Porting a Chinese G621 Clone

[Chris-PA]

actually it's clearly evident that it's entering under the bottom of the filter, especially in the back. I'm wondering if the filter gets cocked when the knob is tightened, creating a gap. you can see from the indentations left by the knob and filter that the paper gasket is sealing well. the shape is just to keep it from spinning when the knob is tightened. I guess I'll have to take it down again and see if I can find a cause. It's interesting that you're not having the same problem.

It's too bad because the saw really does run well and with its light weight, it's a pleasure to operate.

Oh, OK - I guess I can see what you mean. I'd still recommend trying a stop tube as I made - that would limit how much force the knob can put on the filter, and perhaps keep it from tipping? Once the knob is push on the filter hard enough to seal it, pushing it down further will only distort something. I made mine just shorter than the top of the filter.

 

[heyduke]

have you tried a little thick grease on the ill fitting parts? Used to do well on dirt bike intake systems. Not pretty but kept the big chunks out.

yes

 

[Chris-PA]

yes

I was off today and had a change to run the saw a bit. Here is the filter situation after 1-1/2 tanks:





This saw is a joy to run with a 20" bar.

 

[heyduke]

I was off today and had a change to run the saw a bit. Here is the filter situation after 1-1/2 tanks:

This saw is a joy to run with a 20" bar.

Thanks for the fotos. i guess there is some major defect with my filter/air intake. the fotos i posted earlier were after running it maybe five minutes. it sucks in sawdust like a vacuum cleaner.

I finally looked at a g621 for comparison. it has a far superior design. while the richmond has a simple slip over air filter the redmax has a stepped flange/filter joint. that means any debris has to go thru a tight 90 degree angle. so, i'm thinking i will just order a redmax filter ($45) and air intake horn ($7.50). i'm thinking that the asian companies got their hands on some old and/or defective injection molds. i also noticed that redmax upgraded their air filter at least once, so perhaps this was a problem for them at some time.

 

[Chris-PA]

Thanks for the fotos. i guess there is some major defect with my filter/air intake. the fotos i posted earlier were after running it maybe five minutes. it sucks in sawdust like a vacuum cleaner.

I finally looked at a g621 for comparison. it has a far superior design. while the richmond has a simple slip over air filter the redmax has a stepped flange/filter joint. that means any debris has to go thru a tight 90 degree angle. so, i'm thinking i will just order a redmax filter ($45) and air intake horn ($7.50). i'm thinking that the asian companies got their hands on some old and/or defective injection molds. i also noticed that redmax upgraded their air filter at least once, so perhaps this was a problem for them at some time.

I'll be interested to see some pictures of that if you buy one - I have no G621 available to look at.

 

[heyduke]

I'll be interested to see some pictures of that if you buy one - I have no G621 available to look at.

Well, I looked again today and decided I must have been hallucinating. I see no step. The Redmax does seal though.

redmax filter bottom



Redmax filter top, note that this is quite different from the Richmond:



Here's what I call the air horn. I think Zenoah misnames it a manifold. If the plastic wasn't black you could see how clean it is inside.



Here's a foto of the richmond, showing the gross misalignment of the filter cover to the tank/handle. In fact it won't even close to the cylinder cover on the left hand side, leaves a gap of about 2 or three mm:



I agree regarding the benefits of a 20" bar. I have a spare d176 but its 24". I think I'll go with a 20 Rollomatic if I ever get this thing operational. I suppose that If this was your only saw and intended to be used after the hurricane, a 24" bar would make sense, but I have bigger saws for big wood. And a 20" bar would balance much better. I rankles me when I set the saw down and the tip buries itself in the dirt, the trip-on-your-own-duck syndrome.

 

[Chris-PA]

Well, I looked again today and decided I must have been hallucinating. I see no step. The Redmax does seal though.

redmax filter bottom


Redmax filter top, note that this is quite different from the Richmond:


Here's what I call the air horn. I think Zenoah misnames it a manifold. If the plastic wasn't black you could see how clean it is inside.


Here's a foto of the richmond, showing the gross misalignment of the filter cover to the tank/handle. In fact it won't even close to the cylinder cover on the left hand side, leaves a gap of about 2 or three mm:



I agree regarding the benefits of a 20" bar. I have a spare d176 but its 24". I think I'll go with a 20 Rollomatic if I ever get this thing operational. I suppose that If this was your only saw and intended to be used after the hurricane, a 24" bar would make sense, but I have bigger saws for big wood. And a 20" bar would balance much better. I rankles me when I set the saw down and the tip buries itself in the dirt, the trip-on-your-own-duck syndrome.

