What's on your bench today?

[Blackbriarwoods]

660 back on the bench, been using it today and I love the thing (when first collected I wasn't certain it was any good but got it cheap and spent money doing it up with genuine bits). Only on the bench to make sure everything is still tight, where it should be and nothing is catching.

[spudulike]

Then make sure you don't drill straight through as you may end up in the oil tank. It will be worth checking what is behind that hole if you do go too far. 

I guess I may be thinking of the 660.

You may need to get a bottoming tap if your tap is a bit tapered as it will cope with the blind hole better and be aware that helicoils get longer on fitting.

[Muddy42]

12 hours ago, spudulike said:

Then make sure you don't drill straight through as you may end up in the oil tank. It will be worth checking what is behind that hole if you do go too far. 

I guess I may be thinking of the 660.

You may need to get a bottoming tap if your tap is a bit tapered as it will cope with the blind hole better and be aware that helicoils get longer on fitting.

 

Thanks.  I'm taking a bit of time over this. I've got the handle and pull cord mechanism off the saw and clamped it to a board under the drill press.  I've been testing for level and square with a smaller 4mm drill bit before I actually cut metal.  l'll use tape as a depth stop.  I have a broken tapered tap that I'll try and make into a straight tap. fingers crossed.

[Dan Maynard]

5 hours ago, Muddy42 said:

 

  I have a broken tapered tap that I'll try and make into a straight tap. fingers crossed.

Are you just going up a screw size or going for the helicoil? Helicoil tap is approx diameter of an M6 but pitch of M5 so bit of a special.

[Muddy42]

3 minutes ago, Dan Maynard said:

Are you just going up a screw size or going for the helicoil? Helicoil tap is approx diameter of an M6 but pitch of M5 so bit of a special.

Helicoil first.  I've ordered an M5 kit which I know comes with a 5.2mm drill bit (presumably to allow for the width of the helicoil) and a tap.  The tap looks slightly tapered but I'd do some measuring beforehand.  Hmnn different pitch, I'll have to check that too. 

[Muddy42]

On 06/09/2023 at 14:55, Muddy42 said:

Helicoil first.  I've ordered an M5 kit which I know comes with a 5.2mm drill bit (presumably to allow for the width of the helicoil) and a tap.  The tap looks slightly tapered but I'd do some measuring beforehand.  Hmnn different pitch, I'll have to check that too. 

 

The Helicoil seems to have worked in the blind hole. I'm one tank of fuel in and it hasn't vibrated off yet.

 

I started off with the 5.2mm drill and 5.2mm tapered tap that came with the kit.  I was very careful to not go too deep with either.  I cleaned out the hole with a cotton bud and carb cleaner.  I then made a very heath Robinson straight tap from a 5mm bolt with a slit down the middle to remove the swarf. I then levered the slit out to try and get it to 5.2mm.  I'm not sure it was a perfect fit but it did remove some more aluminum from the base of the hole.  Finally I removed two coils from the Helicoil and ground the bolt to get a good fit, knowing the assembly tab wasn't going to be removed, fitted with locktite and good to go. I'll try and never remove it.

 

[Mik the Miller]

My old 660 died that week, wouldn't start, seemed to be low in compression.

To be fair it's not been right for a while and I should have looked at it earlier (rather then just when I needed it...).

 

I took the exhaust off and it looks like the rings have given way.

The piston and bore is well scored, past repair.

 

What should I buy ?

Is there any advantage in getting one of these 'big bore' kits ?

The Hyway for example

Or a standard 54mm set from Meteor ?

 

The lower cost Nikasil/unbranded versions ?

 

 

[maybelateron]

I would just sell it for spares/repairs and get a new 661. That's what I did when my previous one died. And run it on Aspen from the start.

[spudulike]

1 hour ago, Mik the Miller said:

My old 660 died that week, wouldn't start, seemed to be low in compression.

To be fair it's not been right for a while and I should have looked at it earlier (rather then just when I needed it...).

 

I took the exhaust off and it looks like the rings have given way.

The piston and bore is well scored, past repair.

 

What should I buy ?

Is there any advantage in getting one of these 'big bore' kits ?

The Hyway for example

Or a standard 54mm set from Meteor ?

 

The lower cost Nikasil/unbranded versions ?

 

 

Get a photo up of the piston and bore to give us an idea of what has failed. Hyway do make decent kits, their big bore may be difficult to get a good seal on the gasket, that is what I have found the one time I used one. Meteor and Hyway kits are fine and I have a strong hunch that Hyway make the cylinders for Meteor anyway.

Forget the cheap kits, they are cheap for a reason....the plating is like cheese, soft cheese and the piston to bore clearance is poor at best.

Before spending out, make sure the big end is in good shape. 

The 660 is a rock solid saw and worth repairing if you have a bit of know how.

[Mik the Miller]

I've bought the Hyway, new gaskets and a gudgeon bearing.

I agree, for £35 for a piston/ring/cylinder set, how good is it ?

 

Here's the photo's.

It looks like the rings gave way and chewed everything up, no idea why, it's all OEM.

I think its a 2007 so I guess thats not bad, doesn't have a hard life, my 880 gets used a lot more and I tend to use it with a smallish blade (20")

 

 

Needs a bit of polish that ....