Jonsered 2171 build disaster

[astnmacgto]

I have a mahle jug thats on the saw i just bought, it's kind of a hermie saw and id like to know what numbers should designate the bore size.

I have 3 jugs here total that all say 50zk6 on them. This is supposed to be a 75cc top end on the saw and I'm pretty sure one of my other jugs measures 48mm. This jug has 50 scratched on the top from previous owner.

What number tells you the difference between bore sizes?

Thanks guys, I'm going to bed now, ill catch up on this tonight.

 

[jacob j.]

50ZK6 is a Mahle ID number (I believe). The two 51.4mm jugs I have say "50 ZK6 W++", the ++ probably indicating an oversize bore. I have one that says 50ZK6 W and one that says 50ZK6 W+ but both of those are 50mm bore.

You can also look at the bottom of the transfer ports- Randy has posted many pictures depicting the difference in the bottom transfers between the 50 and 51.4mm jugs.

 

[Angelr]

Tengo una jarra de mahle que está en la sierra que acabo de comprar, es una especie de una sierra de hermie y me gustaría saber qué números deben designar el tamaño del agujero.

Tengo 3 jarras aquí total que todos dicen 50zk6 en ellos. Se supone que esto es un extremo superior de 75cc en la sierra y estoy bastante seguro de que una de mis otras jarras mide 48mm. Esta jarra tiene 50 rayado en la parte superior del propietario anterior.

¿Qué número indica la diferencia entre los diámetros?

Gracias chicos, me voy a la cama ahora, ponerse al día sobre esto esta noche. [/ QUOTE]
Some mahle cylinders of 365xp came with closed tranfers, according to I think, it is the cylinder mold 372 of 50mm but with a hole of 48mm, that is why the cylinder on the outside puts 50, then there are the open transfers, I have seen them with admission square and round

 

[Outback]

When they were new you would often see a blue or black ink 48 50 or 51.4 on the top of the cylinder opposite the spark plug under the top cover, Its not stamped and doesn't appear well after the cylinder is dirty. That,s why the previous guy scratch a mark back on. The only way to know is to pull the jug in my limited opinion.

 

[Angelr]

Cuando eran nuevos, a menudo se veía una tinta azul o negra 48 50 ó 51,4 en la parte superior del cilindro frente a la bujía debajo de la cubierta superior, no está estampada y no aparece bien después de que el cilindro esté sucio. Es por eso que el tipo anterior rasca una marca de nuevo. La única manera de saber es tirar de la jarra en mi opinión limitada. [/ QUOTE]
The cylinders of other models also bring that blue dot, I think it is a quality control that passed that cylinder and mark it with that point

 

[blsnelling]

Why not just measure them?

 

[Chainsaw Jim]

I have a mahle jug thats on the saw i just bought, it's kind of a hermie saw and id like to know what numbers should designate the bore size.

I have 3 jugs here total that all say 50zk6 on them. This is supposed to be a 75cc top end on the saw and I'm pretty sure one of my other jugs measures 48mm. This jug has 50 scratched on the top from previous owner.

What number tells you the difference between bore sizes?

Thanks guys, I'm going to bed now, ill catch up on this tonight.

You can use a set of calipers with a depth probe to measure the bore through the exhaust. Rest the caliper up against the slightly exposed piston and send the probe in until it stops against the back center of the cylinder. That will be a very accurate reading.

 

[blsnelling]

You can stick a toothpick, straw or anything similar in the exhaust port, pinch it with the piston, then measure that.

 

[67L36Driver]

Popsicle stick works the best. Round end.

Also use them to install rings.[emoji108]

 

[Chainsaw Jim]

It's very easy to make a 1.4mm error when using a toothpick or stick with this model because the exhaust roof slopes down so sharp you can't keep a stick or toothpick straight enough while pinning it to the roof with the piston to mark it.
A popsicle stick would be ideal to mark it against the exhaust floor. The piston would need to be locked level at the exhaust floor to keep the end of stick straight against the backside of the wall.

 

[old guy]

I'm with chainsaw Jim, I use the caliper.

 

[Wagnerwerks]

I'm a popsicle stick guy when the top end is on the saw.

 

[astnmacgto]

Thanks guys, the saw showed up last night while I was at work so I didn't get to pull it out of the box til it was time for me
To go to bed, I was hoping there was a specific set of numbers on the jug that would tell me easily as I won't have time to measure it until tomorrow night.

Guy advertised it as a big bore saw which had me worried but it is definitely oem cylinder and I'm sure it's a quality piston as well because the guy said he bought it from a dealer that did the work, it's been changed over to a metal intake clamp and everything else is oem on the saw

 

[astnmacgto]

I'll get it measured and post up here my results.

 

[jacob j.]

The 372 always had the metal intake clamp.

 

[astnmacgto]

The 372 always had the metal intake clamp.

Well then, I was wrong haha.

I've never had a 2171 before

 

[astnmacgto]

Well, I couldn't get an accurate measurement due to the slope of the exhaust port. But I did notice that someone was in there messing around with the upper transfers. Exhaust looks stock. Maybe it was just my flashlight but they didn't look very uniform or well cut. So I will be pulling the jug after I get some timing numbers, piston looks good. It appears there is no base gasket either.

So I will be putting this on slight hold til I get my poulan 335 rebuilt and get a few parts on my 246 husky. Shouldn't take long as I have all the parts and finally a day off tomorrow.

 

[astnmacgto]

Here is what I found inside this sucker....

1. Here is a sliver of what is left of the integral flywheel key.... and the flywheel

2. Absolutely horrid machine work on the base..... tis neither square nor is it centered

 

[astnmacgto]

3. Pics of the squish band, doesn't look too bad....

4. Pic of the lower transfers....

 

[astnmacgto]

5. Pics of the uppers.....

It's hard to tell but it appears that someone set the cylinder at an angle and used an end mill because the roofs are angle and there are prominant swirl marks where they were cut.