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Hi Mark, The interactions of various metal's used in cylinder / piston piston ring combinations is an interesting topic. Certain combinations work very well, and it was found in the late first half of the last century, chrome faced rings extended life between engine overhauls substantially over...

Mark, If you can find a supplier who can match the OE spec, such as steel for thin rings, chrome plate for iron bores etc, that price or even more would be OK. I think you can be confident enthusiasts like me will appreciate they are getting a good product, knowing what it costs to make things...

Danarm filed several patents at around the same time, theirs is quite specific about coil springs, McCulloch cite rubber or material with high internal damping, which is quite different. Danarm was a UK patent, McCulloch a USA patent. So neither world wide in their effect...

This is very interesting! I thought Danarm held the first patents on vibration mounting, they certainly made claims, and proudly displayed their patent numbers on their products right back to the early '70s. Danarm used coil springs, 1-71- SS model probably the most prominent model, but the...

Nice fixture setup. Mass production now!

Great job! Good to see everyone having fun. Some time back I put up my effort on the PM700 mild port job on these pages, and all is well with that saw. My experience with iron bores is you need quite a bit more cylinder to piston clearance with iron sleeved engines compared to Ali bores, like...

Jethro, I set the timing to where I wanted it and scribed a line on the piston skirt, then pulled the crankshaft assembly out the block. Luckily I have a toolroom to hand so I quickly milled the material off the piston skirt to the line, but could have easily filed it if needed. A small chamfer...

So have a bit of run time on the hot rod project 700. Had both the tweaked and standard 700's running together, and picking up in turn cut on cut to get a feel for what the result was. To recap I have extended the intake timing to 140' of duration, tided up and blended the various steps in the...

I have a 555 700 850 and they all have the 44a SDC carb. Seems the 125's have a similar cube carb too. Clearly McCulloch's development team found this single carb good across a wide range of displacements. Naturally some sort of thought process has go into the number of step changes needed to...

Yes, Doing this sort of thing you need a pile of parts saws to play with. Also you have to be careful, as I get onto later. Today I ran up the PM 555 with the newly rebuilt carb. Massive improvement but still not perfect. Low screw out 1 1/2 turns and speed changes on tilting. I built this about...

Jethro, I am wary of doing much to these transfers for now. In my experience on other projects, its easy to make fuel consumption go crazy, which I reason is down to critical detail of direction as well as more general timing detail. As this is a first stab at the 700 - easy to revisit...

Jethro, You pick up on exactly on the point. I certainly am not in the cutting business, but get sufficient trigger time on my collection to get to know their individual traits. The 10-10S / 555 / 57 cc jobs as you say stock is impressive, but I have already done to a 555, what I intend to with...

Found bit of time to play with the Pro Mac 700 "hotrod" project. If you recall this is a duplicate saw to a very nice PM 700 I already have. The PM 700 in my experience is all about torque. I don't do much felling, but when I do, the 700 is the weapon of choice, its easy to use and forgiving to...

I used something similar to engineers scribe with the sharp point reduced to a ~ 0.020" rad. I did try to photo it but focus was poor. Carb back together now, and on the saw. Bit late to start it up - sensitive neighbours - well neighbours some houses away who seem to differ about the wonderful...

Core plug - local lingo for welch plug. I just use the ones in the kit, minimum loctite applied with a pin to the recess, and gently expanded with a suitable flat punch. I did turn one up on the lathe once for McCulloch flat back. was about 1" dia and it worked fine. I suppose for the small ones...

Pleased to report a successful conquest of this hole problem! With a good tool I was able to cut some tight sharp wads out of a spare diaphram like this. Again with another good blunt tool the job was done and the disc implanted. The valve checks well so all remains is to fit the core plugs...

Come on guys - surely fitting an object through a tight orifice is a worthy challenge! Just knocked up a tool today to cut the diaphragm material, but carelessly left it at work. So it will be tomorrow at the earliest I get the chance to perform! Roland.

Awesome! beat my ramble a moment ago! Cheers. Roland

That is the monkey! The repair kit I have is the full general kit, so I need to find one of the specific 86-523 jobs, seems scarce in the UK- at a glance anyway. I confess to not researching hard for supply of separate and specific kit. I had to order the SDC repair sets from abroad. Would you...

Right, finally got this stripped down. Been right up to my neck in it with work, firewood and family along with chairing a sports club in this covid 19 mess. So to recap - mcculloch promac 555 with big flat spot. Carb is a sdc 44a and this has a check valve under the hi speed nozzle which acts...