Chain slapping jumping under load.
 

Hi,
I have unpleasant behaviour of chain jumping, slapping and making bad noise under load. This is evident on every faster takeoff (more throttle while releasing clutch) and the chain noise lasts only short time, usually while the clutch is in middle position. When I completely release clutch the noise stops. The noise comes from the area of front sprocket.
This behaviour is even more pronounced if I try to take off uphill on a harder terrain, where I need to keep the clutch in middle for a longer time while giving a little more throttle.
Changed front sprocket (JTF259-17), but that had not resolved the problem. Also, new chain fitted and the problem remains. Also, old chain lasted only 5000km! Rear sprocket is still ok condition (46t btw).
I have suspicion for sprockets misalignment. I have done rear sprocket fixture mod, in a similar way as Megadan did. Did not help this problem.

I made a video of the slapping noise! To make this video, and to make the problem audible on the video, I had to simulate harder takeoff: I lifted the bike rear, started the engine, put the bike in first gear, lightly pressed rear brake and started releasing clutch.
https://www.youtube.com/watch?v=sJkZ...ature=youtu.be
On the video is the old chain. New chain did not help.
One more vid, I hope you understand what noise in video I am reffering to.
https://www.youtube.com/watch?v=lYgv...ature=youtu.be

Can someone help me with this?

I would fire whomever fitted the chain, even to my newbie eyes it is way too loose.

Don't have the bandwidth to watch your video but make sure all the engine mount bolts are good and tight.

I'm with Chip on this one, your chain is way too loose. Tighten the chain so you can move it up and down about 1 to 2 cm ( 1/2 inch to 3/4 inch ) then try again.

CT, Paul, as I said, this is old chain (on the video), it is streched a bit, but also it is replaced 2 days ago with new chain, properly tensioned, but problem remains.
Mudflap, all engine mounts are OK.

Kivi... make a video with your new chain on... this video is showing us all this chain slap and we can't tell you what we think with another chain on it...

Be sure to check chain alignment. Someone recently post this same issue.

My rear sprocket "fix" for the Hawks is for taking the excess play out of the rear sprocket more than it is for solving chain alignment.

I would have personally put on a new rear sprocket with the new chain and front sprocket.

OK, to answer several questions. First, here is the video with new chain.
Sound is not very good because i blocked the mic on the phone a little, but I trimmed the video to be short and to contain the problematic noisy, slappy, jumpy chain part.
https://www.youtube.com/watch?v=9hbwt0vmQPQ
Here are some photos of other components:
1pic: sprocket wit retainer removed
2pic: sprocket out side
3pic: sprocket inside
4pic: counter shaft. Looks OK? There is about 1mm of radial play and no axial play on the shaft.
5pic: rear sprocket
I think the rear sprocket is not that worn. There are marks on the sprocket indicating that it was used with worn (prolonged) chain. It is not a problem to replace the rear sprocket if I remove this problem first.

And for the end, the video that explains why I suspect for sprocket missalignment. Let me explain. With the retainer plate removed, when I spin the wheel forward, front sprocket moves to the left for about 2-3mm. When I spin it backward, f. sprocket moves to the right for same distance. I believe, when there is no retainer on front sprocket, the front sprocket "automatically" alligns to the rear sprocket to the ideal position (this may be dependent on chain condition etc).

https://www.youtube.com/watch?v=Fx1MMj1AtJs

I have no tools to check sprocket/chain alignment. This last video pushes me to think about frame/swing arm bendind. I have a suspicion that rear wheel axle (thus also maybe swing arm axle) is not perpendicular to the bike axis. My eyes are maybe fooling me, but I think that, when I look the bike from the rear, and when the bike is level, the rear wheel top is moved a little to the left. Thus, rear sprocket top end also would be tilted to the left, and this maybe is driving the front sprocket to the left.
Maybe the frame bolts for the swingarm are not drilled very precise, thus tilting whole swing arm a little out of bike axis. I know from my own expiriance that the frame on this bike is poorly made, not that much of poor quality material, but poorly in terms on precision. I have a spare swingarm identical to mine, which I might try replacing, to try to straighten the rear axle...

I see what you are saying... the sprocket is traveling back and forth's on the shaft... that's because is is not being held in place... put the retainer back on and torque it down... adjust the chain ... and check for wobble and slap... the noise I am hearing is the chain meeting with the sprocket... or replace it with new sprockets and a new chain...

To add this. F. sprocket retainer plate is also worn. Thus allowing for more f. sprocket play. I ordered new retainer, will be here in 30 days maybe! Anyway, when new retainer arrives, and I install it, it will move f. sprocket to the right (because it will not be worn). I think this would enlarge the problem of sprocket missalignment (if my video and theory behind it is correct (I am talking about f. sprocket moving left right on the shaft)).

Thanks for trying to help, W.S.!
I can do that but I am not sure that will eliminate the force driving the f. sprocket to the left. That force on the video is small, but it is multiplied many, many times when engine is running and on peak HP RPMs. Enough to wear the retainer further to a level that it could be totally worn. Maybe I do not know to adjust the chain properly. Will have to find some tutorial for this.

Hey Kivi... the retainer is worn or even the shaft could be worn... it is only a number of things it could be.... Mine doesn't float like yours on the shaft....

Hello,
I still have the problem!
I have new chain (again), new both sprockets (I put 41 at back - btw waaay nicer combo for my style), 2 new retainers!!!
The problem with slapping at start is even more pronounced (because the first gear is now longer, because of smaller sprocket). It is driving me nuts.

Anyone has an idea what the problem could be?? Today I had a great ride of 140kms, and if I have to start the bike on an uphill it is a NIGHTMARE until it stops slapping and clicking! In second gear also.
The shaft is not worn, shaft is new actually.

Also, did I mention that I worn new chain in less that 2 months, with regular lube and 2-3000km?!?!

I found out that the problem greatly disappears if the chain is adjusted to have just a small slack - 10-15mm while unloaded. But, when set this way, chain streches after every ride! Because chain slack need to be about 6cm unloaded, so that as suspension compresses, at the max compression slack to be 1cm.
So, this looks like a bad design. Badly designed Yamaha cloned frame for this Honda cloned engine. Unfinished product. Poor engineering (if any).
But, I think weather to try to fix this or not. To move the engine mounts, or to move the swing arm shaft location. Also rear suspension need to go to trash and fabricate new.
IF you have any thoughts......tomorrow I will put a photo with sprocket cover removed.