Lightening an E-start flywheel

[Gutty]

Took my flywheel off yetserday and gave it a shave down on the lathe.

Figured it would be worth posting a bit of info for others.....or atleast pitboss/thumpy 110 E-start owners.

First, this job will be much easier with a rattle gun, other than that you need to buy a flywheel gripping tool.
Second you need the right wheel puller to get the flywheel off. I made one in a lathe(pic 1 & 2), but i believe you can actually buy them.

http://img.photobucket.com/albums/v138/Gutty/puller2.jpg

http://img.photobucket.com/albums/v138/Gutty/Puller.jpg

After you get the flywheel off you'll find your e-start drive gears(pic 3), all very easy to remove, if i need to give you instructions on that stop right now, and take your bike to a mechanic. It's stuff that i no longer need, so figured best just remove it. This is not 100% necessary, really up to you.

Next is to remove the one way clutch from the back of the flywheel(also in pic 3), again, you could leave this in place but it really defeats the purpose......we are trying to remove rotating weight here !! It's easy to remove, just undo the 3 bolts, and give the unit a tap from the front face of the flywheel through one of the holes and it'll fall off. Be sure not to loose the springs and rollers, they will fall out.

http://img.photobucket.com/albums/v138/Gutty/e-startjunk.jpg

Now, get that flywheel up in a 4 jaw chuck on a lathe, true it up as well as possible, and then turn 4mm(absolute maximum) off the diameter either side of the pick up(pics 4 & 5). DO NOT MACHINE THE PICK UP !!!!(the shiney rectangle pad)

http://img.photobucket.com/albums/v138/Gutty/flywheel-light2.jpg

Now if you've done a good job on the turning you may get away without balancing it, but i would advise against it. I made myself a balancing spigot and balnced the flywheel in some wheel balancing rollers. The taper angle of the spigot needs to be approx 5.6 degrees per side. You can see the drill dimples i made to balance it in both pisc 4 & 5.

http://img.photobucket.com/albums/v138/Gutty/flywheel-light.jpg

Now you're pretty much done, give everything a good clean and put it back together.

If anyone around the wollongong/sutho shire area would like to borrow my puller or spigot you're more than welcome, the rattle gun, sadly i had to borrow myself.

I gave it a quick run, seemed to spin up much faster, and that was even with choke on before it was warmed up.
Hope this is some kind of help to some one.....

edit: this is what teh balancing spigot looks like, the flywheel goes onto the tapered part, the rollers allow it to move so you can figure out the heavy side.
http://img.photobucket.com/albums/v138/Gutty/spigot.jpg

[Fiddy Rider]

Thanks for that Gutty, If I do mine I will borrow your tools off ya!! Fill us in on how it goes!! Nick!

[Gutty]

Ok, just took it for a spin, and the difference is like night and day !! Stock wheel is 1kg, i got mine down to around 700gm.......

Seems i may have removed a seal i shouldn't have though......after a lap around the block i had oil pissing out of the flywheel cover. Will have a fix and an update tomorrow.

[eichkay]

Very impressed gutty , I'll probly never get around to doing this as i'll probly be getting a inner rotor kit not too far off in the future ..


But i did enjoy reading it... If i had the bench gear id be outside doing it right now. Im having enuff problems trying to get a tap set of my mate to do a tappet breather on my bike.

[Fiddy Rider]

Yeah gutty ya did I very nice job, can't wait to do it to my pitty!!!

[Gutty]

cheers guys, eichkay, you're on the money mate, the inner rotor is deffinately the best way to go, especially on your donk as you don't have a crank mounted clutch.
If i had the $$ to spare i'd probably go the inner rotor too, but then i have another issue, my crank mounted cast alluminium clutch basket just waiting to explode. Then i'd have to make a billet clutch basket.....and thats a bit of work. I don't imagine this mod will make the engine spin up as far or as fast as an inner rotor so from what i'm told all should be sweet.

Now.....off to fix this oil leak.....i'm thinking that big cog in pic 3 has to go back on, or atleast something in it's place, shouldn't really matter though as it's not directly connected to the flywheel so won't count as rotating mass anyway..... :drunk:

[Fiddy Rider]

Yeah on mine I took the startor motor and everything out and just left the big cog on!!

[Gutty]

well i got my leak sorted, simply put the big e-start cog back on. Now if yoy wanna remove the one way clutch which i do reccomend as it's attached to the flywheel adding weight, all you gotta do is make soem kind of washer, around 3-3.5mm thick with an ID of 19mm, and an OD of around 40mm.

Took it for another ride yesterday, deffinately makes a difference, but unless you got all the tools/machines etc, this really is probably beyond your average back yard mechanic.

[Fiddy Rider]

So does the bike run fine up hills and stuff?? Like is it same as before but just revs harder? So ya just gotta make a washer the same size as the one way clutch?? couldn't ya just leave the clutch on there or is it heavy?? I wanna do it!!!

[Gutty]

Simple way is to just leave the clutch in there......but you just don't loose as much weight that way.
Bike runs fin up hills mate, with my 80kg ass on it, there's not a huge difference, but it does rev a little faster.
When sitting at idle though......it revs up waaaaaay faster, so i'm thinking the lighter you are the better this is gonna work.

[Fiddy Rider]

Ok cool, I am only like 60kg so it should be sweeet!!