pictures, it's the only company we could find for a replacement.. I wanted the original, but money is a little tight..

I don't think Namura makes pistons for the 86 125 but I could be wrong.

namura makes any swede pistons??? would be news to all of us...