Porting a Chinese G621 Clone

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I do a
yeah- my saws are tools, not a religion. and the only "new" epa approved saw that i care for at all is the husky 575. that's not because it's all orange but because of its wide power band and abundant torque.

regarding your practice of blue-printing your saws before they are deployed, it sounds like a good idea but there are a couple of things that would be hard to catch if you didn't have the hard experience of dealing with them, the muffler failures, the air filters that don't, and who would expect a flywheel-side crank seal to fail after a couple of hours. tt's like the saw was trying to find a new way to suck in more saw dust![/QUOTE
 
Have had no problem with the fly wheels after balancing . The crank seals will hold once the crank is balanced and true .
The filtration system is a joke , try a husky filter setup and adapt it to your existing carby .
 
If anyone isn't acquainted with the rout-a-burr tool for sharp edges
You're in for a slight treat of more tool acquisition disorder.
It's one more handy tool for spots where the old triangular deburring knife
is a bit hard on the carpal tunnel or You just want the ease with which it can radius
a hole, slot or edge.

http://www.penntoolco.com/catalog/products/products.cfm?categoryID=1710
 
Do you guys sleeve your saws maybe doweling the cylinder .
Basically has any body been outside the box with there saws .
Being from a performance world testing the boundaries are a day to day thing at work .
 
Well i just had a weigh in for my Baumr-ag saws. The Sx72 weighed it at 7Kg or 15 lbs with the 20" bar and 5.5Kg without bar. My SX62 weighed the same and the SX45 was .5Kg lighter. TI he 62cc saw that we get here is a different design to the 72cc. The 62cc saw needs to have the impulse hose modified so that the saw doesnt lean out when it warms up and the 45cc saw is the same. I just threaded a piece of thin copper pipe inside the impulse hose and bent it to shape to stop it from sucking in an closing off when the motor warms up, and the saws have worked perfectly since.
I have seen both 62cc saws for sale on eBay here. One is the G621-based saw I have, and the other is based on the G5000 design but bored and stroked. I stayed away from the latter one as the G5000 used a Walbro WT series carb, and it appears the larger displacement clones stayed with a Chinese version of it - and I think that's too small for a 62cc saw. Otherwise those appear to be nice designs, and I think the 52cc must be the most common of all Chinese saws. They have made them with so many variations of color and cover shapes.
 
BTW, something I noticed on mine is that the date code on the casting shows January of 2008. Now that is just for the raw casting, but still possibly an indication that these saws are actually a few years old. Or maybe that they never move the thingy in the mold!
IMG_1133-800date.jpg
 
Well i just had a weigh in for my Baumr-ag saws. The Sx72 weighed it at 7Kg or 15 lbs with the 20" bar and 5.5Kg without bar. My SX62 weighed the same and the SX45 was .5Kg lighter. The 62cc saw that we get here is a different design to the 72cc. The 62cc saw needs to have the impulse hose modified so that the saw doesnt lean out when it warms up and the 45cc saw is the same. I just threaded a piece of thin copper pipe inside the impulse hose and bent it to shape to stop it from sucking in an closing off when the motor warms up, and the saws have worked perfectly since.

it sounds like the baumr saws are significantly different from the richmonds sold over here. they seem to be built a lot better, but our 62cc saws have the impulse line in the carb body, no plastic tube. as long as your gaskets hold up everything is fine. chris, thanks for the heads up. i'll have a look. it might be hard to find a replacement for the av mounts.
 
it sounds like the baumr saws are significantly different from the richmonds sold over here. they seem to be built a lot better, but our 62cc saws have the impulse line in the carb body, no plastic tube. as long as your gaskets hold up everything is fine. chris, thanks for the heads up. i'll have a look. it might be hard to find a replacement for the av mounts.
Search on ebay for "62cc chainsaw". A complete mount kit is about $20.
 
I replaced the A/V mount, it was not difficult. Here is the bad one (sorry for the focus problem):
IMG_0542-800.jpg
You can see it ripped right behind the end flange, which goes up against the edge here:
IMG_0543-800.jpg
I ended up using a spherical stone on the Dremel to take that edge off:
IMG_0544-800.jpg
I lubed the new one with a bit of canola oil, as that's what's going to get all over it anyway from the bar - it went in no problem. The screw is really tiny and has me a bit concerned.

My new loop of Oregon 75DP arrived, so I can use the 25" bar that came with it again:
IMG_0547-800.jpg
And yes, 0.063" drops right in that bar, fitting much better than 0.058". This is the first loop of Oregon chain that has been well enough ground to use as is - not perfect but good enough that I didn't want to go over that many cutters!
IMG_0548-800.jpg
 
Well, once again the saw ran great but suffered yet another failure/missing part issue. The thing oils quite well, but it started oiling even more enthusiastically - blowing it out around the top cover, and just about everywhere else. It was covered with bar oil. What a mess! At first I thought it was the cap, but soon realized that was not the problem. It was running out behind the coil.

After removing the coil I found a small duckbill valve laying in a recessed well (I should have taken pictures but was running out of time). I popped up the IPL for the real G621 on my iPhone (handy), and found that there should have been a retaining clip and a seal/filter, but those were nowhere to be seen.

The duckbill sits in a small hole at the bottom of a cast well about 0.395" in diameter. Putting it back in the hole was not problem, but I needed something to retain it. I decided to drill a hole in a block of wood with a size "Y" bit, and then cut out a small piece of spare spark screen. I put that over the hole, and pushed it in with the back end of a size "W" bit, forming a cap. Then I trimmed off the excess, and pushed the screen into the well, up against the duckbill valve. It's pretty stiff screen and I think it will hold it in. It sits in there like the filter screen in a carb.

There is a little ramp molded onto the back of the coil that appears to be intended to hold something over the tank vent, so I cut out a piece of old air filter foam and set it over the hole. The coil holds it in nicely. Cleaning the saw up took more time than fixing it, but fortunately it was canola oil.
 
That was a very interesting and informative 14 page read! Thanks Chris-PA for the thread. I don't think I'll be buying any saws in the near future as I have 5 now but I think I'd seriously consider one of these as a "beater"? I have a new MS391 and a recently rebuilt MS360 so another 60cc class saw isn't something I need but a 70+cc, maybe...
 
i will report yet another failure. the chain brake detent wore out. its the small steel lever that is attached to the chain brake spring. it got to the point that the chain brake would trip if you looked at it funny. i took out the lever and tried to reshape it with a file several times but couldn't get it quite right. the saw is usable now but there will be no chain brake until a spare part arrives from redmax. i think the part cost $2 and shipping $8. the odd thing is that i never use the chain brake. i don't think it had 10 cycles on it. it failed immediately after i replaced the flywheel side crankshaft seal which only had a few hours on it. it's a pain to remove and replace the chain brake spring. i'll probably devise and fabricate a tool before i do it again.

good news is that the saw seems to be sucking less chips now. i think that the bad seal was sucking sawdust into the case which was blowing back thru the carb. i'm also having a problem similar to chris's with the chain running thru the clutch area. the chain won't run backwards and it is wearing a groove on the inner chain plate. the chain plate looks like it was intended to fit a stihl rather than redmax. the bar appears to be at some other than 90 degree angle to the crank shaft. i have officially awarded this saw POS status. i cannot recommend it. you will spend less money if you just buy a good used european or japanese saw, echo, stihl or husky. This saw has never run more than an hour without a catastrophic (and expensive) failure. i've spent a lot more time working on this saw that with it.
 
i will report yet another failure. the chain brake detent wore out. its the small steel lever that is attached to the chain brake spring. it got to the point that the chain brake would trip if you looked at it funny. i took out the lever and tried to reshape it with a file several times but couldn't get it quite right. the saw is usable now but there will be no chain brake until a spare part arrives from redmax. i think the part cost $2 and shipping $8. the odd thing is that i never use the chain brake. i don't think it had 10 cycles on it. it failed immediately after i replaced the flywheel side crankshaft seal which only had a few hours on it. it's a pain to remove and replace the chain brake spring. i'll probably devise and fabricate a tool before i do it again.

good news is that the saw seems to be sucking less chips now. i think that the bad seal was sucking sawdust into the case which was blowing back thru the carb. i'm also having a problem similar to chris's with the chain running thru the clutch area. the chain won't run backwards and it is wearing a groove on the inner chain plate. the chain plate looks like it was intended to fit a stihl rather than redmax. the bar appears to be at some other than 90 degree angle to the crank shaft. i have officially awarded this saw POS status. i cannot recommend it. you will spend less money if you just buy a good used european or japanese saw, echo, stihl or husky. This saw has never run more than an hour without a catastrophic (and expensive) failure. i've spent a lot more time working on this saw that with it.
My chain brake was getting a little touchy too, but I cleaned up the shape of that piece with a small diameter stone on my Dremel. Basically I gave it just a little more defined pocket. It seems to work nicely now - we'll see if it holds up.

Since I put the clutch on correctly I have no more issues with the chain. Maybe you just need to bend the lower edge of the inner bar plate in a bit? I've had to do that on some other saws. The 0.058" chain in a 0.063" bar may be contributing.

The assembly is surely disappointing. I would rather have had a box of parts - but then it would still need to have ALL the parts...
 
My chain brake was getting a little touchy too, but I cleaned up the shape of that piece with a small diameter stone on my Dremel. Basically I gave it just a little more defined pocket. It seems to work nicely now - we'll see if it holds up.

Since I put the clutch on correctly I have no more issues with the chain. Maybe you just need to bend the lower edge of the inner bar plate in a bit? I've had to do that on some other saws. The 0.058" chain in a 0.063" bar may be contributing.

The assembly is surely disappointing. I would rather have had a box of parts - but then it would still need to have ALL the parts...

yeah, i need to go back and reread your posts regarding the clutch. do you know which page it is on? we're at 15 now. that's a lot to go thru. my memory is that you flipped the clutch over but that didn't work for me. the first major problem i had with this saw was a non-functional clutch. the clutch bearing was frozen to the shaft with (perhaps?) thread locking compound.

i got this thing just to have something to experiment with in those late winter months when cabin fever was setting in but it's nearly summer now. maybe i'll remount the POS bar and chain that it came with and use it to make a wind vane for outside my shop..
 
yeah, i need to go back and reread your posts regarding the clutch. do you know which page it is on? we're at 15 now. that's a lot to go thru. my memory is that you flipped the clutch over but that didn't work for me. the first major problem i had with this saw was a non-functional clutch. the clutch bearing was frozen to the shaft with (perhaps?) thread locking compound.

i got this thing just to have something to experiment with in those late winter months when cabin fever was setting in but it's nearly summer now. maybe i'll remount the POS bar and chain that it came with and use it to make a wind vane for outside my shop..
If you used it as a weathervane it would probably point the wrong way.

The backwards clutch issue was here: http://www.arboristsite.com/communi...hinese-g621-clone.253359/page-11#post-4790325 I had some other things I was trying before I discovered the real problem, but those were all erroneous. The problem I was having is that the backwards clutch pushed the drive sprocket out too far, and the face of the clutch drum was outside of the plane of the bar. That made the chain go through a nasty S curve as it came off the tail of the bar, and on the chain that came with it the inner cutters dragged across the drum face.

With the clutch on correctly the drive sprocket is moved inboard. Now the chain holds the rim well centered, and it floats with clearance on both sides. I do believe I added an additional flat washer behind the outer left hand nut, as there seemed to be too much slop to the drive sprocket.

The oil tank vent seems to be working well, and the chain brake is also working nicely - for now. I am concerned that the pawl is improperly heat treated and will wear badly again, so I may go ahead and order the real piece from RedMax.

It ran great and had no problems today. Started right up, ran great, oiled the 25" bar well at about 1/2 setting, and oil went where it was supposed to. The chain brake didn't put itself on every time I blurbed the throttle either. I used it to noodle up some large white ash rounds with knots that have been sitting for 2 years - they were quite hard and about 21" long. It made the saw work that's for sure, but it pulled well until the chain went dull.
 
If you used it as a weathervane it would probably point the wrong way.

The backwards clutch issue was here: http://www.arboristsite.com/communi...hinese-g621-clone.253359/page-11#post-4790325 I had some other things I was trying before I discovered the real problem, but those were all erroneous. The problem I was having is that the backwards clutch pushed the drive sprocket out too far, and the face of the clutch drum was outside of the plane of the bar. That made the chain go through a nasty S curve as it came off the tail of the bar, and on the chain that came with it the inner cutters dragged across the drum face.

With the clutch on correctly the drive sprocket is moved inboard. Now the chain holds the rim well centered, and it floats with clearance on both sides. I do believe I added an additional flat washer behind the outer left hand nut, as there seemed to be too much slop to the drive sprocket.

The oil tank vent seems to be working well, and the chain brake is also working nicely - for now. I am concerned that the pawl is improperly heat treated and will wear badly again, so I may go ahead and order the real piece from RedMax.

It ran great and had no problems today. Started right up, ran great, oiled the 25" bar well at about 1/2 setting, and oil went where it was supposed to. The chain brake didn't put itself on every time I blurbed the throttle either. I used it to noodle up some large white ash rounds with knots that have been sitting for 2 years - they were quite hard and about 21" long. It made the saw work that's for sure, but it pulled well until the chain went dull.


Right, i flipped the clutch today. it helped a little but the chain still doesn't make it thru the drive sprocket correctly. it will hang occasionally when i run the chain backwards. i did use the saw today, dropped a good sized russian olive. no debris accumulated behind the air filter so i am fairly certain that my problem with chips after the filter was due to the flywheel side crank seal, bizarre. thanks for the pointer re. your clutch woes. i need to move on and concentrate on trees more than saws.
 
Man you guys much love punishment or something but I think you two have done a great service for the readers of this site. That is unless you are into torture don't buy on of these saws.
 
Man you guys much love punishment or something but I think you two have done a great service for the readers of this site. That is unless you are into torture don't buy on of these saws.
Given the missing parts and things like the backwards clutch, I wouldn't recommend one. OTOH I've certainly read about people discovering nasty surprises in used saws that cost at least as much. At this point I've got a nice light 62cc saw that runs quite well.

I'm impressed with the G621 design - with the exception of the air filter, but in fairness the real one probably fits & works better.
 
Back
Top