How to make your 7900 or 681 NON rev-limited

[Andyshine77]

Stock vs stock the 7900 and 681 are close, but the 681 normally wins.

Jason if your stock 681 beats a well ported 7900 I want it! lol. Honestly it sounds like the two ported saws you have ran faster stock, than they do ported. This is not uncommon with the 7900/681 IMHO. The early 7900's that DD did were also slower than stock! Than KD, DN and EHP made a few and changed that. You, I, EC and others know a new Husky piston will make things even better!!

A short bar will always cut slower than a long bar if the nose is berried in the wood, and is in a knot. They're only a few ported 7900/681's that I have ran, that run well. This reminds me of the LT1 engines. A few wrong things will make it run slower and a few right things will make it run faster.

Jason your 681 ran well when I ran it, but it was nothing special. I felt the 441 and 372 on hand were faster, but I didn't think a stock 681 would beat it. I'll go out on a limb here and say that the power band was moved up, but not necessarily increased overall, and some of this may be in part my fault as I suggested Brad moved the transfers up a bit.

Nevertheless I didn't see a stock 681 beating it in the right hands, but than again I've been a retard most of my life. With all this said, I try not to step outside of my understanding of mechanical engineering and knowledge, and for me that's pretty easy to do lol.

I try and call it as I see it, and your 681 was nothing special, and a learning tool for Brad IMHO, and I hope you and him worked things out if they needed to be.

Andre.

 

[gink595]

Andy, believe it ot not mine is still running stock piston. What Husky piston works?

 

[WoodChuck'r]

Stock vs stock the 7900 and 681 are close, but the 681 normally wins.

Jason if your stock 681 beats a well ported 7900 I want it! lol. Honestly it sounds like the two ported saws you have ran faster stock, than they do ported. This is not uncommon with the 7900/681 IMHO. The early 7900's that DD did were also slower than stock! Than KD, DN and EHP made a few and changed that. You, I, EC and others know a new Husky piston will make things even better!!

A short bar will always cut slower than a long bar if the nose is berried in the wood, and is in a knot. They're only a few ported 7900/681's that I have ran, that run well. This reminds me of the LT1 engines. A few wrong things will make it run slower and a few right things will make it run faster.

Jason your 681 ran well when I ran it, but it was nothing special. I felt the 441 and 372 on hand were faster, but I didn't think a stock 681 would beat it. I'll go out on a limb here and say that the power band was moved up, but not necessarily increased overall, and some of this may be in part my fault as I suggested Brad moved the transfers up a bit.

Nevertheless I didn't see a stock 681 beating it in the right hands, but than again I've been a retard most of my life. With all this said, I try not to step outside of my understanding of mechanical engineering and knowledge, and for me that's pretty easy to do lol.

I try and call it as I see it, and your 681 was nothing special, and a learning tool for Brad IMHO, and I hope you and him worked things out if they needed to be.

Andre.

I hear what you're saying. The powerband moving up makes some sense. The saw holds it's RPMs better in the wood now that it's converted back to stock though. It doesn't seem to run as lean as it used to, but somehow I seem to think that's still being starved a bit for fuel. Maybe that's it's change in the timing, I don't really know as I don't understand these machines the way a good builder does.

Brad suggested that the flywheel has slipped on the saw - but I know it hasn't. The flywheel is in the exact same spot it was in the day it left his home. He also said that he can not help what happens to a saw after it leave his posession, which is all well and true - but I swear to everyone here that the only thing that has been done to that saw was have the original P&C and muffler replaced with brand new stock parts. The flywheel or timing and not been touched one iota.

Overall Andre, you're correct. The 681 when I got it wasn't anything special. Although at the time, I thought it was. It was the first ported saw I ever owned. It was a pretty exciting day to get my hands on that saw and run it for the first time. I kinda thought I had the cream of the crop when it came to that 681. Everyone read my cheerleading thread back in January about how kick a$$ I thought the saw was. Kinda wished I hadn't spoke for the saw so vividly, I gave myself the reputation of being a cheerleader of a saw that everyone literally laughed at in the background. It was pretty tough understanding and accepting the fact that the saw was basically a dud.

And to elaborate a little more on the comparison back in April - it was as fair as it could possibly be. Both saws ran the same bar, same chain, and cut in the same cant of white pine with no knots. The owner of the saw even insisted that I check his saw out to make sure he was running the same air filter, and that his saw was fully a stock saw, it was. I was running 93 octane non ethanol with R50 @ 32:1. The stock 681 I compared mine to had 87 octane with dino oil @ 40:1 or 50:1 (I don't fully remember the fuel mix ratio he was using). The saw was run by 3 operators, one of them being myself. The stock 681 was 2-5 tenths faster each and every time. The times were consistent for both saws. I remember being able to push a little harder on the stock 681 over mine. I'll never forget it. This was no setup to make Brad or the saw look bad. It was to put to test the saw that I thought was so great. I couldn't believe what had happened after I saw that stock 681 beat mine. I honestly didn't want to believe it - but the proof was right there in front of me.

