7900 coil swap

[Poleman]

That's correct Randy. That way you can always go back to correct crank/flywheel set as original. The big thing to me is the little crank mark for TDC an the noted location. The flywheel can be positioned from there. Even removing the flywheel after mod just set the crank for TDC and reposition flywheel to desired location again.

 

[Mastermind]

I've been waiting on the new unlimited coils for awhile on a few saws. I think I'll go ahead and do this on a couple. It looks like you are using the aftermarket 272 coil. Have they been working well?

 

[Poleman]

Yes, Crank, flywheel and case all line up initially to case mark....then flywheel is advanced 30 degrees from there. You can as I have once proper timing is found and tested remark the flywheel can be marked again showing the location at advance.....just makes reinstallation quicker and if you send a saw out marks just need to be lined up to be correct again.

 

[Poleman]

Yes...I use and after market coil and haven't had any issues with them. I find AM to be a cheap alternative for everyone to try if they wish, just like the AM carb mods. Not sure what an OEM coil would be like as I've never tried one.

 

[Poleman]

It should all look like this when everything is right....If you look close the crank it still on TDC mark at the back of the case ant the fin is on the 30 degree mark. This helps me explain as I am visual...lol

 

[Miller Mod Saws]

Thanks rich! I wanted to throw this our here. In this pic Rich shows the mark on the flywheel and the cases. I actually just grind the tip of that fin to a point. Just the upper little corner so it can always be found!

 

[Miller Mod Saws]

And I grind a line at the 30° point. So it can always be found.

 

[Miller Mod Saws]

And the last couple I made taper and broached it so the customer never had to worry about getting it right if they pulled the flywheel!

 

[Gravitas]

I've been waiting on the new unlimited coils for awhile on a few saws. I think I'll go ahead and do this on a couple. It looks like you are using the aftermarket 272 coil. Have they been working well?

I'd be fine with that, just sayin'...........

 

[DrewUth]

I read someone saying that they were having trouble keeping the flywheel in place without the key (it would slip). Working on vintage dirtbikes and frequently having to swap ignitions from one bike to another, I have had to time many without the keyway (some 180* off!). I use valve lapping compound between the flywheel and the crank to make sure the taper fit is spot on- load it up with compound, work it back and forth a dozen times (rotating it 90* or so), lift off, rotate 90*, put it back on, repeat 4 times or so. Then clean everything real good, and you'll be able to see just how good the taper fit is by observing the dull or shiny spots. As a last ditch resort, a little blue loctite can help take up some low spots in the fit and hold it on there. Hope my ramblings make some sense!