Chain Slack Advice - After Sprocket Change

[chunkygoat]

Hey hows it goin brothers and sisters....I have a menial question regarding my chain slack after replacing the chain and both front and rear sprockets. I'll try to give as much background on the situation as possible to give you the context of my dilemma.

So in the beginning of April I changed my front sprocket, rear sprocket, and chain. All replaced with stock parts from bike bandit. 15t up front, 48 rear (if I recall correctly), with the 530 stock chain. I met a mechanic that worked at my local Yamaha dealer for 20 years and he left them to start his own garage. While talking to him, I learned a lot of shiesty moves Yamaha makes at the dealer - so I've been into doing own wrenching for the past year.

Well I personally replaced the above mentioned parts. I reassembled everything and positioned the rear tire, while on the center-stand, back far enough to give the chain tension to make it taught, but not super tight. I rode it for about a week, and as expected, the chain was slightly loose - so I loosened the rear axle nut, and slid the tire back about 3 notches (the notches on the swing arm) and the position was perfect on both sides.

Now, about 3 months and 3,000 miles later - I felt my chain slip then grab my sprocket while engine braking fairly hard. So I assume my chain just needed to be tightened again. I slid the tire back as much as I needed to again to get the chain taught. Well now there's only 2 notches left before the rear tire is as far back as it can go.

Also - there were "sparkles" when you look closely scattered around the rear wheel rim, swing arm, and up near the front sprocket - indicating to me that metal shavings were being scraped (most likely) from the front sprocket - because the rear sprocket looks tip top.

So my question lies here. Having the bike on the center stand- when adjusting the position of the rear tire (forwards or backwards) - with the rear wheel in the air - the chain is supposed to be slightly looser than you would want it when there is weight baring down on it -- correct?

Is there a general rule of thumb when adjusting your chain slack? If so - what is that rule of thumb? I've been having these chain slack issues and I doubt that it is a catastrophic impairment....but I don't want to destroy my brand new sprockets or chain. So if there is something I missed, or something I am doing wrong - I'd like to know.

As of now, the chain is fine, and only time in the saddle will give me results (good or bad).

So how tight is the chain generally supposed to be when the rear wheel is lifted? Should I be drastically concerned about the few metal specks I found? Should I cut a link off the chain, and slide the tire forward again if I continue to slide the rear wheel back to compensate for the loose chain? Should I buy a new chain? What do you guys think?

Like I said - as of now everything is golden - just want to know if I could be doing something BETTER (or if I am doing something wrong).

BTW I don't ride hard and I RARELY if ever do wheelies anymore - so I doubt my riding style would attribute the chain loosening so drastically.

Thanks again for any advice on this guys.

-Matt

 

[yamihoe]

I usually like to see no more then 3/4 inch of up/down slack in the chain with the bike sitting on the ground with some weight on it.

as to the metal flakes....

 

[CNY Fizzer]

It sounds to me as if you have over tightened the chain. I don't have the manual here but if I remember correctly there should be almost 2" in total chain travel (pushed down - to pushed up) when on the center stand. I'm sure someone will write in and give you the proper measurement. I hope you have not over stressed your chain but that an unusal amount of stretch even for a new chain.

 

[iSteve]

I also think you chain is way to tight and when you thought the chain was skipping on the sprocket you actually were locking up the back wheel and skidding the tire.

 

[Motogiro]

Your chain slack should be about 1-3/4"to 2-1/8" travel. Chains do stretch when they are overtightened. Always set chain to manufacturer's specs.

I have my chain stretcher right next to my 2x4 stretcher and piston stretcher.

You'll notice the specs. for new chains are never other that the OEM spec.

See attached:

 

[PhotoAl]

I would be very concerned if the chain has stretched that much. I have adjusted mine a couple of times over 6,000 miles. The first time was not long after I put it on and the second several thousand after and not that much.

Check you slack like the other have said, it is easy to miss a point like not having it on the center stand etc.

1. How many links does your chain have? Don't remember the stock length (118 i think but CHECK) but some of the kits may have 120. Bought my stuff from SprocketCenter and they sent me the correct length - also checked it against the stock chain after I took the original off and before putting the new one on - the old one was not much longer.

2. Is it a real DID? If your chain is stretching that much then it is too much or I am not understanding what you are saying. Do the tests like how much can you pull the chain away from the sprocket on the rear sprocket - in the center of the section that is wrapped around the sprocket.