Thanks for the pictures. I dealt with the misalignment shown in the last picture by rotating the cylinder on reassembly, and it all lines up properly now.

I actually bought the stick-on seal shown here:

but the top of the Chinese filter is dished in this area, not flat like the Zenoah filter, so I did not put it on yet. I may give it a try, as the top cover is chafing the top of the filter. The Zenoah filter is pretty clearly a different shape - I'm surprised as I don't see any good reason for them having changed it, unless as you say it is a copy of an earlier version or some such.

 

[HarveyCat]

Regarding the fuel cap, husqvarna has some caps that will work. I like the fuel cap from a 575. The stock caps and gaskets are sketchy. Replace them and you'll find you use less fuel.

My cap with a Home Depot quick fix still works -- but I bought a backup -- I hope that Husqvarna 575 cap has worked out well for you -- I just ordered one on ebay for $5.95
http://www.ebay.com/dsc/i.html?_from=R40&_sacat=0&LH_TitleDesc=1&_nkw=537215202&_sop=15

This site says it fits a lot
http://www.ereplacementparts.com/tank-cap-p-615169.html

 

[Chris-PA]

Well, things have been falling off my Chinasaw lately - the felling dog and the carb bolts came lose, but a couple of exhaust problems were more serious. I've been adding lock washers to things like the dog, and Loctite fixed the carb bolts. The other day the muffler support bracket fatigue failed and cracked off where the case bolt goes through. It was not that hard to fix - I made a little L shaped piece and silver soldered it on:

So today I gave it a test run after I got some other work done, and right before the skies opened up. While I was running back to the barn I heard a nasty rattle, and eventually determined it was coming from inside the muffler. I had not planned on doing a muffler mod, but this one decided to self mod. Here is what's inside:

There's plenty of large holes in the main baffle, and the outlet box is decent. Unfortunately it was no longer attached, as the brazing broke:

I decided to put it back together with the main baffle. I silver soldered it back - it's not too pretty a job, but it's functional. No holes:

Painted:

Reinstalled:

I guess if I keep fixing stuff that breaks or was not installed right I'll get past it! It does still run like a top.

 

[heyduke]

Well, things have been falling off my Chinasaw lately - the felling dog and the carb bolts came lose, but a couple of exhaust problems were more serious. I've been adding lock washers to things like the dog, and Loctite fixed the carb bolts. The other day the muffler support bracket fatigue failed and cracked off where the case bolt goes through. It was not that hard to fix - I made a little L shaped piece and silver soldered it on:
[
So today I gave it a test run after I got some other work done, and right before the skies opened up. While I was running back to the barn I heard a nasty rattle, and eventually determined it was coming from inside the muffler. I had not planned on doing a muffler mod, but this one decided to self mod. Here is what's inside:

There's plenty of large holes in the main baffle, and the outlet box is decent. Unfortunately it was no longer attached, as the brazing broke:

I decided to put it back together with the main baffle. I silver soldered it back - it's not too pretty a job, but it's functional. No holes:
Painted:

Reinstalled:

I guess if I keep fixing stuff that breaks or was not installed right I'll get past it! It does still run like a top.

nice job on the muffler. if you don't need to fill wide gaps silver solder can be stronger than bronze.

i suffered a major setback yesterday.. the saw quit burbling at wfo and i knew it was running lean. the cylinder cover was hot to the touch.when i tried to enrich the carb, turning the H screw had no effect, even backed out 4 or 5 turns. i have an air leak somewhere. i pulled off the carb and isolator. the mounting bolts were tight and when disassembled everything looked fine. cylinder bolts were tight. I just put new sealer under the cylinder, used the permatex equivalent of yamabond. i don't think there's a problem there. i don't like to jump to conclusions, but i suspect the pto side crankshaft seal, don't know if i will bother to pressure test it. i'm about to give up on this project and officially designate it a POS. your report on the muffler failure reinforces my gut. no complaints, this was an experiment but i think it may be time to wrap it up. my saws are all work saws and dependability is a requirement.

 

[Chris-PA]

nice job on the muffler. if you don't need to fill wide gaps silver solder can be stronger than bronze.

i suffered a major setback yesterday.. the saw quit burbling at wfo and i knew it was running lean. the cylinder cover was hot to the touch.when i tried to enrich the carb, turning the H screw had no effect, even backed out 4 or 5 turns. i have an air leak somewhere. i pulled off the carb and isolator. the mounting bolts were tight and when disassembled everything looked fine. cylinder bolts were tight. I just put new sealer under the cylinder, used the permatex equivalent of yamabond. i don't think there's a problem there. i don't like to jump to conclusions, but i suspect the pto side crankshaft seal, don't know if i will bother to pressure test it. i'm about to give up on this project and officially designate it a POS. your report on the muffler failure reinforces my gut. no complaints, this was an experiment but i think it may be time to wrap it up. my saws are all work saws and dependability is a requirement.

Well, that's too bad. It's a pretty simple intake setup, so if it's not leaking there or at the cylinder base it does not leave many other options.

 

[Chris-PA]

nice job on the muffler. if you don't need to fill wide gaps silver solder can be stronger than bronze.

i suffered a major setback yesterday.. the saw quit burbling at wfo and i knew it was running lean. the cylinder cover was hot to the touch.when i tried to enrich the carb, turning the H screw had no effect, even backed out 4 or 5 turns. i have an air leak somewhere. i pulled off the carb and isolator. the mounting bolts were tight and when disassembled everything looked fine. cylinder bolts were tight. I just put new sealer under the cylinder, used the permatex equivalent of yamabond. i don't think there's a problem there. i don't like to jump to conclusions, but i suspect the pto side crankshaft seal, don't know if i will bother to pressure test it. i'm about to give up on this project and officially designate it a POS. your report on the muffler failure reinforces my gut. no complaints, this was an experiment but i think it may be time to wrap it up. my saws are all work saws and dependability is a requirement.

Maybe it's not an air leak - if something is limiting fuel flow either to the carb or in the carb you might not be able to feed more fuel by opening the H screw.

 

[heyduke]

Maybe it's not an air leak - if something is limiting fuel flow either to the carb or in the carb you might not be able to feed more fuel by opening the H screw.

It certainly wouldn't surprise me to find that the carb is defective too but it's not the filter or a bad fuel line. it doesn't act anything like that. it acts like a saw that is running too lean due to an air leak. actually i've been worried about it since the first day i had it because i could never get the idle low enuff to kill it. the lowest it would run is 2700rpm with the adjustment screw off the throttle lever. now it won't idle slowly enuff to fully disengage the clutch. anyway, i'm in the process of pressure checking it now. i have to make up the two plates, one with a hose barb. i really don't know why i'm bothering. my gut is telling me to leave it in the bed with the tailgate open in the walmart parking lot. but my chucking furiosity is driving me in another direction. as i said previously i don't think that this is a good work saw. i don't think it would be likely to make it thru a job without breaking something. anyone reading this, it's a waste of time and money.

anyway, looking at your excellent clutch tool, i decided if i made a tool with three dogs, like yours, only two dogs would be doing all the work. so, i came up with this. th dogs are 10mm allen screws. the handle is 3/16" thick, part of a hinge for a large gate. it has more the 12" of moment so getting the clutch loose was easy. (it was on backwards)




here's the pto-side seal. it looks like it may have been jammed in crooked. the rubber is tore up on one side, around 8:00 o:clock

 

[Chris-PA]

It certainly wouldn't surprise me to find that the carb is defective too but it's not the filter or a bad fuel line. it doesn't act anything like that. it acts like a saw that is running too lean due to an air leak. actually i've been worried about it since the first day i had it because i could never get the idle low enuff to kill it. the lowest it would run is 2700rpm with the adjustment screw off the throttle lever. now it won't idle slowly enuff to fully disengage the clutch. anyway, i'm in the process of pressure checking it now. i have to make up the two plates, one with a hose barb. i really don't know why i'm bothering. my gut is telling me to leave it in the bed with the tailgate open in the walmart parking lot. but my chucking furiosity is driving me in another direction. as i said previously i don't think that this is a good work saw. i don't think it would be likely to make it thru a job without breaking something. anyone reading this, it's a waste of time and money.

anyway, looking at your excellent clutch tool, i decided if i made a tool with three dogs, like yours, only two dogs would be doing all the work. so, i came up with this. th dogs are 10mm allen screws. the handle is 3/16" thick, part of a hinge for a large gate. it has more the 12" of moment so getting the clutch loose was easy. (it was on backwards)


View attachment 349920

here's the pto-side seal. it looks like it may have been jammed in crooked. the rubber is tore up on one side, around 8:00 o:clock

View attachment 349921

Your clutch was backwards too? Wow.

I think you are on the right track with the air leak, as mine has never had an issue with idling down. It will putter along at quite a low rpm.

