Drive chain flailing around like crazy!

[bobber650]

hey there guys,
i have been lookin everywhere for a solution to this problem and have found nothing!

Basically i finally got my 80 xs650 hardtail on the road and got all the bugs worked out but one! when i get to mid - higher range RPMs my drive chain starts flailing and slappin around, hitting my tire and sending a rumble through the entire bike.

now the weird parts is that its top part of chain! the top section that has all the tension! the bottom part that has no tension is fine.

i have adjusted my chain tight and tighter then looser and looser and nothing works, i even tripple checked to make sure my tire is straight.

my bike has the original stock sprockets from 1980 and a new 530 standard chain. im hoping this is a simple fix that someone has already expierenced

i considered getting a chain tensioner however since its the top part of the chain i dont think it would do anything? idk, any help is appreciated!!!

 

[xs650dreamer]

i would replace the sprockets man it might fix the problem

 

[bobber650]

i think ill try that, i have been wanting to upgrade to a 18t front sprocket and a 30t rear sprocket to help with freeway cruising and from what i have read, a smaller rear and larger front will reduce vibrations?

im still open to suggestions before i buy a new set up since money is tight haha

 

[fredintoon]

- - - I finally got my 80 xs650 hardtail on the road and got all the bugs worked out but one! when i get to mid - higher range RPMs my drive chain starts flailing and slappin around, hitting my tire and sending a rumble through the entire bike - - - - my bike has the original stock sprockets from 1980 and a new 530 standard chain. - - -

Hi bobber650,
like the dreamer said, you shoulda got new sprockets.
Old sprockets eat new chain.
Old chain eats new sprockets.
Installed as a set they wear in together like an old married couple.
Once the chain vibes go away and if your 'tail is a stretch you could look
at using a plastic rubbing block like on a dirt bike.
And at installing a Scottoiler or other automatic chain oiling system.
FWIW, I'd sayforget the 18T front sprocket. Yes it can get you a slightly better overdrive
but it will also bring the chain so close to the shifter shaft that it'll wear grooves in it.

 

[bobber650]

so far it sounds unanimous that i need new sprockets, and might as well do another chain with them.

seeing as that is what ill be doing, should i buy everything in 530 chain? or swap to 520 or 525????

 

[xs650dreamer]

bobber i wouldnt go 18t up front get a 17 and a 30 in the rear is the lowest you can go. 18t will take away to much bottom end and yes 30 will help lower your vibrations, message me if you want a new 17t sprock i have a spare from jt

 

[TwoManyXS1Bs]

Sounds like driveline snatch. Wondering about the condition of the clutch hub dampers...

 

[fredintoon]

so far it sounds unanimous that i need new sprockets, and might as well do another chain with them.
seeing as that is what ill be doing, should i buy everything in 530 chain? or swap to 520 or 525????

Hi bobber650
can you even get XS650 sprockets in 525?
Switching to #520 will save you ~ 2 oz. in weight and ~12% in costs but lose you ~25% in chain & sprocket life.
I'd say stick with the #530.

 

[jamesgs4]

before you go throwing parts at it, what is the stretch on your hardtail?

 

[jamesgs4]

also, you can easily run an 18t front without removing the shift shaft guard

 

[fredintoon]

also, you can easily run an 18t front without removing the shift shaft guard - - -

Hi jamesgs4,
there's some onlies that should be in there:-
Only if you run ordinary chain.
Only if you carve the rubber face off the shaft guard.
And
Only if you can put up with telling folks "That's the chain eating it's way through the guard to get at the shifter shaft." when they ask "What's that grinding noise?"

 

[Fndirtygreaser]

I am running a 4.5" stretch. I have monster craftsman chain tensioner. Skate board wheel one. It's a nice heavy duty peice. Stop my chain slapping around. Next I have 18/30 sprocket combo. Love rolling on fwy now. Bottom end isn't the best. But it's bit like I'm stalling due to no torque. Also I have shaft gaurd in place. You can just bend the gaurd a bit. You will see what I'm talking about once have taken it apart.

