Finally Going To Do One, Just To See

I am sure you have all experienced the situation when the engine bogs in the cut. I think of this as when the engine can no longer produce enough torque to overcome the resistance of the wood and cannot continue pulling the chain through the wood and you have to lift off.

HP=(RPM * T) / 5252 where 'T' is torque sort of like the calc for watts, W=V*A so you can have 1 volt and 10 amps or 10 volts and 1 amp both produce 10 watts but the 10 amps version will do more work.

 

I just wonder if the solo 665 jug is as nice as this oem 65cc jug.

Man I love the quad port 65cc 71cc cylinders on my poulans.

 

Hedge I consider a 125 torque monster. JMO though.

 

Pretty jug Kevin!

 

I rebuilt a Jred 820 for a good customer and that was quite the saw. Did not turn a lot of revs but all you had to do was set it on the wood and it would chug right trough. It would start pulling the chain right off idle and continue pulling right up through the rev range.

 

I haven't found anything yet that caused my 125 to bog down,including 36"+ White Oak.The Husqvarna 2100CD & 288XP does a little bit in hard stuff over 30" however,especially when ripping freehand or using the Alaskan mill..

 

This from Randy on another thread, thought you guys would like it! OBTW, Randy=Mastermind.

Now you know why I want to build one.

 

From several of Randy's comments one could draw some useful information. His measurements indicated that the port timing was the same between the 7900 and 681 which would add considerable weight to Hedgerow's comment in post #28 and Randy's comment above

that at least some of the torque must be coming from the increased stroke and increased case volume Hedgerow pointed out. We are still trying to figure out how Solo compensated for the 1mm increase in stroke without using a spacer. They could have increased the thckness of the cylinder base, the actual bore in the jug is deeper, or perhaps they did something to the piston. At this point we do not know.

 

Just going by the BB7900 aftermarket cylinder kit. Goes on 7900 without anything special at base bolt on.
681 uses 1.5mm spacer to work on 681. That tell me the extra must be on the cylinder. Just my WAG.

 

Great oservation Kevin, tell Randy!