You know, it's a shame as they only need to pay a modest amount of attention at assembly for these to be fine. But then that is one reason why they are priced as they are. More evidence that these are chainsaw kits - though it would actually be better to just get a box full of parts.

Oh, and I like your clutch tool - I made a similar one for my Poulans.

 

[Chris-PA]

I was splitting some oak last evening and I brought the saw along for noodling some crotches and bucking up some smaller stuff. It is light enough to use for limbing and such - I'd prefer one of my smaller saws for that but it's nice when you've only brought one saw. The saw started and ran flawlessly, and I feel like I've got the bugs worked out of it now. I cannot tell any difference with the additional unplanned muffer mod, either in power or noise.

So I ordered a chain for the 25" bar that came with it - Oregon 75DP as I wanted semi chisel.

At this point the only thing I need to tweak is the length of the fuel and oil lines, so the pick-ups will sit in the bottom of the tank properly. They are sometimes getting stuck up by the caps.

 

[heyduke]

chris-

i pressure-tested my richmond saw today. i expected to see a problem with the pto side but it was on the flywheel side. it was leaking badly. i'm not posting fotos or vid yet. want to put it together in a coherent way. the seal was easy to remove, a loose fit in the bore. there was a significant amount of sawdust behind where is was failing. on the pto side there is work to do too. the seal is misaligned, sticking up perhaps .5mm on one side and down an equal amount 180 degrees opposite. i'll try to fix that. i recommend that you inspect both seals. i'm ordering a new seal and woodruff from partstree. either the woodruff was never installed or it transdimensionalized into an adjacent universe while i was moving the flywheel into the container for larger assemblies. i never saw it.

 

[Chris-PA]

chris-

i pressure-tested my richmond saw today. i expected to see a problem with the pto side but it was on the flywheel side. it was leaking badly. i'm not posting fotos or vid yet. want to put it together in a coherent way. the seal was easy to remove, a loose fit in the bore. there was a significant amount of sawdust behind where is was failing. on the pto side there is work to do too. the seal is misaligned, sticking up perhaps .5mm on one side and down an equal amount 180 degrees opposite. i'll try to fix that. i recommend that you inspect both seals. i'm ordering a new seal and woodruff from partstree. either the woodruff was never installed or it transdimensionalized into an adjacent universe while i was moving the flywheel into the container for larger assemblies. i never saw it.

Thanks for the head's up. This is cropped from the only image I took with the flywheel off, but I really can't tell much from it:

It's working nice and I don't really want to take it apart now, but I will have to make it a point to inspect it soon. The assembly errors seem to be fairly systematic. On the other hand, mine shows no symptoms of an air leak at all - yet.

 

[Thommo]

The baffle falling off inside the muffler must be a common problem. I have got the 72cc version and that baffle came loose after the 3rd tank of fuel. i drilled an extra hole in mine before i welded it back in with my mig. The only other problem i had with my saw was with the recoil starter that broke and the rivets in the chain wore quickly. It is pretty thirsty on fuel. I could only cut through a 40 inch gum tree 3 times and it was out of fuel.

 

[Chris-PA]

The baffle falling off inside the muffler must be a common problem. I have got the 72cc version and that baffle came loose after the 3rd tank of fuel. i drilled an extra hole in mine before i welded it back in with my mig. The only other problem i had with my saw was with the recoil starter that broke and the rivets in the chain wore quickly. It is pretty thirsty on fuel. I could only cut through a 40 inch gum tree 3 times and it was out of fuel.

How does the 72cc run? I would not think the weight would be much different, so that should be a very light 72cc saw.

I didn't think it really needed that outlet baffle as the main baffle is still there to separate the can into two chambers. I really didn't notice any difference without it, either in noise or performance.

I've noticed my 62cc is pretty thirsty too, but I have mostly smaller saws with narrow kerf bars so I don't really have much to compare it to. It didn't seem awful in that regard, but once the bugs are worked out (hopefully now) and the novelty is gone I'll be back to using the smaller saws unless I need it.

 

[heyduke]

Thanks for the head's up. This is cropped from the only image I took with the flywheel off, but I really can't tell much from it:
View attachment 350646
It's working nice and I don't really want to take it apart now, but I will have to make it a point to inspect it soon. The assembly errors seem to be fairly systematic. On the other hand, mine shows no symptoms of an air leak at all - yet.

yes, if it's working, don't mess with it. you'll know right away if you develop a leak. this one s leaking around the bore, not the shaft. i'm hoping that a new seal will be a tighter fit. but it could be that the 20mm bore was just cut to large.