putting a rod kit in my 250R

[lightemup01]

I have never done the lower end in an atv motor and mine needs a new rod bearing. i can take it to a local motorcycle shop and have them do it but im a do it myselfer. with good mechanical skill and access to good tools is this something i can do alone or should i just but my lip and take it to the shop?

[RIDE-RED 250r]

Unless you have the tooling and know-how to separate a pressed together crank and more importantly, put it back together perfectly straight and square, take it to a shop that can do the job right.

Rebuilding a crank is not a do-it-yourselfer type of job... period.

[lightemup01]

alrighty id rather be safe than sorry with that any way. thanks for replyingto my questions to!

[GO OVRIT]

The dissasembly and reassembly of the bottom end isn't bad, but like Ride-Red 250r said, rebuilding the crank should be left to someone with the correct tools. You can buy a HotRods crank for not much more than the cost of having yours rebuilt. Plus if yours has spun in the crank bearings it may not be rebuildable anyway.

[lightemup01]

it hasnt gotten that bad yet, its just got a little knock and ive been riding it like that for a while

[RIDE-RED 250r]

The knock could also be piston slap if you topend is worn...

[El Camexican]

Bearing knocks on a roller crank don't last long. The damage that you can do if the rod breaks is not worth riding it like that. Have you removed your cylinder yet to check if the knock is your bearing? As Red Rider said, it could be your piston (or even a wrist pin). Do you know how to check roller bearings? If not let us know.

[El Camexican]

The dissasembly and reassembly of the bottom end isn't bad, but like Ride-Red 250r said, rebuilding the crank should be left to someone with the correct tools. You can buy a HotRods crank for not much more than the cost of having yours rebuilt. Plus if yours has spun in the crank bearings it may not be rebuildable anyway.

I don't think I've ever heard the term "spun" used for a roller bearing rod. That term usually refers to a plain bearing set-up when the little retaining bearing tab breaks off and the bearing and allows the rod to "spin" around the bearing rather than with it around the journal. When this happened the crankshaft journal (usually one piece) needs to be turned down and resurfaced and the rod replaced or re-sized and a new, thicker plain bearing with a smaller I.D. is used. However, on a roller bearing the crank is in multiple pieces called throws, ends, journals, cheeks, counter weights, pins (many mean the same thing) and can usually be pressed apart to allow a new rod, bearings & lower, or “big” journal. All this comes in a Hot Rods kit, so regardless of how bad the assembly is worn it can be made like new. These assembles can even be TIG welded after they are trued, but you don't need to do this for a stock or even mildly modified engine. Like Red Rider said, take it to a pro, it’s not something you want to learn without an expert standing next to you, but I suggest that rather than go to a bike shop, you find out where the local snowmobile guys send their cranks and cut out the middleman. If you really want a trick crank call Falicon in FL. It will cost you, but you’ll have a showpiece hidden in your cases.

[Xowner]

Could be counter balancer also......

[GO OVRIT]

I don't think I've ever heard the term "spun" used for a roller bearing rod. That term usually refers to a plain bearing set-up when the little retaining bearing tab breaks off and the bearing and allows the rod to "spin" around the bearing rather than with it around the journal. When this happened the crankshaft journal (usually one piece) needs to be turned down and resurfaced and the rod replaced or re-sized and a new, thicker plain bearing with a smaller I.D. is used. However, on a roller bearing the crank is in multiple pieces called throws, ends, journals, cheeks, counter weights, pins (many mean the same thing) and can usually be pressed apart to allow a new rod, bearings & lower, or “big” journal. All this comes in a Hot Rods kit, so regardless of how bad the assembly is worn it can be made like new. These assembles can even be TIG welded after they are trued, but you don't need to do this for a stock or even mildly modified engine. Like Red Rider said, take it to a pro, it’s not something you want to learn without an expert standing next to you, but I suggest that rather than go to a bike shop, you find out where the local snowmobile guys send their cranks and cut out the middleman. If you really want a trick crank call Falicon in FL. It will cost you, but you’ll have a showpiece hidden in your cases.

I was reffering to the crankshaft main bearings, not the lower rod bearing or the wrist pin bearing. The outer race of the main bearing is a press fit in the case. The inner race of the main bearing is a press fit to the crank on the flywheel side. Its a slip fit on the clutch side, but still has a small tolerance. Worn journals on a crankshaft can spin inside the inner race of the crank main bearing. While the journals could be tig welded and machined, its not really practical compared to buying a Hot Rods crank. As a side note, the clutch side of a HotRods crank is said to be(I haven't measured) .0005 larger than oem making both sides a press fit in standard crank main bearings.

[Dirtcrasher]

You need a 10 ton press and some indicators as well as telescopic gauges to check the side to side clearance.

A lathe helps too

[stroberts22]

I had a bearing going down in the crank and I procrastinated on fixing it and it ruined my top end. It let lose all the little needle bearings and it looked like a bomb went off.

[lightemup01]

i havnt pulled it apart and i cant tell what the lnocking is without having it apart, it just sounds more like a rod knowck to me. i have the pages in my book how to check for most. regardless id like to rbuild everything just for the assurance of when i put the esr kit on it that it holds together