1971 SL70 flywheel key issue

S

stone

New Member
Hi,

I'm new to this forum and I hope you guys can help me out. I have a 1971 sl70 that has no spark. So I thought I would pull the flywheel to see what's what. When I took the flywheel off I noticed the woodruff key was smashed. So I ordered a new one plus some points and a oiling pad. I got the new key and its too small depth wise. The key barely sticks up above the crankshaft. And the flywheel turns and the key doesn't fit in the slot. So, either I looked up the wrong engine or the website is wrong. The part I ordered was Honda part number 90741-035-000. Which through some research fits most of these old 72cc minibikes. My question is, what is the other key that fits these engines. My engine also says model: SL70E if that makes a difference. Thanks in advance for the help.
 
That’s the right part number you ordered. Keep in mind they don’t stick up very high as the key way is just for flywheel alignment. Pics of flywheel and crankshaft slots will help sort this out. Do the points open if you line the slots up and tighten flywheel down without a key? I’ve run bikes without a key before.
 

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I don’t know. I’ll give it a try. But the old key even know it’s a little smashed mic’s at about 3.7mm the new key is 2 mm. I would think the proper one would be 4mm. I’ve worked on a lot of engines in my time but not this type. I’ve never seen such a small key like that. It just seems like the wrong key. Not enough meat to not smash and lose time and spark.
 
CLEC66 said:
That’s the right part number you ordered. Keep in mind they don’t stick up very high as the key way is just for flywheel alignment. Pics of flywheel and crankshaft slots will help sort this out. Do the points open if you line the slots up and tighten flywheel down without a key? I’ve run bikes without a key before.
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I tried it and it seems to work. Set the new points and have spark now. Thanks.
 
CLEC66 said:
That’s the right part number you ordered. Keep in mind they don’t stick up very high as the key way is just for flywheel alignment. Pics of flywheel and crankshaft slots will help sort this out. Do the points open if you line the slots up and tighten flywheel down without a key? I’ve run bikes without a key before.
Click to expand...
CLEC66 do you happen to know the flywheel torque spec? I have a manual but it doesn’t seem to say in there.
 
My Clymer manual goes by bolt size and thread pitch. I usually snug down with impact driver but you definitely don’t want to strip those crankshaft threads.
 

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