Hi, just bought my first project bike and already found the problem. For one the flywheel sprocket is missing teeth, and the starter gear holder in the case is broken. I know I need to replace the flywheel sprocket, but how do I fix where the starter sprocket is held? Can I take it to a machine shop? Here are some pics. Bike only has 700 miles on it. I'm in 850 right now. The current plan is to get everything else on the bike 100 percent. Bump start it make sure everything works and rides well then fix the electric start. But I have it apart now was curious how to fix it.

Pics

https://i.imgur.com/QbQ9hkN.jpg

https://i.imgur.com/J91xu0B.jpg

https://i.imgur.com/O2efWTY.jpg

Ouch!

Im thinkin a set of used cases is cheaper than the welding and machining you would need to fix that.

Ouch!

Im thinkin a set of used cases is cheaper than the welding and machining you would need to fix that.

What would the labor be like to replace the cases? I found both cases on eBay for 80 dollars.

If you are payin someone else to do it, your only cost effective choice is to buy a used engine and replace it altogether. Im guessing itd be near $1k to have a pro change the cases.

Changing an engine isnt that tough. No special tools needed really.

If you are payin someone else to do it, your only cost effective choice is to buy a used engine and replace it altogether. Im guessing itd be near $1k to have a pro change the cases.

Changing an engine isnt that tough. No special tools needed really.

Can you find a source I can reference on the procedure to change out the case from start to finish so I can get a gauge on how hard the process will be?

The factory service manual is what you want. Google "ex250 service manual pdf". For the second generation 250, theres a fuel injected version and carbed version if the service manual.

I ended up having to get a puller for the rotor and impact gun for the clutch and sprocket nut.

If you buy a set of cases, make sure you are getting a matched set. Half the ebay sellers are selling just the upper or lower but they are machined as a set and meant to be used as a set.

The factory service manual is what you want. Google "ex250 service manual pdf". For the second generation 250, theres a fuel injected version and carbed version if the service manual.

I ended up having to get a puller for the rotor and impact gun for the clutch and sprocket nut.

If you buy a set of cases, make sure you are getting a matched set. Half the ebay sellers are selling just the upper or lower but they are machined as a set and meant to be used as a set.

Should I just use it by bump starting it from now on? I probably should go ahead and clean the carbs and get it started to make sure it works and ride it around for a little before I consider getting new cases.

I cant help you one way or another on that. Im curious to know how the starter gear breaks like yours did.

If you try to start it up as is, you run the risk of those broken metal bits getting stuck in a bad spot and wrecking the internals. So definately find all the metal bits first and make sure the crankshaft and sprocket turn freely.

I cant help you one way or another on that. I'm curious to know how the starter gear breaks as yours did.

If you try to start it up as is, you run the risk of those broken metal bits getting stuck in a bad spot and wrecking the internals. So definitely find all the metal bits first and make sure the crankshaft and sprocket turn freely.

Think it happened by the sprocket getting out of line and just snapped it. Maybe by hitting starter when engine was running? It could have been my fault as I tried to bump start it when I got it to make sure the engine wasn't seized idk. Finding all the metal pieces is easier said than done though. I found some, but do you think the rest would get caught by the filter?

There is a catch screen that would catch any larger bits before getting to the oil filter. Remove the little sump that has the oil drain bolt on it, the screen is right on top of it.

When I bought my 2008, it had sat for couple years. Carbs gummed up and in my attempts to get it running, I hydro-locked engine due to petrol leaking past float-valves and filling engine.

Went to crank and it had slow spin, caught 1-2 puffs, and made scratching noise. Result was 4 broken teeth off ring gear. I managed to find all pieces which had stuck to stator coils. Welded teeth back onto starter gear and it'a been working fine since.

Seems worse damage in your situation with broken cases. Personally I would have no problems welding case back together. But you may have difficulty finding someone qualified to do work. And cost may be prohibitive compared to used set of cases.

Might as well rebuild it in process with new bearings, rings and seals.

https://www.ninjette.org/forums/attachment.php?attachmentid=43449&stc=1&d=1501472630

https://www.ninjette.org/forums/attachment.php?attachmentid=43450&stc=1&d=1501472630

https://www.ninjette.org/forums/attachment.php?attachmentid=43451&stc=1&d=1501472630

When I bought my 2008, it had sat for couple years. Carbs gummed up and in my attempts to get it running, I hydro-locked engine due to petrol leaking past float-valves and filling engine.

Went to crank and it had slow spin, caught 1-2 puffs, and made scratching noise. Result was 4 broken teeth off ring gear. I managed to find all pieces which had stuck to stator coils. Welded teeth back onto starter gear and it'a been working fine since.

Seems worse damage in your situation with broken cases. Personally I would have no problems welding case back together. But you may have difficulty finding someone qualified to do work. And cost may be prohibitive compared to used set of cases.

Might as well rebuild it in process with new bearings, rings and seals.

Well update wanted to make sure that the bike first of would run with no major issues so I put the case back on, cleaned the carbs (what a pain in the A##) then bump started it. Carb still needs some tuning but rode it around with the choke on to make sure it got into the gears. Just when I went to put it away I couldn't get it into neutral but probably because I wasn't rocking it back and forth. But biggest problem still is the case, but I also could use some help figuring out the hosing as a bunch of hoses for gas tank overflow and carb vents etc seem to be missing so Ill ask here when I get back to working on it where some go. Also thanks in advance this bike is going to be super fun!