Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

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BigDickMongo
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Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

Hello lads!

A little background:
I bought an SB50 as "primary" transport a little while ago (against my better judgement at the time), I have been lurking, searching, and reading on these forums for a while and would appreciate any / all advice, although I am a bit dum dum (as I mainly enjoy working on old parallel twins aka easy mode) so the whole scoot CVT things is new to me and a bit hard to understand.

The actual issue:
The SB50 can't go uphill at _all_ once warm. When first started/cold it'll struggle it's way up the same incline, but once warm/ridden, it will SLOW right down to walking pace despite revving it's merry little heart out. Even when I first bought it it really didn't go above 25mph, so maybe no clutch engagement and belt is being worn riding around?

The engine sounds and feels healthy. After reading around, It seems like the clutch is toast? Or the belt is? Or the pulley is? This is where I'm lost since I don't understand/work on CVT's and would appreciate pointers to any resources specific to the SB50 that I can be confident in.

I really wouldn't like to spend too much $ on this, I've already bought a new belt (arriving Friday fingers crossed), I just need it to get me to work and back (where I work has CRAP parking and the busses barely run during the summer) and be reliable about it.

I can't figure out where to get clutch parts or _which_ parts to get. I don't have a large & in-charge toolkit/workshop beyond the basic spanners and drill bits so I can't mill stuff or cut springs or anything like that.

What I've done/tried/checked:
Compression is good both cold and warm up, starts are good, engine sounds healthy and revs healthy, there's a new spark plug (but no plug chop)
I've "torn it down" to some degree and cleaned up some stuff but not touched the drivetrain/cvt area since even after watching videos and etc on it I'm not too confident about what I would do

My plan:
Open up the CVT and take a look at it, replace the belt for sure (already bought, no returns :confused: )

I was told that I could scuff up the bell housing in a cross-hatch pattern, and the points at where the clutch engaged with this to increase traction, wouldn't this counter-intuitively remove material from the housing and cause problems in the future?

I am confused with the terminology (and even videos) showing springs and pulleys, what do I _do_ with these to figure out if they're stuck (I have no experience/point of reference) and then what parts do I order in order to remedy the situation?

Again I'd just like to be able to get to work without annoying morning traffic (much)


Thanks to anyone who can help out or point me in the right direction!!!!
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by eclark5483 »

Sure sounds like the clutch or the belt or both. Lucky for you, the SB50 doesn't have a CVT. So the complexities of the transmission aren't as bad as a typical scooter is. Basically what you have is a hopped up spree so fixing it is pretty much the same thing. You can get your clutch repadded for about $50 from JW Parts Plus. On my phone right now got to get my butt into work but I'm sure someone else will post a link for you to contact them
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

Thank you so much for the tips! I'll look up the JW Parts Plus that you mentioned, I think I saw it around somewhere,

What about pullys? I read about them on the forum but got deeply confused as to what can happen to them

Can they get stuck? How do you "unstick" them or tell if they're stuck?

Anyways I'll hopefully begin taking it apart on Friday as it's still my primary transport to and from work, thanks a bunch!
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

Also sorry for the double post, but how do I address possible issues with the clutch like, not "opening" up enough (sticking? is that possible)

I'd like to be prepared when I open it up and start working on it because I do need to use it daily and can't just have it sit around
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by eclark5483 »

Sticking is possible, but not probable. You have springs inside it which prevent it from opening too soon. It works by centrifugal force. The belt spins the clutch very fast, think of a fair ride, like this one:

https://www.youtube.com/watch?v=xfpW_yUgx3k

The spinning is so great, that you are pinned down to the wall when the floor drops. Think of the clutch pads as the people and the bell housing as the wall. What your clutch springs do, is make a resistance to this force up to a certain RPM point, then, when they can't hold it anymore, they engage onto the bell (wall), and your tire starts to rotate. What you are describing happening, seems to indicate that the clutch pads are worn out so they can't get a good grip/bite down on that bell when they are spinning, thus, you rev high, but don't reach much top speed. Also, from your description of it being decent when cold, but not when warm, this says to me the natural heat from the tranny is doing it's thing and making the belt hot and bell hot which also contributes to that loss when warmed up. You have a 30 year old vintage machine, it would seem very likely the pads are worn down if it has been ridden over these years, this is not at all uncommon. It stinks you can't just go to NAPA or the local Honda dealer and grab a new one like you could decades ago, but at least there is at least one company that will repad them for you. They have done 3 of them for me. Nice thick kevlar. They will even bead blast the bell for you for a bit more, or, like some have said, you can just sandpaper this. If the bell is smooth, and the pads are worn down and smooth, the bike's clutch has nothing to bite down on to make the wheels turn, especially at higher RPM. You said you have already purchased a belt, and this is good, but I'll bet anything the pads are junk too. Changing the belt when putting on new/repadded clutch is always a good idea, so if I were you, I wouldn't put the new belt on till the clutch is looked at or repadded. Would help if you could post a picture of the clutch once you open the case side so one of us can advise on the next move. Pretty sure though a re-padding is in your future, but perhaps a good scuff will bring it back to life (for now). Hope that helps.

Edit: In case you haven't found the link to JW Parts Plus, try: http://www.jwpartsplus.com/jw-clutch-worx.html

They don't list the SB50 repad on the site, so you'll probably want to shoot them an E-mail here and inquire: http://www.jwpartsplus.com/contact-us.html

Keep us informed of what they tell you for future reference to others with the SB50, thanks.
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

"Changing the belt when putting on new/repadded clutch is always a good idea, so if I were you, I wouldn't put the new belt on till the clutch is looked at or repadded."

Excellent thank you!
That was a really wonderful description of how the centrifugal clutch works, I understood the basic principles but wasn't sure what "caught" on what on the inside of the scooter,

I'll open it up and take a look and wait to swap out the belt until I can get it re-padded, thank you for the link!
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

So I got it ripped open... half my belt was dust...

I got the front "driven face" (?) part off without an impact gun, but am really struggling with the clutch bell housing, brake won't hold it, can't pin it still with a wrench, any advice or tools I can pick up from local American auto-stores? (Autozone, Orielly and the like?)
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

So almost all good... but reassembling just the cover is getting tricky.

The kicker works fine when the cover isn't bolted on. But the moment I bolt it on it's real hard to kick it and then it gets stuck and doesn't return, and I fear if I try to start it like this it'll f*** something up

Anyone know why this could be happening? is the driven gear too far out or something?
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by Wheelman-111 »

Greetings:

Sounds like the kicker cover assembly is crowding the Drive Face. There are two reasons that come to mind;
1. You omitted the cover gasket, which is factored into the clearances needed for the kicker to engage and then disengage. Make sure you have a thickness of about 0.8mm or the cover fouls the drive face.
2. - And this one can be more serious - The drive face wasn't properly engaged in the crank end splines when you tightened up the nut that holds it on. This generally munches those splines on the crank-end and can end the crank's usefulness. It's surprisingly easy to damage the splines, even with a hand-held wrench or ratchet. The Key is to expand the rear pulleys (takes a gorilla hand) and let the belt slip as far as possible toward center. This frees up a lot of slack at the front. Then CAREFULLY align the front outer Drive Face with the splines and push it all the way to the right (toward the engine block) before threading on the nut.
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

I see ! thank you for your assistance, it seems like it's the second one, how do you suggest expanding those splines? My hand is more chimp than gorilla :(
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by eclark5483 »

Phone a strong friend, bet him $5 he can't squeeze them together. Hopefully you lose.
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by Wheelman-111 »

Greetings:

If you loop the belt around the crank end, then squeeze the upper and lower courses of the belt together it puts enough tension against the spring so that your other hand can pull them apart. Once the belt is wedged in there, it tends to stay put and keep the rear sheaves apart unless you spin the assembly. How bad is the crank munched? Close-up pics if you can.
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

I will try to get pics ASAP, weekends are busy days for me so I'll likely get around to it in a bit
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by BigDickMongo »

So I tried that again and now there aren't anymore starter issues, however, it does have some... clattering? Chatter? At idle. Way way way less than before, but it's still there, is that normal?
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Re: Can't climb / go up even slight hills - Elite SB50 1989(?) - Clutch / belt issues

Post by Wheelman-111 »

Greetings:

It is still not clear that the outer sheave of the Drive Face is fully seated in its correct position. However since the symptom improved, I suspect the cover gasket might for some reason be compressed too much.

Consider this:
1. Loosen the cover bolts a little bit to finger-tight.
2. Start the engine. Then
3. Loosen the cover bolts a turn or so and pull the side cover outward. If the noise goes away, consider reinstalling the cover with some thin shim washers.
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Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
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