New chain & Sprockets

[DazB]

I got up early this morning and headed out to the garage to try and pinpoint the problem.

As I've already said, I marked and noticed the tight spot was always on the same part of the front sprocket. So i marked it again and took it off the spindle turning it 180 and back on again. My thinking is, if its the shaft the tight spot should be on the other side of the sprocket, opposite the mark i made, but no, it was still in the place i marked! To me, this means the sprocket is at fault as the tight spot is alway on the mark i put on the front sprocket.

I took it off again and put the old sprocket on and the tight spot had gone. Im confident the Renthal front sprocket is off. I going to get a new one and see.

Can someone recommend a good quality front sprocket. I have always used Renthal but I don't know if i should just get another one!?

ta

[sirch345]

I'm glad to hear you may have found the problem, ten out of ten for your persistence

I must admit a faulty front Renthal sprocket is not something I can recollect. May be it's possible a faulty one slipped through by mistake. You could phone your supplier and ask if anyone else has had the same problem, it could be a faulty batch,

Chris.

[popkat]

JT or Afam sprockets are both good quality


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[DazB]

I'm glad to hear you may have found the problem, ten out of ten for your persistence

I must admit a faulty front Renthal sprocket is not something I can recollect. May be it's possible a faulty one slipped through by mistake. You could phone your supplier and ask if anyone else has had the same problem, it could be a faulty batch,

Chris.

Me nether Chris, I’ve always used Renthal with no problems. Good idea about ringing the supplier, I’ll do this tomorrow.

Thanks popcat, i look out for them.

I hope it is just a new sprocket, I’ve been second guessing myself all day!


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[Wicky]

Can you determine if the sproket is warped by measurement or laying it on a flat surface?

[DazB]

Can you determine if the sproket is warped by measurement or laying it on a flat surface?

I did measured the diameter at 90 degrees and it was out by 0.2mm, but my digital vernier calipers are not great. I’ve not checked how flat it is, I’ll have I look, thanks.


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[sirch345]

I also was trying to think of a way in which you could check the front sprocket for it being out. My way of thinking from what you are experiencing must mean the teeth (or at least one of them) are not evenly spaced. So with that theory in mind, you could try wrapping the chain around the front sprocket (with the sprocket removed from the main shaft will make that easier) as far as it will go, until it touches itself. Then see if it's possible to detect the chain being raised away from the sprocket centre where your mark is, as in it's not sitting down so low as the rest of the chain. Only an idea,

Chris.

[DazB]

I also was trying to think of a way in which you could check the front sprocket for it being out. My way of thinking from what you are experiencing must mean the teeth (or at least one of them) are not evenly spaced. So with that theory in mind, you could try wrapping the chain around the front sprocket (with the sprocket removed from the main shaft will make that easier) as far as it will go, until it touches itself. Then see if it's possible to detect the chain being raised away from the sprocket centre where your mark is, as in it's not sitting down so low as the rest of the chain. Only an idea,

Chris.

Yeah I could see that working, I’ll give it a go when I’m back in the garage on Wednesday. However if it’s the centre of the sprocket that’s out, this wouldn’t affect the teeth, ie the teeth would be ok and chain fit ok.

I don’t think I have the tools to measure the sprocket to any satisfying degree, I’m going to get a new one and hope it’s ok!


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[tony.mon]

From memory, doesn't the output shaft have a small hole or dimple in the end?
If so, you can measure from that point to the base of the lowest point between each tooth.

[sirch345]

I also was trying to think of a way in which you could check the front sprocket for it being out. My way of thinking from what you are experiencing must mean the teeth (or at least one of them) are not evenly spaced. So with that theory in mind, you could try wrapping the chain around the front sprocket (with the sprocket removed from the main shaft will make that easier) as far as it will go, until it touches itself. Then see if it's possible to detect the chain being raised away from the sprocket centre where your mark is, as in it's not sitting down so low as the rest of the chain. Only an idea,

Chris.

Yeah I could see that working, I’ll give it a go when I’m back in the garage on Wednesday. However if it’s the centre of the sprocket that’s out, this wouldn’t affect the teeth, ie the teeth would be ok and chain fit ok.

I don’t think I have the tools to measure the sprocket to any satisfying degree, I’m going to get a new one and hope it’s ok!


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That is true, does that mean when the chain hits your marker point on the front sprocket the chain tightens up at that point

Good luck with it on Wednesday,

Chris.

[E.Marquez]

Take all the bolts around the edge of the cover, 6 IIRC but they are all different lenghs so devise a way off keeping the patern thay came out, bit of card with holes works. Do not put them on the floor & then kick them as you get up to do something...

Just a tip in general, but it is also applicable to the cover in question...

Mother Honda has a spec on how many threads on an M6 fastenr need to be screwd into the case after passing though the part being assembled... and it is a constant.. You cna take all those fatsner from the chain cover and slave, put them in any random hole (on the motor you nasty minded bunch) and you will see the ones that stick out too far or are not long enough....move a few around to different holes (yes, in the motor case) and you will find once right they will all stick out from the cover the same amount.
This works on literally all motor bolts of the M6 size.

The cardboard trick might be faster overall but the point is, its really easy to fix if you mix them up.

[sirch345]

Just a tip in general, but it is also applicable to the cover in question...

Mother Honda has a spec on how many threads on an M6 fastenr need to be screwd into the case after passing though the part being assembled... and it is a constant.. You cna take all those fatsner from the chain cover and slave, put them in any random hole (on the motor you nasty minded bunch) and you will see the ones that stick out too far or are not long enough....move a few around to different holes (yes, in the motor case) and you will find once right they will all stick out from the cover the same amount.
This works on literally all motor bolts of the M6 size.

The cardboard trick might be faster overall but the point is, its really easy to fix if you mix them up.

That is handy to know, cheers Erik

Daz, if you think the front sprocket is oscillating as it turns, replacing one of the front sprocket cover bolts you can wrap a short length of stiff wire around the bolt and use it as a pointer at the tip of the sprocket teeth. Turning the sprocket by hand (chain removed will probably be best, or you may be able to do it still fitted) you should be able to detect if it's definitely out. If it is oscillating you will need the pointer set at the highest tooth,

Chris.

[DazB]

I re-measured the sprocket again last night and I could not find anything wrong with it. I’m buying another make sprocket tomorrow, if the issue is still there with the new one then I’ll need to rethink. Though I’ve been over thinking this all weekend!


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[sirch345]

Fingers crossed the new sprocket does the trick,

Chris.

[tony.mon]

Yes, cause if it isn't the sprocket you have a buggered bearing on the output shaft, and that's a split-the-crankcases job....