 

[Screaming Meemie]

I've got no tensioner on mine, but no hardtail either. I'm running 18/30 with the shaft-guard removed and there is no way that the chain will ever hit the shaft and still be on the sprocket.. a solid 3mm gap at the least. Stock chain, size 530. Ive got about 200 miles since the 18t install and i love it, every gear is more usable for how I ride and imo, 1st is not too tall at all. Tightened the chain nice & snug when I put on the sprocket and havent had to adjust it 1mm.

 

[fredintoon]

I've got no tensioner on mine, but no hardtail either. I'm running 18/30 with the shaft-guard removed and there is no way that the chain will ever hit the shaft and still be on the sprocket.. a solid 3mm gap at the least. Stock chain, size 530. - - -

Hi SM,
yes, 18T with a standard weight chain will have ~3mm clearance when the bike is stopped.
At speed the chain lifts off the sprocket so the clearance is reduced but you'll never know it.
Until you fit a heavy duty chain or one of the o-ring or x-ring sealed chains which also use the HD chain's bigger side plates.
Any of those chains on an 18T sprocket has 1mm or less static clearance.
Chain throw when running lifts the chain off the sprocket enough to turn the clearance into an interference and you'll know it by the gnaw marks in the shifter shaft.
BTDT. Here's my progression:-
17T/34T with standard chain.
Switched to 18T front and had to carve the rubber off the shaft guard before the chain would go on..
Switched to o-ring chain and had to remove the shaft guard before the chain would go on.
Removed sidecover to replace clutch cable and noticed the gnaw marks the o-ring chain had made in the shifter shaft.
Switched back to 17T and swapped the 34T rear for a 32T rear to keep ~ the same ratio.

 

[Screaming Meemie]

That may well be true... I only have 200 miles on it. I guess I just assumed a 3mm gap when running, I could fit my pinky finger between the shaft and chain on the curves in the chain and nearly so when the the rivet is adjacent to the shaft. I'll admit that i was considering going to 520 sized hardware... even the awful stretchy stock chain on my Banshee is plenty strong and I think that 'Shee makes more power than my XS. the 530 seems overkill. Anyway, I'll be checking the shaft when I change the oil & check the filters.

 

[jd750ace]

You'll never get it happy without a tensioner on it.

 

[jamesgs4]

Hi jamesgs4,
there's some onlies that should be in there:-
Only if you run ordinary chain.
Only if you carve the rubber face off the shaft guard.
And
Only if you can put up with telling folks "That's the chain eating it's way through the guard to get at the shifter shaft." when they ask "What's that grinding noise?"

I run a 520 o-ring chain, and I didn't carve the rubber off, I just trimmed the mounting tab. It has been that way for years now and works perfectly fine without any extra wear.

 

[bobber650]

Thanks for all the input guys I appreciate it! I'm scrapping the 18t front idea, it sounds like a 17t with a 30t rear should suffice.

My hard tail is the tc bros weld on and I believe it's 0 stretch and 0 lowering. If I remember right my chain is around 113 links? I don't remember exactly tho.

Now this clutch dampner suggestion interests me! Does any one know more about this or how this could be causing my chain slap?

 

[fredintoon]

Thanks for all the input guys I appreciate it! I'm scrapping the 18t front idea, it sounds like a 17t with a 30t rear should suffice.
My hard tail is the tc bros weld on and I believe it's 0 stretch and 0 lowering. If I remember right my chain is around 113 links? I don't remember exactly tho.
Now this clutch dampner suggestion interests me! Does any one know more about this or how this could be causing my chain slap?

Hi bobber650,
as I remember the TC Bros. write-up, their stock XS650 weld-on hardtail does have a 4" stretch.
I doubt 113 links, has to be an even number unless the chain has a cranked link. 112 or 114, perhaps?
Stock XS650 runs 104 links on 17T/34T. 4" stretch with 17T/30T could well use 114 links.
You'll need to do a clutch teardown to check out the damper springs, there has to be a tech tip about that on the site?

 

[bobber650]

Awesome fredintoon! thanks for the info and yes 114 sounds absolutely right, i just remembered it being somewhere in that relm. as for the clutch damper springs, ill have to find that tech article, because once i know what im looking for i would gladly go through the clutch system and refresh it all if there was a possibility of fixing the chain problem. keep the info coming guys! and thanks i appreciate all the help!