That saw looks awesome 2broke!
McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
Help Support Arborist Forum:
Nope. Probably don't see many high end lightweight bars returned 'cause the buyer didn't know their mounting pattern, tho!
There are great deals to be had on all types of returned Amazon products. Some obviously hold greater risk than others. That's also why lots of Amazon products are ridiculously marked up..., even well above MSRP on the manufacturer's own web sites. That's counting on first click / impulse buying with Prime and people do it all day long.
ML12
ArboristSite Guru
@PogoInTheWoods
Here are the photos of my 7-10 as promised!
The bottom end was evidently full of water for a while, so it needs a good cleaning, and seal and bearings, and a muffler, and clutch cover and and and. I may just wait until a suitable 10-10 comes along then put the 70cc motor into it as it'd probably be cheaper than sourcing the individual parts here in Canada. The top ring was stuck, and it still made excellent compression.
The piston has an odd scuff (flat spot) on the intake side skirt, but there are no marks in the bore plating and the piston is worn smoothly.
Here are the photos of my 7-10 as promised!
The bottom end was evidently full of water for a while, so it needs a good cleaning, and seal and bearings, and a muffler, and clutch cover and and and. I may just wait until a suitable 10-10 comes along then put the 70cc motor into it as it'd probably be cheaper than sourcing the individual parts here in Canada. The top ring was stuck, and it still made excellent compression.
The piston has an odd scuff (flat spot) on the intake side skirt, but there are no marks in the bore plating and the piston is worn smoothly.
Thanks. Will add them to the "70cc's of Insanity" folder accordingly. LOL
And....., turns out Bob J. didn't have a 69030 full skirt thick ringed piston for my 7-10 after all even though he showed several in his inventory. The other thick ringed options left for the iron bore are a windowed 85239 with the thick 85241 rings or the 69412 full skirt piston (with the 85239 rings) that I originally bought. That'll require swapping the connecting rod, but I broke down and bought the pin removal/installation tool from Duke just in case. Scavenging a longer rod with smaller pin end from a 10-10 carcass may be the way I'll go with this at the outset if the squish is acceptable. (Still wonder a little about the significance of the 0.010" squish difference between the two piston/rod combinations Mark came up with in his calculations a few pages back.)
On the other hand, I exchanged a few PM's with (Steve) Mac6-10 last week on the whole thing and he is indeed running thin ringed 85239 windowed pistons in both a CP70 and a 6-10A having the three fingered transfers without issue. Sure wish I'd have known that sooner or run across it posted somewhere before getting so carried away. So much for all my theorizing and all that wasted time pissin' up a rope for not only myself, but for everyone here who put up with it. You guys sure are a remarkably patient lot!
So back together it goes knowing it will likely have the original idling problem still needing figured out. I did order a new set of the thin 89732 rings for the piston Kevin put in it and Bob threw in another thin ringed 85239 that he said 'needed some help' as an example of some of the stuff he pulls out of his parts buyouts from different places. And I do plan to check cylinder/piston clearance before buttoning it back up as I don't recall if that has ever been covered in all this. Seems like excessive skirt slop could certainly play a role in the idling even with good compression otherwise. And we are talking about an old-ass saw with an iron bore. If the bore turns out to be crazy out of spec, well, the search will be on for another cylinder unless boring is less expensive than I think it'll be. (Bob does have some of those pistons, fwiw.)
But I digress..., lol.
Bob J. says some bubble gum and a cheap cigar will find the problem. Block off the exhaust, plug the carb intake with a wad o' gum and a drinking straw through it, fire up that cigar and start blowing smoke. Absolutely elegant in its simplicity, isn't it?
And....., turns out Bob J. didn't have a 69030 full skirt thick ringed piston for my 7-10 after all even though he showed several in his inventory. The other thick ringed options left for the iron bore are a windowed 85239 with the thick 85241 rings or the 69412 full skirt piston (with the 85239 rings) that I originally bought. That'll require swapping the connecting rod, but I broke down and bought the pin removal/installation tool from Duke just in case. Scavenging a longer rod with smaller pin end from a 10-10 carcass may be the way I'll go with this at the outset if the squish is acceptable. (Still wonder a little about the significance of the 0.010" squish difference between the two piston/rod combinations Mark came up with in his calculations a few pages back.)
On the other hand, I exchanged a few PM's with (Steve) Mac6-10 last week on the whole thing and he is indeed running thin ringed 85239 windowed pistons in both a CP70 and a 6-10A having the three fingered transfers without issue. Sure wish I'd have known that sooner or run across it posted somewhere before getting so carried away. So much for all my theorizing and all that wasted time pissin' up a rope for not only myself, but for everyone here who put up with it. You guys sure are a remarkably patient lot!
So back together it goes knowing it will likely have the original idling problem still needing figured out. I did order a new set of the thin 89732 rings for the piston Kevin put in it and Bob threw in another thin ringed 85239 that he said 'needed some help' as an example of some of the stuff he pulls out of his parts buyouts from different places. And I do plan to check cylinder/piston clearance before buttoning it back up as I don't recall if that has ever been covered in all this. Seems like excessive skirt slop could certainly play a role in the idling even with good compression otherwise. And we are talking about an old-ass saw with an iron bore. If the bore turns out to be crazy out of spec, well, the search will be on for another cylinder unless boring is less expensive than I think it'll be. (Bob does have some of those pistons, fwiw.)
But I digress..., lol.
Bob J. says some bubble gum and a cheap cigar will find the problem. Block off the exhaust, plug the carb intake with a wad o' gum and a drinking straw through it, fire up that cigar and start blowing smoke. Absolutely elegant in its simplicity, isn't it?
I see ML12s 7-10 has the later port design like Vinnys SP70 and Tim's 7-10s.
So the whole time its been something else Poge? That piston falling in like that is a worry do ya think the bore is just very warn. if the skirt isn't sealing off those ports good enough it could play havoc. Can the oversized pistons still be found? Is there a company nearby who could bore it?
Interesting idea with the cigar
So the whole time its been something else Poge? That piston falling in like that is a worry do ya think the bore is just very warn. if the skirt isn't sealing off those ports good enough it could play havoc. Can the oversized pistons still be found? Is there a company nearby who could bore it?
Interesting idea with the cigar
That would seem to be the case considering Mac 6-10's experience with the windowed pistons in his CP70 and 6-10A three fingered cylinders.
Will check the skirt clearance when I have some time. Don't have the best method at hand (feeler gauges), but I'm beginning to get a funny feeling about what I may find.
I have no idea what's involved in boring the cylinder or where I'd get it done. There's a sled and dirt bike shop up the road that may be of some help there. Don't know how much (or if any) machine work they do. Bob J. claims to have some 69031 / 0.020 over-sized pistons and Mark appears to have at least 1. Rings may be another story altogether.
Now to find some renewed enthusiasm for getting back at this thing.
Awesome pics
For the right machine shop it should be a very simple job to bore that out. The trouble is that kind of thing has become a thing of the past. I got a old victa mower bored and the old boy (now retired) was puzzled why i wanted it done it took him 3 hours and he charged 90nz as he felt that was fair. Yes by the time I got a piston in it I was up at the 160nz mark for an engine I find at the dump most times i look. But i wanted to do it i wanted the original block on it and it was a great experience he tought me heaps in the process and I ended up taking a 4age Toyota engine there and blew 3 grand on that haha. He was a gruff old bugger with a cigarette lit in his gob at all times. When I brought the engine in we had pulled apart the head and he gave me a thick ear (literally) for getting the valve shims muddled up lol
I'm sure if it came to it and that's the way you end up going you could find someone on AS to do it who has the right gear for a fair price.
I'd be interested to know which cylinder is in Mark's 7-10 that could flog the 700 had in it. It seems we have atleast three different port style cylinders. Think his was the older 1 with the single label filter lid and a pop up dsp. Tim's with the bridged transfer has the two label air box lid I wonder if that was a change point the later labels his also has presence levers perhaps that's the change.
I'm just toying with the idea of a quick way to have a good guess at what cylinder it might have. There was something about the coil mounts too
Oh and keep at it Poge it brings us great enjoyment seeing this unfold and learning along the way. Filling our heads with more or less useless information for anyone but the hardest of Mac nuts lol
We are very excited to hear news about it and you may hear a woohoo from me if you point a good ear to the south when you get it running. And figure out what **** it was
We are very excited to hear news about it and you may hear a woohoo from me if you point a good ear to the south when you get it running. And figure out what **** it was
I just had another peek in my two label 7-10 and it's a bridged transfer same as ML12. My single label 7-10s are both bridge less transfer
I just slid a 0.007 feeler gauge between the piston and cylinder. That's the extreme for a kart engine. Saws are 0.005. I'm tempted to buy a cheap HF set of telescopic gauges to gain a little more accuracy, but I'm pretty sure the results would only be worse.
Boring cylinders is obviously common. Boring blind (no removable head) cylinders for small 2-stroke engines isn't. More of a specialty..., and priced accordingly.
Boring cylinders is obviously common. Boring blind (no removable head) cylinders for small 2-stroke engines isn't. More of a specialty..., and priced accordingly.
Ok so when you said the rings were very warn was that just from a gap measurement? Or they way they dropped straight in on the piston? Which seemed very suspect.
Yeah the boring thing that's why I was wondering about a saw guy who would be setup for it already
Yeah the boring thing that's why I was wondering about a saw guy who would be setup for it already
Both. The old ring on the left is 1.82mm wide. The new one on the right is 2.10mm wide. (I presume you meant dropped straight in on the cylinder in the little vid?)
Yeah thats what I meant normally it's a battle people even ask how to get them in.
Hmmm so these oversize pistons are they confirmed to be without rings?
Now another thought isn't cast iron softer than chrome?
Some telescopic gouges would also show it to be round or oval too
New pistons generally come with the bearings and rings, I am 99% sure the ones I have in the attic include bearings and rings.
AWOL has/had a Sunnen hone and was able to hone a 2-10 cylinder for me to fit an oversize piston so it may not actually require a boring set up if you can find someone with a suitable hone.
Mark
AWOL has/had a Sunnen hone and was able to hone a 2-10 cylinder for me to fit an oversize piston so it may not actually require a boring set up if you can find someone with a suitable hone.
Mark
Ah well that sounds promising
https://www.m-and-d.com/MAC-M69030.htmlThey may not have it either - I've had a few items I've ordered from them and then get an email a couple weeks saying they're going to refund me because they're out.
Thanks for the info.
I'm familiar with them and they're only a 45 minute drive away. I would only buy from them if they had it on the shelf as I've heard their lead times are horrible. And as you say, you can wait two weeks before finding out they can't get the part anyway. And their 69030 has been replaced by the thick ring 85239 which is quite a bit more..., around $60 I believe. I passed on an 85239 from Bob for that reason (among others).
I'm familiar with them and they're only a 45 minute drive away. I would only buy from them if they had it on the shelf as I've heard their lead times are horrible. And as you say, you can wait two weeks before finding out they can't get the part anyway. And their 69030 has been replaced by the thick ring 85239 which is quite a bit more..., around $60 I believe. I passed on an 85239 from Bob for that reason (among others).
A little something I noticed today on a 10-10 that a friend gave me. He was the original owner. Roller in the recoil.
Wow is that clean. Nice looking.