And just so everyone knows - I'm doing this to argue with Brad or fight with him. I have no intensions of doing so. None of this is new - all of my findings occurred in back in April, six months ago. Brad knew about the comparison of both saws the evening I got home. I didn't want rumors to get spread or anything ugly to come of all of this, so I contacted Brad, the original owner and builder of the saw to let him know what I had found. We had some discussions back and forth a little and I made the decision to buy a new stock P&C and new stock muffler. He offered to help compensate for the cost of the new P&C and I told him I did not want any money. When I return him his cylinder I'm sure he'll send me compensation - I wish he wouldn't as I don't want anything for it, but it's his choice and that's his business. We have not exchanged funds or the original P&C yet because of the decomp valve. I want to have it on my new stock cylinder. That is how I handled it back in April. I wasn't going to low ball him with a negative attitude and sell the cylinder to someone else without him knowing the things I had found out with the saw. Things like this should always be brought to the original owner and or builder so things can work out properly.

 

[FATGUY]

Anyone got a nice HD 6401 for sale

perhaps not for sale, but maybe we can use this one.....

I even know a monkey that can turn 1mm from the base to compensate for the shorter Dolmar stroke.....

 

[mdavlee]

That would be a good sleeper saw for sure.

I think a 272 piston will fit.

 

[solo]

This saw would look better if you could get a bit of Solo red on it to go with the other colors. For real I like the look.

perhaps not for sale, but maybe we can use this one.....

I even know a monkey that can turn 1mm from the base to compensate for the shorter Dolmar stroke.....

 

[wigglesworth]

So the stock 681 outran the ported 681 and now the ported 681 is back to stock?

 

[WoodChuck'r]

So the stock 681 outran the ported 681 and now the ported 681 is back to stock?

Yep. You got it.

 

[tjbier]

Anyone got a nice HD 6401 for sale

I would like to put that 681 ported on this fella I recently picked up.:monkey:

 

[blsnelling]

Seriously, if anyone has a clean HD 6401 they'd want to sell, I'd be interested in buying it to check out this P&C.

 

[Andyshine77]

Overall Andre, you're correct. The 681 when I got it wasn't anything special. Although at the time, I thought it was. It was the first ported saw I ever owned. It was a pretty exciting day to get my hands on that saw and run it for the first time. I kinda thought I had the cream of the crop when it came to that 681. Everyone read my cheerleading thread back in January about how kick a$$ I thought the saw was. Kinda wished I hadn't spoke for the saw so vividly, I gave myself the reputation of being a cheerleader of a saw that everyone literally laughed at in the background. It was pretty tough understanding and accepting the fact that the saw was basically a dud.

Jason I don't know who these guys laughing are but they don't sound like nice guys to me. They should have helped you not laugh at you. I've been to, and have heard of GTG's where guys were playing games to make others look bad. I'm not saying this is so with your saw, but this does happen.

Like I said stock vs stock the 681 is stronger than the 7900 but I don't see a stock 681 beating a good running ported 7900.

In the end it sounds like everything turned fine.

 

[WoodChuck'r]

Jason I don't know who these guys laughing are but they don't sound like nice guys to me. They should have helped you not laugh at you. I've been to, and have heard of GTG's where guys were playing games to make others look bad. I'm not saying this is so with your saw, but this does happen.

Like I said stock vs stock the 681 is stronger than the 7900 but I don't see a stock 681 beating a good running ported 7900.

In the end it sounds like everything turned fine.

Overall yes, things turned out just fine. It wasn't as big of an ordeal that I could have made it out to be. I'm just not an a$$ like that.

I wasn't being laughed at personally, but the saw was. Most thought the saw was an absolute joke. That was something I found out later on too. It was a rough entry in the early beginning of finding out that the saw was not what I thought I had, but live and learn. This is all a learning experience for me - I've learned quite a few things since then. I just couldn't believe that the saw was slower than a stock saw. It was suggested numerous times that I run it with a stock 681. That time finally came and the proof was in the pudding. Nothing was tampered with or skewed. That stock saw was faster. Even both the ported 681 and stock 681 were about 1-1.5 seconds faster than my 7900. You should have seen the look on my face that day.....

Shows how ignorant to ported saws I really was. I had no clue what I had but I ranted and raved about how good it was.

And once again about the 681 beating my ported 7900 - I have no clue how that's even possible. But it cuts faster and out torques it too.

Those 681's are un-freakin' real when it comes to the amount of power they have. They're unbelievably impressive. I can only imagine what a damn good woods port will do to one.

 

[Andyshine77]

Andy, believe it ot not mine is still running stock piston. What Husky piston works?

