What's on your bench today?

[spudulike]

Hi Spud I have a 029 super that rattles like a bag of nails when its pulled over. I have taken the exhaust off and there were large ammounts of carbon deposits other than that the piston doesnt look to bad apart from a small lip around the edge of the crown the rings seem to move in and out if pushed with a lolly stick more than I thought they should and the compression seems lower than normal, the saw seems to have done very little work and Im puzzled

 

Plus the drive sprocket is 3/8 but the only spare bar I have is .325 would you replace the drive to .325 or replace the bar to 3/8.

 

 

Any ideas would be appreciated

 

Sorry for missing the cry for help, the easy bit first - I would use the 0.325 bar mainly because the saw will not be a power house and 0.325 will be less power hungry than the 3/8 and probably smoother in operation IMO.

 

The rattling - does the saw run? Has it run and expired?

 

My thinking on the rattle - could be a clutch spring that has expired and the clutch shoe is now loose - take the clutch drum off and take a look - the clutch centre/boss may have split in two - just had a 034 I purchased with this.

 

If this is OK then it may be more serious - the big end can expire - serious and will cause low compression - you can usually tell by turning the flywheel back and forth and the piston will stay in place with much to and forth movement of the flywheel.

 

The small end bearing may have expired - possibly serious and you will get similar symptoms as the above.

 

I have only had one big end failure and no small end fails, the big end one is still in a box awaiting some time:thumbdown:

 

My thoughts are that the clutch has busted but use this as a guide.

 

Also check the flywheel isn't clouting the coil on rotation.

 

To get rid of the carbon, get the piston to cover the port, scrape the carbon off without damaging the piston, turn the saw over so the port faces downward and blast a bit of WD40 or similar in the port to wash it out. raise the piston a little to make sure as much of the crap has been washed out as possible. Use a cotton bud to clean any further crap out.

 

Compression - may be time for a gauge - you can generally tell by pulling the engine over slowly, lots of spongey feeling as the engine pulls over TDC is good, if it pulls over TDC with ease than you have issues.

 

 

Good luck, let us know how you get on.

Edited August 14, 2012 by spudulike

[GardenKit]

Gardenkit! any chance you can help out with my question on the previous page ? I recon spuds gone up the pub

Call in the reserve:biggrin:

 

No definite answers Jammy, but a few questions for starters.

 

Has it ever run for you? (or is it 'new' to you?)

Does it start, or does it only rattle on cranking?

"the compression seem low" ... has it been tested, if so what is it?

 

As to which bar, I guess it depends on what you want to do with it.

 

Maybe Spud is back from t'pub by now!!

 

edit,Yes he is!!

[spudulike]

Call in the reserve:biggrin:

 

No definite answers Jammy, but a few questions for starters.

 

Has it ever run for you? (or is it 'new' to you?)

Does it start, or does it only rattle on cranking?

"the compression seem low" ... has it been tested, if so what is it?

 

As to which bar, I guess it depends on what you want to do with it.

 

Maybe Spud is back from t'pub by now!!

 

edit,Yes he is!!

 

Think there is an Echo on this site and not the Japanese type, we either both know what we are talking about or are both equally stupid:lol:

[GardenKit]

Think there is an Echo on this site and not the Japanese type, we either both know what we are talking about or are both equally stupid:lol:

I always feel daft when I take too long posting and someone else beats me to it (often you:biggrin:)

 

I reckon we can get to the bottom of most things between us, eventually, if we ask the right questions.

[Pat Ferrett]

Think there is an Echo on this site and not the Japanese type, we either both know what we are talking about or are both equally stupid:lol:

 

You guys make a great double act

[Pat Ferrett]

The saw is new to me and I didnt ask its history as it was sols as seen.

I removed the exhaust and held the piston while gently turning it over and there is no play in either the big or small ends, the coil is a good idea and ill check it in the morning, as for the carbon it was only build up in the exhaust but the port was clean.

Ill keep you posted

[spudulike]

The saw is new to me and I didnt ask its history as it was sols as seen.

I removed the exhaust and held the piston while gently turning it over and there is no play in either the big or small ends, the coil is a good idea and ill check it in the morning, as for the carbon it was only build up in the exhaust but the port was clean.

Ill keep you posted

 

The news about the ends is good, one more thing to check is up and down play in the crankshaft bearings by waggling the crankshaft up and down both ends.

 

From what you have said, by money is on the clutch but inspection under both the clutch drum and recoil cover would be good - sounds like the 034 I got - pics on htis thread....somewhere - getting rather long:thumbup:

 

If Gardenkit and I are a double act, I am the tall good looking one:lol:

[Johny Walker]

Compression should be around 90 to 100psi, quite a bit lower than a 2 stroke so it wont seem much in comparison.

 

Its also difficult to judge as the engine has an automatic decompressor to ease starting effort.

 

You CAN do a compression test, but you MUST pull it very fast on the recoil several times to get past the decompressor.

 

The valves need regular adjustment on these engines. They tend to become loose, limiting the amount of time they are open.

 

To adjust, find the little arrow between the flywheel fins and point it to the RH ignition module mounting bolt. Make sure the valves are rocking. If they are overlapping (one open, one closed) rotate another 360 deg until they are rocking (both closed).

 

Adjust to 0.1mm +- .02mm, using a feeler cut down to about 3mm to fit between the side pressings of the rockerarm. Rotate twice and check again.

 

Unfotuneately, as its a 4 stroke engine you cannot check the piston through the exhaust port as the exhaust is passed out throught the valves to the exhaust port.

 

Good luck

 

CHEERS FOR THAT HAVE PRINTED IT OF

[GardenKit]

You guys make a great double act

 

......

[spudulike]

......

 

Suppose it is better than the Krankies:lol: