What's on your bench today?

[spudulike]

It is the saw of the son of a guy in the next village, think it is just a firewood saw - new part on order:thumbup:

[C.J]

new part on order

 

Rim sprocket kits are available:001_smile:

[mikerecike]

Its the tiny tach 20K workshop model that the battery can be changed on! No problems so far and very useful!

 

OK spud/anybody it's late just got in first wrestle with my new tiny tach20k - sure this is a dumb question - but settings for 4 cycle = 360?720?

2 cycle 360?

 

thanks

[GardenKit]

Use 360. Thats for 1 pulse per revolution. This applies to most small engines that you will encounter in this trade, both 2t and 4t.

 

You will soon know if its wrong, as you should get to be a good judge of speed range without using the tach, so if for example you were expecting 12k - 14k, but only got 6-7, then you would know it was set wrongly.

[Ty Unnos]

I want to get a tach so I can start tuning up my saws.

 

Anyone used one of these:

 

Stihl,Husqvarna chainsaw digital tachometer/hour meter.Genuine Andy Tach tool!!! | eBay

 

Or is there a better option?

[spudulike]

I want to get a tach so I can start tuning up my saws.

 

Anyone used one of these:

 

Stihl,Husqvarna chainsaw digital tachometer/hour meter.Genuine Andy Tach tool!!! | eBay

 

Or is there a better option?

 

The tach needs a refresh of 0.5 second and go up to 20K revs, slower than this and it will drive you mad. The ones that have built in antennas are easier to use and the question on settings earlier 360 deg as the engine fires on each stroke and is singlew cylinder!

[mikerecike]

Use 360. Thats for 1 pulse per revolution. This applies to most small engines that you will encounter in this trade, both 2t and 4t.

 

You will soon know if its wrong, as you should get to be a good judge of speed range without using the tach, so if for example you were expecting 12k - 14k, but only got 6-7, then you would know it was set wrongly.

 

Thanks Gardenkit

That opens up an interesting discipline - sensing what the rpms are- thanks - but I just don't understand how the 360 setting works with 4 strokes - i thought there was 1 fire for every 720 degrees rotation - each stroke being 180deg?

 

Cheers

[GardenKit]

Thanks Gardenkit

That opens up an interesting discipline - sensing what the rpms are- thanks - but I just don't understand how the 360 setting works with 4 strokes - i thought there was 1 fire for every 720 degrees rotation - each stroke being 180deg?

 

Cheers

Think of it like this.(single, or twin small 4t engines)

The flywheel rotates once per engine rev.

The magnets pass the ignition module (coil) once per rev)

Therefore creating impulse once per rev, therefore sparks every rev.

One spark occurs on the power stroke, and is used.

The other spark occurs on the exhaust stroke and is 'wasted'

 

One impulse per rev will count RPM

[GardenKit]

This is one reason to check, and grease your clutch drum needle bearing.

 

This saw was not oiling, the cause was obvious, this pump just was not going to work anymore.

 

This was caused by wear in the needle bearing AND the centre bore of the drum.

 

The wear allows the drums edge to drop, this applies pressure to the worm drive arm which then grinds away at the oil pump, in this case weakening it sufficiently to break up.

 

[spudulike]

Never ceases to amaze me what abuse needle bearings will take and still work!