Shindaiwa Pole Saw - Tight Chain/Loose Chain

[Bunzena]

Hi - need some advice please.

 

I have a Shindaiwa Pole Saw - which I'm using more than I expected at the moment. It's in good condition - and I try and service it more than specified.

 

Yesterday I encountered a problem. It jammed-up when limbing a tree. Turned-out that the chain had tightened-up so much when running it simply stopped moving.

 

The funny thing is that if I loosen and adjust it - it's very loose on some parts of the rotation and tight as tight on other parts. Tight means really tight - and loose means almost loose enough to jump-our of the groove.

 

So I removed the old chain and replaced it with a brand new one. Same issue.

 

I removed the bar (which is also less than 2-3 hours old) and cleaned it out. The end sprocket rotates beautifully, there are no bends or apparent tight spots and the chain groove is clear and free of any burrs.

 

The oil pump is working and everything seems well lubricated.

 

I then looked at the chain sprocket. It's steel, hefty and looks in good nick. I do have a slight suspicion that it may the culprit - but can't detect any run-out by eye. There's nothing trapped in the teeth of the sprocket - and no discernible damage (it actually looks like 'new'). I took it off and re-seated it - and there was no improvement at all.

 

That just leaves the shaft from the gearbox to the chain sprocket. Again, there's no play in the that - and I can't detect any run-out.

 

Now thoroughly mystified.

 

So my question is this. Anyone got any suggestions as to what it might be? I have seen that there have been some other posts about tight chains on Pole Saws - but that seems to be down to lubrication issues - and in my case it's tight spots and loose spots (if that makes sense!).

 

Could it be that I'm overlooking something?

 

Interestingly this is the only real trouble I've had with Shindaiwa. My perspective is that the stuff they make (made?) is really top-drawer.

[Mitch]

I would also says sprocket

[Rich2484]

First, run the chain drive links in the bar groove with only two or three links in the groove, don't run the whole chain in them. Will narrow any tight spots.

 

Remove drive sprocket and see if it's straight and not bent.

 

Then rotate the drive shaft to see if that's bent.

[DWestbrook]

Sounds like thread stripped on the chain tension adjuster screw.

[easylife]

i run the Shindaiwa 230 with SBA P24 attachment. I have set the oil flow rate to max ie screw fully counter clockwise. when adjusting the screw ensure it is always slightly pressed in. Also ensure that the head gear head nipple is greased regularly and clean debris from guide rails. I have also found when doing conifers that you can encounter blockages behind the plastic guard ie cutting material is not being discharged. I once had a chain made by a local dealer which was tight in the bar they claimed it was the right spec. Purchased equivalent sthil chains with no priobs sorry if iam telling you to suck eggs

[shillo]

ive had the same problem with my shindiawa pruner. a new sprocket solved the problem for me, was expensive though for a genuine one. i would look in to oregon alternative first.

 

My oil pump would randomly stop working causing a tight chain, simply stripping, cleaning and reassembling would not sort it, every time i had to loosen chain right off so it was hanging off the bar, run it for a second or two, tighten chain again. and hey presto oil would flow again, random i know but worked for me. I had two of those heads and both did it occasionally.

[Bunzena]

Thanks to all who've posted so far.

 

Will check-out all the suggestions and report back.

 

I marked one of the chain links on with Tippex (remember that!) and also marked the chain sprocket at the 12 O'clock position.

 

I then rotated the chain and checked to see when it got 'tighter' and 'looser'.

 

The chain 'tightens' and 'loosens' four or five times with one full rotation of the chain (can't remember exactly) - whereas the tighten and loosen 'cycle' repeats with just one rotation of the chain sprocket.

 

That suggests to me that the sprocket or the gear shaft that it sits on may be the problem.

 

Really interesting comments about the setting for the oil pump. It comes 'factory adjusted' (so the manual says) - and that is almost fully screwed down. It does put oil on the chain - but that's a very different proposition from the fully opened-up suggested already.

 

The fact I've tried a new chain - and the bar is relatively 'new' probably rules any damage from lack of oil causing this problem - but it's something I need to think through going forward - so thanks for that.

 

I have greased the gearbox - but I'm wondering if I've been generous enough. There really is no play I can detect in the shaft - despite very vigorous pulling and pushing.

 

(So much to think through!).

 

I'm going to buy a new sprocket - but visually I can't see anything wrong with the current one.

 

I can't see that the adjuster screw is stripped - and the fact that the tight/loosen cycles follow a pattern suggests it may not be this - but I'm going to get the magnifying glass out!

 

Really appreciate all the thoughts - please keep them coming!

[Bunzena]

Okay - problem now officially solved.

 

Shillo - you were right. Fitted a new chain sprocket and the tight/loose spots are now gone.

 

What was really deceiving is that visually the 'old' sprocket looked 'new'. Could not detect any run-out or damage. And the difference between the loose and tight chain was considerable. But something was clearly wrong - so in the bin it goes.

 

Thanks to all who contributed suggestions. (great forum!).

 

Will now go mad with the grease-gun - and probably adjust the oil pump to run a little more generously....