I think it's bent...

Merry · Post by **Merry** » Wed Sep 30, 2015 9:40 pm

Any ideas of the thread before I go and buy a tap and die set anyone?

Its a silver century Ws1613bb5

Post by **Charles uk** » Wed Sep 30, 2015 10:02 pm

Which thread are you talking about?

Horsley-Anarak · Post by **Horsley-Anarak** » Wed Sep 30, 2015 10:06 pm

1/4", 5/16", 7/16" BSF that covers it, other than the fuel tap and carb.

H-A

Merry · Post by **Merry** » Wed Sep 30, 2015 10:10 pm

Sorry I was supposed to add the pic

Horsley-Anarak · Post by **Horsley-Anarak** » Thu Oct 01, 2015 6:59 am

They do bend very easily on the CDI engines, I made a puller.
New crank time, you can try to straighten it if you have the equipment, but replacement cranks are cheap.
H-A

Merry · Post by **Merry** » Thu Oct 01, 2015 1:54 pm

Thing is I'm not sure if it is bent or the thread is shot, I'm going to try and re thread it first I think...

headdownarseup · Post by **headdownarseup** » Fri Oct 02, 2015 11:36 pm

Just a thought.

I've started doing this a lot now to all my motors.
When you re-build the powerhead and are getting ready to re-install the flywheel, i re-grind the tapers on the crank/flwheel with some valve grinding paste. Firstly remove the woodruff key, then apply a small amount of grinding paste to either taper, plonk your flywheel on and spin by hand for a couple of minutes until you have a nice even finish to the crank taper. The flywheel will end up being the same as a result. Remove ALL traces of paste before you put things back together for the final time.
Just makes things quite a bit easier to remove in the future if you ever need to. (less chance of bending anything)
AND it helps to really seat the flywheel squarely onto the taper for a good fit. (without any "wobble")

Give it a try, you might be surprised at how good things turn out with little effort.

Jon

Post by **Charles uk** » Fri Oct 02, 2015 11:47 pm

Seagull solved the wobble problem by seating the flywheel onto the crankshaft with a 10 : 1 taper & this question was really about a damaged thread, which H-A correctly answered, it's 7/16 BSF.

JERSEYMAN · Post by **JERSEYMAN** » Sat Oct 03, 2015 8:05 pm

I have had it before where only the threaded part of the crank was bent, as if it was clouted to remove the flywheel, once on the taper though and nut tight all was well with no flywheel wobble whatsoever, but then again why would there be, the threaded part is only there for the nut to push the flywheel onto the taper also I guess it stops the flywheel from being stolen

Saving Old Seagulls

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