So my 250r threw its chain today.... PICS

[k00leo]

Well i have been trying to jump my 250r off a few naturally made jumps on the farm. Nothing crazy, just a foot or two off the ground. I was riding up a slight hill gaining speed to a jump when all of a sudden i heard a loud rattling noise and then lost all forward movement. I immediately killed the engine and looked down where the chain is suppose to be. Nothing was there. I freaked out a second and looked at the engine case where the front sprocket was. The case was chewed up pretty bad but NO CRACKS. Since there are no cracks in the case, i should be fine, correct?

Thank god that I've done my research. The first thing i bought for both of my 250r s was a case saver :) I read that they were notorious for throwing chains.

http://img.photobucket.com/albums/v310/k00leo/IMAG0487.jpg
http://img.photobucket.com/albums/v310/k00leo/IMAG0488.jpg
http://img.photobucket.com/albums/v310/k00leo/IMAG0489.jpg
http://img.photobucket.com/albums/v310/k00leo/IMAG0494.jpg

Few questions...

what really causes a chain to throw or snap. In my case, the chain snapped. Is it a loose chain? or an overly tightened chain? I tightened the chain first thing this morning. It wasn't too tight though, there was still some wiggle in the chain. I suspect the chain was just worn, stretched, old, etc. and that is why it snapped.



I want to get a few front sprocket, i have 13T on it now. To gain some low end, i can change the front to a 12T correct? Will i notice a difference? would it be too much of a difference?

[three_wheelin45]

Well heres a little info I know, If chain is to loose it falls off easyer and wears out your sprockets. To tight It will snap and also be hard on your sprockets. Also keep in mind that when you sit on it it makes the chain way tighter. So when you are adjusting your chain make sure someone is sitting on it. Just my $.02

[k00leo]

Makes sense, thanks.

[three_wheelin45]

No problem :D

[jrsqlc]

Well heres a little info I know, If chain is to loose it falls off easyer and wears out your sprockets. To tight It will snap and also be hard on your sprockets. Also keep in mind that when you sit on it it makes the chain way tighter. So when you are adjusting your chain make sure someone is sitting on it. Just my $.02

Nicely stated!!

[RubberSalt]

Get a chain tension, or make 1. Nice to always have a little tension on the chain, less likely to falling off, really nice when jumping and the chain moves alot.

[ceaserthethird]

That Front Sprocket is installed WRONG !!!

The Spacer Side goes faced in ( againest the Motor )

That's why the CHAIN rubbed the Cases...

I see this All the Time...

[k00leo]

That Front Sprocket is installed WRONG !!!

The Spacer Side goes faced in ( againest the Motor )

That's why the CHAIN rubbed the Cases...

I see this All the Time...

:eek: whoa really? I will make sure to put it on correctly.


Can anyone answer my sprocket questions?

[Thorpe]

Dropping 1 tooth on the front sprocket will give you noticeable lower end gains... I feel it makes the power more manageable...

[Mosh]

Looks to me like you need a massive round of drive maintenance is needed from those pics.

The sprocket is backwards.
You are missing a front chain slider on the swinger.( are you missing any other chain rollers or are they in bad shape?)
All that crud looks to need attention.
You need to check your swinger bearings and rear carrier bearings.
If there is any play, they need replaced.
Buy a good O ring chain and sprocket kit, and slider/roller kit, and fix all these items now.

It may seem like a lot of money, but cheaper than a new engine case.

[k00leo]

Looks to me like you need a massive round of drive maintenance is needed from those pics.

The sprocket is backwards.
You are missing a front chain slider on the swinger.( are you missing any other chain rollers or are they in bad shape?)
All that crud looks to need attention.
You need to check your swinger bearings and rear carrier bearings.
If there is any play, they need replaced.
Buy a good O ring chain and sprocket kit, and slider/roller kit, and fix all these items now.

It may seem like a lot of money, but cheaper than a new engine case.

Oh i agree.

All the bearings on the bike seem to be fine. There is no play that i can notice. I do need to buy a front chain slider, new chain, new front sprocket, new back sprocket. Once i do that, i will believe i will be good to go.

All that crud that is on the bike is from my recent trip to my buddies place. :) She's a rider. Good times.

[leviblue]

alot of good advice here.... your very lucky it didn't bind and crack at the shaft

[k00leo]

The shaft, are you referring to the shifting shaft?

[aldochina]

the drive shaft that the sprocket is mounted to!!

[leviblue]

The shaft, are you referring to the shifting shaft?
yep...it binds up in there and backs-up inbetween the casesaver and the shaft and pop there it goes. you've got a split the size of a plumbers crack. if or when you rebuild your motor get someone to put a bead on the grind and smooth it out. your very lucky that is a $300 part....I think there is one on the site 4 sale and you'll see how lucky you are. It's happend to me a few times you just gotta check your chain and rear every time you go out. I replace mine twice a year on my riders and though it may seem over kill the bikes average 25 hrs a week riding time so it's cheaper than a new case

[Dirtcrasher]

Aside from the backwards crap and maintenance issues; One of your pics shows where the chain freewheeled for a bit and a hole in the case. Almost looks like the back of the countershaft bearing OD where it seats or something in that area.

250R's have lots of travel. They have to have good chain/sprockets/bearings and an adjusted chain. Like stated above, too tight snaps the chain (usually at the master, is that where yours did??) and too loose falls off etc.

I hope it's AOK but you may wanna slap some JB weld on that one area I see. If I knew how to put it in Microsoft Paint and point to it, I would, but you should be able to see it...........

[acidburn]

is this the hole trailprotrailpro talking about DC?
http://img405.imageshack.us/img405/3568/holet.png (http://img405.imageshack.us/i/holet.png/)

Uploaded with ImageShack.us (http://imageshack.us)

[Dirtcrasher]

Yeah, thats the one concerns me a bit........

25 lashes are in order for lack of maintenance :lol:

[Red Rider]

That Front Sprocket is installed WRONG !!!Not necessarily. Without seeing both sides of the sprocket, you can't tell for sure. If the other side of the sprocket is completely flat, then it is indeed installed backwards. I have a few sprockets that have a spacer on both sides. In that case, the small diameter spacer goes against the engine, and the large diameter spacer faces out.

[k00leo]

I've looked closely at the above mentioned area and it seems that it didn't punch a hole through the case, just chewed it up a little bit. All seems well. I may throw some JB weld on there though I'm not sure that i really need to. I've sanded it down pretty good so it doesn't look nearly as bad now.

The plan now is to get some engine degreaser and clean up the bike a little bit. Get some of the grime off it. I haven't given it a good washing in a month since school has kept me busy.

I ordered new sprockets and a chain yesterday and I'm looking forward to putting them back on the bike and seeing how she rips.


Thanks for all the help and advice.

[200XMichigan]

Might want to keep that other 250R. Chewed up cases suck. Check the chain at least every week. It doesn't take more than a second to check the slack on it. And when the teeth on the sprockets start looking all chewed up its time for new stuff before something gives.

[k00leo]

After it being cleaned up, it is not really that bad at all. I'm Going to do a little more sanding and then just throw some spray paint on it for now. Once the Sprocket is on there you will never know it happened unless you either saw this thread or were looking directly behind the sprocket.

I'm not really getting rid of the 250r if i am looking to trade for another though, now am I? :Bounce haha

[k00leo]

Well i cleaned up the motor a little bit with some engine degreaser and then i painted the the bare metal. It doesn't look too bad at all.

You can see where there is a small crack where the case saver is bolted. That was there before the thrown chain. Its not bad at all. Doesn't go deep at all.

http://img.photobucket.com/albums/v310/k00leo/IMAG0498.jpg


Anyway, i'm just glad there isn't any substantial damage, just more an eye sore. I will post another pic once i get my new sprocket and chain.

I think over the summer, when i don't take as many college classes, i might rebuild the entire thing. I haven't decided yet though.

[200XMichigan]

Make sure to get chain sliders too. Otherwise you can do damage to the swing arm letting the chain slap the crap out of it all day long. Looks a lot better cleaned up. What is that weird tape junction on the clutch cable?

[k00leo]

Yep yep, i have a chain slider on order to, NOS.

That weird tape junk is some kind of adhesive tape that the PO put on there to prevent water from entering unwanted places. Its on the bike in different places as well. I hate it. I need to take it off.