Porting a Chinese G621 Clone

[Chris-PA]

very nice write up. Thanks for sharing.

I'm still trying to figure out if this was made by the same outfit as the Earthquakes. I think it is - I know they make a version of it under the "Topsun" name with different styling (and a decomp valve), but there's no way to be sure.

 

[Wagnerwerks]

The guys like us with the messiest desks are usually the ones who get the most work done.

I resemble that comment.

 

[sachsmo]

With the money an engineer makes, and the time spent lining up filter covers on this junk, "porting," the junk and sharing the tale he could buy a MS261 with M-Tronic and a broom to get that crap out of the bed of his truck. It takes all kinds and what WHW is doing is interesting. Why chain some Chinese kid to a machine that clones crap when there is wood to cut? We still never saw the ported strato intact saws run of Chris-PA's doing to my knowledge.

So,,

Chris is an Engineer?

No wonder he seems to have a hard on for me, no doubt read some o' me posts dogging his trade eh?

I be in the trades, we deal with Engineers daily, and usually have to 'field fit' their boof-ups.

Either that or scab sumthin together to keep production running while they over analize the problem. Then they spend a week drawing sumthin up send material out to be water jetted, send it to the machine shop, out to the welder,back to the machine shop, finally back to the plant. Then let some poor SOB 'field fit it'.

YUP, we in the trades have little love for 'Engineers', (only the ones who pilot trains eh?)

 

[Chris-PA]

So,,

Chris is an Engineer?

No wonder he seems to have a hard on for me, no doubt read some o' me posts dogging his trade eh?

I be in the trades, we deal with Engineers daily, and usually have to 'field fit' their boof-ups.

Either that or scab sumthin together to keep production running while they over analize the problem. Then they spend a week drawing sumthin up send material out to be water jetted, send it to the machine shop, out to the welder,back to the machine shop, finally back to the plant. Then let some poor SOB 'field fit it'.

YUP, we in the trades have little love for 'Engineers', (only the ones who pilot trains eh?)

Sounds like you need some better engineers. Our production floor is 20' from my office, and there is no door on my office. There are folks on that floor I've worked with for 25 years, and we were out drinking together back before families and responsibilities and stuff. If it doesn't work they know where to find me and they aren't shy either.

Besides, I know our stuff goes together properly because I built the first ones myself, and designed the manufacturing tools and fixtures. If it doesn't work then something has changed or someone is doing something wrong. The biggest PITA is when some genius keeps struggling with something that obviously isn't working right and/or tries to re-engineer it themselves. That usually leads to recalls.

 

[sachsmo]

Guess we just get the 'posers' (and their drinking buddys)

Actually we only have 2 degreed engineers (out of 7) and one has a degree in 'Process Engineering'

Nice Anology:

Maintenance Man says,
"IF it ain't broke don't fix it"

Engineer says,
"If it ain't broke we haven't added enough improvements"

 

[diggers_dad]

With the money an engineer makes, and the time spent lining up filter covers on this junk, "porting," the junk and sharing the tale he could buy a MS261 with M-Tronic and a broom to get that crap out of the bed of his truck. It takes all kinds and what WHW is doing is interesting. Why chain some Chinese kid to a machine that clones crap when there is wood to cut? We still never saw the ported strato intact saws run of Chris-PA's doing to my knowledge.

Chris,

That's why.

dd

 

[anlrolfe]

Non-compliant chainsaw test

 

[Chris-PA]

Chris,

That's why.

dd

Yup - but there's something else going on with this one. The game doesn't interest me.

 

[Franny K]

Does it have an epa compliance hour rating? How about noise and vibration rating?

 

[Chris-PA]

Non-compliant chainsaw test

Yeah that bit of marketing fluff has been around a while. The saw they tested is not a copy of any Stihl, it is clearly a RedMax G5000 clone. I suspect the original G5000 would have performed the same. Does that make it a bad saw?

Do the tests represent what you would do with a saw? If those kinds of forces were placed on the saw, what would happen to the operator? Did the added strength needed to pass those tests increase the price or weight, and would you make that tradeoff if it did?

 

[Chris-PA]

Does it have an epa compliance hour rating? How about noise and vibration rating?

This thing has no strato or AT technology and has no EPA tag - it's clearly not really permitted. On the other hand, it has quad transfers and if they reduced the volume (increased the velocity), tweaked the port timing, set it lean with special mixture srews and stuffed a cat on it then it would likely pass. This is no different than what is done with many big name saws.

It has a 110dB label and a CE sticker - as to whether either of those is legit I don't know.

 

[rmh3481]

Good thread, Chris. Take a look at an HDA-63, standard H/L w/o caps, 16.7mm venturi and an integral choke.
http://wem.walbro.com/walbro/product2.asp?partnum=HDA-63-1&Series=HDA

 

[RedneckChainsawRepair]

So are they really 62cc? Did you check bore and stroke? If so what are they?

Reason I ask they have the same looking saw for sale listed as 52cc 58cc 62cc with different bar lengths. 62cc listed $150

 

[Chris-PA]

I dressed the chain today - that was a PITA because they had ground it too deep and that kept pulling the file too low, plus they overheated it and left me a bit of crust to break through. It's not perfect but pretty decent now (the filing anyway). Then I took it up and did some noodling, as some large oak rounds was all that was sticking out of the snow to mess with. I had thought the light saw with the 24" bar would be awkward, but it wasn't while cutting. It rand quite well and I dialed in the tuning. Seemed pretty routine, 4-stroking lightly when I lift. Muffler is pretty loud as-is.

The chain stretched really fast, and I noticed it had stopped oiling. Plus my shoulder isn't really up to using a saw for long yet, especially after I foolishly tried a drop start, so I came back down to the barn to figure it out. It turned out that the inlet line where it goes into the pump had split. For now I just pulled more line through and cut off the last 1/2", but that line will need replacing. I could get to it with a forceps once I removed the brake cover - it is behind the end of the brake band. It oils fine again.


Then it turned out the oil fill cap was leaking. The gasket they used was too small a diameter to seal against the case, so I made a new one out of some rubber stock I noticed that that fuel filler cap from my Ryobi will fit the oil fill cap on this perfectly and the gasket will seal.

 

[Chris-PA]

So are they really 62cc? Did you check bore and stroke? If so what are they?

Reason I ask they have the same looking saw for sale listed as 52cc 58cc 62cc with different bar lengths. 62cc listed $150

Yes, this matches the stock bore & stroke of the G621. There are also several versions of the "mid-sized" RedMax saw that they sell with bored and stroked engines, including some up to 62cc. These are different engine & saw designs. Usually they are 0.325" chain. As I said up thread, I shied away from those because the carb was small and could not easily be upgraded.

Actually they sell 72cc versions of this saw in OZ.

 

[Chris-PA]

Good thread, Chris. Take a look at an HDA-63, standard H/L w/o caps, 16.7mm venturi and an integral choke.
http://wem.walbro.com/walbro/product2.asp?partnum=HDA-63-1&Series=HDA

Cool - thanks!

 

[Chris-PA]

So at this point I think this saw should be thought of as a chainsaw kit. It's based on a good design - the G621 is pretty neat as far as I'm concerned - but the assembly quality is not good enough as-is. I think a pretty complete tear down and proper reassembly should be considered a requirement (but that is what I bought it for). Little stuff needs fixing & correcting - not a problem for someone who knows how to work on it but enough to make it a big mistake for the casual user.

It was really pretty similar to the Earthquake: The castings were not terrible, with the cracked cooling fins on top of the jug being the worst, although that doesn't not really matter. Once the flashing was cleaned up all the plastic parts fit fine. The machining was not pretty but was functional.

Unlike the Earthquake, which meets emissions regs, the stock porting and muffler are quite nice as-is. The squish is the biggest problem, quite fixable if I felt like turning an insert for it. Then again, while it has a boss cast on the cylinder it has no decomp valve, so maybe keeping it at 0.035" squish is good unless I add one.

It did come with a spike - I only like them for falling, but this saw is light enough for that so I put it on:


Oh yeah - I took the bow out of one half of the air filter by heating it with a heat gun, and then sealed the two halves together with Yamabond. It should be serviceable.

 

[Terry Syd]

Dang spill the beans on someone for engineer is like telling them the poor bastard was a lawyer.

Hmm, I was a Barrister (trial attorney) for 20 years. I have also modded a Chinese chainsaw successfully. I don't know, maybe engineers and lawyers like to relax with an intellectual challenge outside of the humdrum work day. It is more fun than playing Chess, and there is a giggle factor when some bloke with a 'name brand' saw gets his azz handed to him from some Chinese POS.

 

[Terry Syd]

The only Chinese saw I've built was a 365 clone. It is now a 77cc work horse I use for bucking. Its done a heap of work, some minor problems with the tank vent and a broken clutch spring, but otherwise very reliable.

I was at a dinner and I got into a discussion about chainsaws with the local mill operator. He has a genuine 365. When I said my Chinese saw would beat his, his reply was "No way!". That led to a race over at his mill. He and his brother ran both the saws and were shocked how the Chinese saw just flat out left the stock Husky way behind.

I felt so bad about their humiliation that I rebuilt their saw to the same specs. Now they have a giggle factor when some bloke shows up with a Stihl.

 

[Chris-PA]

I was drawing out the diagram of the port timing and thought I'd stick it in here: