50V godawful racket...

got the moby running and riding...

'78 50V a

all stock except for 14mm clone sha...

when i start it up the vario makes a godawful noise...is the grease gun trick to the vario and pedal crank all it needs?

i guess i could tear it all down but would prefer not to.

also, the engine vibrates like crazy (normal for these bikes?)...i know i should replace the bushings but it sounds like a pita...

have no grease gun but can probably borrow one...

thanks!

Re: 50V godawful racket...

oh man, gonna have to strain the memory on this one. I had a similar problem with my variator and I think I figured out a bushing was missing and so one of the parts was just kinda flopping around on the crank shaft. Not sure if that's your problem or not but I'm not too optimistic that a grease job will do much. The engines shouldn't shake too bad with good motor mounts but when the motor mounts do go it will shake pretty bad. Replacing them isn't bad if you have the tool. Treats sells one now or you make your own like I did. Spend the extra money any by the good motor mounts, I hear the cheap ones don't last at all.

Re: 50V godawful racket...

thx for the info...

I'm gonna try the grease and if things don't settle down i guess i can crack the vario open and see what's what.

i was thinking about getting the napa bushings and giving them a shot...then again maybe i should just buy the nice ones from treats...any feed back on how well the napa ones work?

Re: 50V godawful racket...

I attached the part I was missing out of mine that was causing the racket. Doesn't require too much disassembly of the variator but I do recommend buying the puller tool and something to stop your piston. (like this and this)

I'm unfamiliar with the napa bushing your referring too but the nicer mounts treats sells aren't that pricey (see) but know what size motor mount bolt your engine takes. They came out with a larger and smaller diameter one. Those mounts take the smaller diameter bolt so if your engine takes the larger one your going to want to make yourself some sort of sleeve. (edited)

Variator.JPG

Re: 50V godawful racket...

thx much...i usually use the rope trick for a piston stop...mine is a purely stock bike (except the carb) and the napa bushing will require some work but only cost 3 bucks a pair...

i figure i'll not tighten the motormount bolt too much which seems to be why a lot of these retrofits fail...

really appreciate the help

thx!

Re: 50V godawful racket...

***Kim Jong illest*** /

could be your starting clutch getting stuck. pretty common

Re: 50V godawful racket...

so how hard is it to disassemble everything? i'm assuming i have to get the puller...anything else?

Re: 50V godawful racket...

Depends on how 'apart' you want to get it. this will come in handy if you really want to get the whole thing apart. There are a few circlips in there too so some circlip plyers are nice too.

edit:

Also I want to say there is an oversized hex nut you have to get off. You might have to get a large socket or something for that. I think that's what I did. (edited)

Re: 50V godawful racket...

ha! yeah...i've pulled my pug vario apart numerous times...

as far as buying all the specialty tools that's nice and all but i usually improvise...for my pug's locknut i do multiple wraps with a strap around the vario using a 2x4 and air wrench...

Re: 50V godawful racket...

yeah, I don't have that specialty tool either, I just lined some bolts up in a vice.

Re: 50V godawful racket...

thx man...this should be fun!

Re: 50V godawful racket...

update...so i don't think it's the vario anymore...i ordered the jd mounts and will install next week...

pulled the clutch apart and sanded some rusty spots and the pads...didn't help...started her up and listened really close...it sure appears as though the sound is coming from the flywheel...

anyone ever heard of such a thing?

i know i'm gonna have to pull it to check but what would cause the flywheel to make such a racket?

Re: 50V godawful racket...

Michael Koerber /

most likely the counterspring hits the bolt/arm of the driven pulley. Loosen the two bolts, which fixate the bracket and spring. Readjust your spring. Happened to me a couple of times after a rebuilt.

Re: 50V godawful racket...

thx! i haven't checked that out but will adjust when i install the new engine mounts...i have the lower engine bushing coming too...

tried to get the novi nut off...just about busted a nut trying to...i know, i know righty loosey...used the pipe clamp method and 3/8 in drive with a breaker bar and still nothing...

anyway, i'm gonna ask my buddy if he can use his air wrench on it...that thing is on there tight!

Re: 50V godawful racket...

My engine made a lot of noise which I thought was the vario, but it was just old crank bearings.

Re: 50V godawful racket...

yeah, i thought about that too...not ready to go to a full tear down just yet...it actually runs really nice...just noisy as hell...

Re: 50V godawful racket...

so i got the novi nut off! here's my setup...10 bux for a chain wrench at harbor freight, 12 in breaker bar and a block of oak...it was actually easy!

btw, the chain wrench will fit on most any flywheel/vario you have on a ped...

Re: 50V godawful racket...

Kiel the Canuck /

I went with a rubber strap wrench to avoid scuffing the flywheel.

The novi nut on mine was in very poor condition, and it was toast by the time I got it removed. You can replace the nut with a new hex nut here:

https://www.treatland.tv/ProductDetails.asp?ProductCode=mbk-flywheel-REVERSE-nut-11x1

Now then, onto the noise...

It can be the crank bearings themselves, or it could be a combination of noises in the variator assembly.

There's a needle bearing assembly, bushings, and flatwashers all stuffed in the space between the variator and the crankshaft. If there's any missing shims or spacers it could be rattling there, or problems with the needle bearing.

If it rattles when it's NOT running (just turning the variator over), you may have a loose starter clutch arm.

Re: 50V godawful racket...

thx! the chain wrench doesn't scuff the flywheel at all...a strap wrench wasn't cutting it for me...kept slipping...

anyway, i've dropped the engine, replaced the engine mounts with the jd ones from treats, managed to get the vario off completely, i have a huge airleak on the cases so i'm replacing the crank bearings/seals, small end bearing, and vario bearings...

this moby stuff is different but kinda fun just the same...

after all this work is done i'm hoping that should just about cover everything...maybe...lol

Re: 50V godawful racket...

Kiel the Canuck /

matt madden Wrote:

-------------------------------------------------------

> thx! the chain wrench doesn't scuff the flywheel

> at all...a strap wrench wasn't cutting it for

> me...kept slipping...

>

> anyway, i've dropped the engine, replaced the

> engine mounts with the jd ones from treats,

> managed to get the vario off completely, i have a

> huge airleak on the cases so i'm replacing the

> crank bearings/seals, small end bearing, and vario

> bearings...

>

> this moby stuff is different but kinda fun just

> the same...

>

> after all this work is done i'm hoping that should

> just about cover everything...maybe...lol

Cool. My first rebuild was on my Moby, and I learned quite a bit. Important things to note when you're doing the bottom end: Heat is your friend. The bearings are held in the cases and on the crank with interference fit. Gently heating the cases surrounding the bearing can (with luck) allow your case to split without even thinking about using a hammer and risking crank issues.

Removing the bearings is (without using the special moby tool) best accomplished with a bearing splitter.

Temperature differential is the key to assembly. Freeze the crank, heat the bearings in an oven - if you do it right, they'll slide right on. Keep a pipe handy just in case they start to shrink too fast and need one last bit of help getting on. Any tapping down should be done with the crank supported by a steel plate in between the counterweights.

Oil up your case casket ahead of time, give the crank lots of time to settle to room temperature (I'm paranoid, so I give it at least a couple hours), then throw the whole thing into a ziploc bag and into the freezer.

Then you kind of do the same thing with heating the cases with the new gasket and seals.

Re: 50V godawful racket...

hey thx...

i've done this with a pug case and it was a bear...

did the bearings on the crank first then the crank/bearings into the heated case...

one question tho'...seals look like they get fitted into the cases first...are they metal lined or something...tomohawk tuning taps them in...springs facing in or out?

thx again for the tips...

Re: 50V godawful racket...

Kiel the Canuck /

matt madden Wrote:

-------------------------------------------------------

> hey thx...

> i've done this with a pug case and it was a

> bear...

> did the bearings on the crank first then the

> crank/bearings into the heated case...

> one question tho'...seals look like they get

> fitted into the cases first...are they metal lined

> or something...tomohawk tuning taps them

> in...springs facing in or out?

> thx again for the tips...

Original style seals are metal on the outside with a rubber lip held by spring. I went with modern style seals that fit the holes, but use rubber coated metal outers. Easier to install and make a better seal. The crank seals are there to prevent air from getting IN, so the "lips" on the seal face outwards, so when the case is under vacuum the seals pull shut.

The rubber-coated seals are available from all sorts of industrial supply shops. I bought mine from a place that services/repairs hydraulics.

Thread from last year with a step-by-step rebuild guide and videos: https://www.mopedarmy.com/forums/read.php?6,3476614

Guide to SPI crank seal installation by the expert, Rebel Moby:

http://mabecanemobylette.freeforums.org/installing-spi-seals-t1429.html

(The rest of that forum is an excellent resource too)

Thread discussing the seals and where to get them:

https://www.mopedarmy.com/forums/read.php?6,1856185,1856426

Rebel Moby isn't around here much anymore, but I'll do what I can to help spread the gospel :D

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