Spun, how do you fix?

♣Slew Foot♣ /

so i get the sachs 505 1a upto 33 mph

with just minor pipe and airbox adjustments and after a long ride i see the flywheel is begining to back off. when i got it it was pretty worn (the threads). after taking the flywheel off i see the threads are toast, i retap it several times and got a locknut it still spun off, WTF do i have to weld it on there or what. any ideas i really do not want to splay the whole engine and put out $ on a new crank, when it has been running better than ever.

Re: Spun, how do you fix?

Grey Kingsley /

well if the threads wore off and then you re-threaded it, wouldn't it be too small to hold the flywheel anymore?

I don't know, I'm no fucking machinist!

Make sure you clean the threads real good. People will say clean them with brake cleaner or carb cleaner or whatever. I use some 90% rubbing alcohol.

Then, if backing off is really such a problem, use some red loctite. Torque the nut on to like 30 Lbs(I think, might be more or less). Red loctite should prevent it from coming off.

Re: Spun, how do you fix?

♣Slew Foot♣ /

i think they are totally shot. it takes like 11lbs and starts spinin i am thinking sand smooth rethread to a smaller dia thread or slam it on as best and tight as i can, cut a slot across and weld4eva.

i think i can disassemble the engine if i ever need to remove the crank, grind it off and split the nut if i can't. anything but rip apart a perfectly working engine.

Re: Spun, how do you fix?

Grey Kingsley /

You don't want to weld it on permanently because then you wont be able to replace anything on the stator(points, coils and condenser)

Re: Spun, how do you fix?

♣Slew Foot♣ /

sachs splits top and bottom. i can theoreticly disassemble the engine without removing it.

it has good coils, new points, new condensor.

like i was sayin, i am thinking about it, i mean to really do it right. i would have to tear down the whole engine and if thats the case. why not just go for the D crank, i mean the stator and flywheel is cheaper than a crank.

i have a few stators and flywheels lying around but no cranks, i do not think i am as crazy as i sound.

i'll do it i swear i will, don't push me man, back off.....

Re: Spun, how do you fix?

Probably Fred /

Install flywheel tap it on a little even, tighten nut best you can ,

Put 2 little tack welds on nut/crank end.

If you got to break welds later on oh well

Re: Spun, how do you fix?

♣Slew Foot♣ /

yeah thats what i was thinking,

i talked to the truimph mechanic, he sugested to take the entire flywheel off coat the taper and housing along with the crank with loctite, install then heat with an heat gun and it will setup and wick better.

i tried it, i took all the washers off, ran a brand new 10m 1.25 tapped the fly wheel with a mallet real snug then got the nut to about 20lbs

took the hair dryer to it for ten minutes.

Time will tell. then its weldinng time.

Re: Spun, how do you fix?

♣Slew Foot♣ /

well that worked well, for an hour or so.

last chance is on payday when the shithead at autozone can have the stupid deposit on the thread kit.

it kinda pisses me off when these minimum wage lackeys can not loan you just one stupid die for 15 minutes with your bank card and DL as collateral. even though the garage i work for part time has a corporate account with them. its like some power trip.

well back to the topic, i am gonna try taking it to 7/16 standard. but seeing as the original threads are turned while the crank is still hot to temper them, it will last maybe a week.

so the prepping begins. first, i am servicing the points making sure they are tip top. rerunning the condensor to the outside and am thinking of replacing the coils with two tomos 12v coils i have lying around.

if i have to tack weld it, i want to make sure i can maintain it the best i can and may as well upgrade while i am in there.

any thoughts or sugestions before its too late?

Re: Spun, how do you fix?

use a 3/8`s or 7/16`s die make new threads

Re: Spun, how do you fix?

Run a die over it to go undersize and use a new nut and a wave washer. You could also make anchor holes in flywheel and nut and use lockwire and she will never spin off unless you cut the wire first. 1977mopeds sells wire pliers and lockwire

Re: Spun, how do you fix?

♣Slew Foot♣ /

i was thinking of the hole thing but it is recessed too far to get in there and then drilling the crank while on the bike is hairy at best or lining up the holes in the crank and nut that were not made at the same time. daunting.

i will try and retap first, then its weld time.

Re: Spun, how do you fix?

If you're going to go the lockwire route, wouldn't it be better to drill holes in the nut and crankshaft, rather than the flywheel? Seems to me that the nut and flywheel could spin together and loosen.

They really should have used left-hand threads on those things.

Re: Spun, how do you fix?

♣Slew Foot♣ /

well. i got the autozone guy to reconsider. i left a ten dollar cash deposit on the lone die. the manager walked in on the transaction and started to bitch. i was tellin him the cost of the whole kit is 90.00, i just wanted to borrow the lone die out of the set of like twenty.

I reminded him that the garage i part time at is one of his clients, and the three clerks there know me. i even bought the nuts there, overpriced as hell too. just to take some heat off the clerk.

it looks good really, it might just hold. i took the fly wheel back off and ran the thread all the way to the taper hardcore, 3/8ths.i re ran the die three times, making the threads a little deeper each time. i put the hi temp thread lock all over. ran it ten minutes, shut it off, just to heat it all up and test the new nut.

looks good but i think i should get a new woodruff key. mine seems to be rounding off at the top from the mishaps, damn freaky size. they are nazi's. payday, i will scower the far reaches of the deepest interweb to find a new one. treats and junkyard are a no go, out of stock.

it would have been way to easy to have a standard metric or other key, i could just get at the local hardware store for 33 cents.

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