What's on your bench today?

[NI Tree]

fond a 245r in a scrap bin complete so have orderd a piston and crank seals so just got to clean the cylinder there is a first time for every thing

[spudulike]

That cylinder looks fine, the lower extension of the barrel is just to support the piston and as long as it is smoothed out with a diamond file and 400 grit paper will be fine.

 

The other damage is to the lower transfer port, no timing is achieved through this and it can be again smoothed. The transfer just takes the fuel air vapour from the lower crankcase void in to the cylinder head.

 

The critical areas are the upper transfers, upper exhaust and lower inlet as well as the bore surface above the exhaust port - if this is the only damage, get a decent piston, rework the damage and reuse the cylinder!

 

Inspect the thing carefully and if no other damage is present, all is good and a lesson learnt!

[lakeyboy]

That cylinder looks fine, the lower extension of the barrel is just to support the piston and as long as it is smoothed out with a diamond file and 400 grit paper will be fine.

 

The other damage is to the lower transfer port, no timing is achieved through this and it can be again smoothed. The transfer just takes the fuel air vapour from the lower crankcase void in to the cylinder head.

 

The critical areas are the upper transfers, upper exhaust and lower inlet as well as the bore surface above the exhaust port - if this is the only damage, get a decent piston, rework the damage and reuse the cylinder!

 

Inspect the thing carefully and if no other damage is present, all is good and a lesson learnt!

 

nice one spud thats what i wanted to hear

[spudulike]

nice one spud thats what i wanted to hear

 

You should have asked before and saved yourself £70:001_rolleyes:

 

Buy this piston off Leo - top guy and 5-7 days turn around - Piston Kit fit STIHL 064, 064 R, 064 RW, MS 640 (52mm) | eBay

[[email protected]]

new bars today

SHINEY NEW THINGS!!!!!!!!!!!!!!

3x 15" Oregon pro-lite bars arrived today for

346xp

55

450 x torq

oh and new 24" husq chain for 395xp

[[email protected]]

new bars today

SHINEY NEW THINGS!!!!!!!!!!!!!!

3x 15" Oregon pro-lite bars arrived today for

346xp

55

450 x torq

oh and new 24" husq chain for 395xp

:001_smile:

[lakeyboy]

just had another look at the 064 there is a minute gap between the cylinder wall and piston at the top of the exhaust port take it thats where my compression is going ? also as i mentioned before i totally rebuilt the saw and after looking closley i found a small gap where the crankcase gasket meets the bottom of the cylinder but it is very small and that would not affect compression ? just vacuum and pressure ?

[spudulike]

just had another look at the 064 there is a minute gap between the cylinder wall and piston at the top of the exhaust port take it thats where my compression is going ? also as i mentioned before i totally rebuilt the saw and after looking closley i found a small gap where the crankcase gasket meets the bottom of the cylinder but it is very small and that would not affect compression ? just vacuum and pressure ?

 

:confused1:Huh - a picture is clearer than a thousand words - especially if you stick a big arrow on it to what you have!

 

Any leak between the base of the cylinder and the crankcases will cause an air leak which may possibly seize the engine or will just cause idle and running issues - typically holding on to the revs and unstable idle.

 

Compression is formed when the piston rings pass the exhaust port on the upward stroke, loss of compression can be caused by piston to bore wear/clearances, damaged bore, damaged piston, too much squish worn rings, scored bore etc

 

I am not quite sure what you are describing - any base gasket leak needs sealing 100% and you need to make 145+psi for reliable combustion.

 

Get me a photo of these "gaps" ...if you can get a 3 thou feeler gauge between the piston and the bore, you have clearance problems!

[lakeyboy]

I'll get pic up ASAP I took the saw to the local dealer today for comp test won't have back till Monday but he said just by pulling it over that there's plenty of compression I disagree personally there is still less than the standard 064 that my boss owns ! this is doing my head in a bit now

[spudulike]

I'll get pic up ASAP I took the saw to the local dealer today for comp test won't have back till Monday but he said just by pulling it over that there's plenty of compression I disagree personally there is still less than the standard 064 that my boss owns ! this is doing my head in a bit now

 

Man, a compression test is a five minute job - thank the lord you didn't ask for a rebuild - you would be in retirement before getting it back:lol: