TY 250 A Crankshaft Repair/ Advice?

[Tillerman6]

8 hours ago, tony27 said:

I have am electrexworld ignition in my 250C, works well & easy fit but you're best to set the timing with a strobe light as per there instructions. 1 thing I did find was that the hole in the centre of the stator plate didn't clear the seal housing & I've had to have some minor turning done to correct this, did a 3 day event with it before I had the chance to sort that including checking the timing & it was great apart from some pinking climbing hills between sections due to being over advanced

Tony27, Thanks for that bit of info about the seal housing clearance.  I have my own lathe and mill, so I will look for that when I get the parts in. Not sure when that will be.

Then the next issue is to fiure out where they all go.  I didn't take the gearbox apart, so I didn't see the relationships inside.  Most of it is pretty self explanatory, but there is a good chance of getting something in there wrong or omitted.

 

 

[Junglejeff]

I will give you a good tip when putting motor back together.Remember to hook the internal kickstarter spring in the steel tube.I had to split my cases to do that because I forgot.It turned out the catch tab for it was bent a little so reaching thrue with long needle nose pliers did not work.It lines up the spring correctly when you install the kickstarter shaft.Been awhile but I remember the frustration. 

[Tillerman6]

On 5/31/2020 at 5:59 PM, Junglejeff said:

I will give you a good tip when putting motor back together.Remember to hook the internal kickstarter spring in the steel tube.I had to split my cases to do that because I forgot.It turned out the catch tab for it was bent a little so reaching thrue with long needle nose pliers did not work.It lines up the spring correctly when you install the kickstarter shaft.Been awhile but I remember the frustration. 

Junglejeff,

That's good to know.  I sure wish I was there when the cases were opened though.  Even with the factory shop manuals there is still some room for error.

it's just human nature to screw up.  For instance I spent two hours today trying to straighten out an order from Ebay.  I ordered a new crank pin with the original part number and the seller had written in pen on the bag the same number, but when the engine rebuilder received the "new part" it was wrong.  So I called them up and they said sorry.  You have x days to return the part for a credit.  So now the rebuilder has to take his time to mail something back before the deadline.  So I asked the supplier if they had the correct part - The guy that answered the phone said "No I don't show any crank pins in inventory" (Redline Motorsports) So that outfit is a bust.  So I found another supplier that has a good rep on Ebay for another new pin and we get to see if that works. Goo thing I'm not in a hurry. 

And I ordered a new Tusk puller tool - not sure if I will be the one to use it or not, but again, the company made another kind of mistake. They sent my tool to Mississippi instead of my address in Idaho.  How can that happen on Ebay?  So they sent me another one. That was good and I got it today.  But wait there's more! 

 

The puller tool is really beefy and well made, but on the TY 250A, only the magneto end of the crank can be pulled thru the bearing.  So the right side of the crank has to be a hot and cold kind of assembly procedure.  The tool is only good for the magneto end of the crank, and the instructions say to do that After the other end is seated.  So that means the right side cases will be already loaded with the crank inside (stuck there) and now we have to load the gears into he left side and try to line everything up and pull in the crank with the tusk tool.

That seems to conflict with the factory manual, as they have everything loaded into the left case first.

It's a little much for someone that has never done it before.  And the chances of screwing it up are about 90% I would think.

I don't yet have the dis-assembly tool, so that makes me a little paranoid about attempting the whole procedure.

[Junglejeff]

I made my own puller tools from some steel tubing but should have just picked up a tusk puller.We use yz rod kits (hot rods)for 89 to 98 yamaha.Everything the same except small end is 1mm bigger. I use a 1980-82 yz wossner piston in mine and it comes with proper bearing for later rod.Piston is arc  cut on back instead of intake windows but timing is the same as window piston. On the right side of crank there is a o ring that seals the pto gear to crank.keeps you from cross contamination of tranny oil and crankcase mixture. In most bearing kits the o ring is to thin.Reuse old or get a new one from yamaha.Very important o ring as it keeps your tranny oil out of crankcase. I re used old one and gave it a smear of yamabond 4 to make sure I had no issues.I use parts houses on line to look at parts break downs for assembly. They often make it easier than using a manual.