I honestly believe you 100% I've ran a few of EC's saws, and you're an unbelievable welder. I have no clue as to which husky piston would work.

 

[Andyshine77]

Overall yes, things turned out just fine. It wasn't as big of an ordeal that I could have made it out to be. I'm just not an a$$ like that.

I wasn't being laughed at personally, but the saw was. Most thought the saw was an absolute joke. That was something I found out later on too. It was a rough entry in the early beginning of finding out that the saw was not what I thought I had, but live and learn. This is all a learning experience for me - I've learned quite a few things since then. I just couldn't believe that the saw was slower than a stock saw. It was suggested numerous times that I run it with a stock 681. That time finally came and the proof was in the pudding. Nothing was tampered with or skewed. That stock saw was faster. Even both the ported 681 and stock 681 were about 1-1.5 seconds faster than my 7900. You should have seen the look on my face that day.....

Shows how ignorant to ported saws I really was. I had no clue what I had but I ranted and raved about how good it was.

And once again about the 681 beating my ported 7900 - I have no clue how that's even possible. But it cuts faster and out torques it too.

Those 681's are un-freakin' real when it comes to the amount of power they have. They're unbelievably impressive. I can only imagine what a damn good woods port will do to one.

Glad to hear it's all good lol.

The thing with the 681 and 7900 is the fact they are different than most saws and they have limitations from a woods ported stand point. They cane be made to run, but one wrong move and they will run slower. If I had to guess the pop up piston on your 7900 likely made it slower, at least that's what I've seen happen a time or two. The only saw I've ran that gained anything from a pop up IMHO is MCW's kita 7900, and even than it lost some rpm's but it did gain a lot of torque, and that's what he wanted.

 

[willsaw4beer]

Wow, after reading all this I sure am glad I put my focus into sharpening chains instead of trying to learn how to port.

 

[WoodChuck'r]

They should have helped you not laugh at you.

I was helped - especially by one person in particular. Made things easier to understand. I've seen quite a bit by even going to the few races I was at this summer. Most woods ported saws wouldn't stand a chance to some of the saws I've seen out there. And the other saws that really run are still woods ports, they're just damn good ones. It wasn't just me with my 681 that had a slow woods saw, trust me.

We newcomers to ported saws have a lot that we don't understand. But that's okay, we've all gotta start somewhere. I don;t know if I'll ever stop being fascinated by what these machines can do.

 

[PLAYINWOOD]

sometimes a good "gtg" saw isn't worth a hoot in the woodpile, regardless of what the builder tells you...

I refuse to have some of these goodies that are now installed in so called woodport saws in my saws that are bred to work.

I find no solace in beating someone at a gtg with a saw that aint worth a pinch of coon **** in my money woodpile.

Some builders will travel miles to prove others suck with speed but sometimes speed is the icing
The cake is making me 5 grand a year for 10 years...

The question is ...where does a work saw stop...and mild race (heat)begin?

 

[AUSSIE1]

sometimes a good "gtg" saw isn't worth a hoot in the woodpile, regardless of what the builder tells you...

I refuse to have some of these goodies that are now installed in so called woodport saws in my saws that are bred to work.

I find no solace in beating someone at a gtg with a saw that aint worth a pinch of coon **** in my money woodpile.

Some builders will travel miles to prove others suck with speed but sometimes speed is the icing
The cake is making me 5 grand a year for 10 years...

The question is ...where does a work saw stop...and mild race (heat)begin?

You make some good points.
But anything goes at a GTG I suppose. It's like you say though, is it a true work saw.
Can they run for long periods in large hardwood?
With that said, look at it this way. A saw ported properly with the parts at hand by someone experiened can produce some fast saws. Ginks 7900 comes to mind!
What are you refering to when you say "goodies"?

 

[gink595]

I honestly believe you 100% I've ran a few of EC's saws, and you're an unbelievable welder. I have no clue as to which husky piston would work.

I've welded some pistons but not in that one! I had the oppurtunity to suit the 7900 with a 32" bar last weekend and cut some hard maple, it put my 880 to shame, it cut faster and had more balls. The bar was buried for the most part of several logs, sometimes I had to cut from the other side to finish it. That was the first time I've really had a chance to use it in big wood and I couldn't have been more pleased with it.

 

[tdi-rick]

[snip]
You, I, EC and others know a new Husky piston will make things even better!!

[snip]
Andre.

Andy, believe it ot not mine is still running stock piston. What Husky piston works?

It's been long rumoured but I can't recall a Husky piston actually being able to be used.

I'm pretty sure (but happy to be wrong) that the pin to crown height was wrong (and not easily corrected) or the pin diameter was wrong on any that were suggested as an alternative.

I do know we had a big discussion on this on RS a few years back and IIRC no one was able to come up with a viable alternative.

A rod change may change things, but the ol memory aint what it use to be :monkey: