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rarefish383

rarefish383

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I had the piston on my 7-10 rod backwards, so I was hoping that was why it was hitting. Turned it around and put everything together, not Torqued, and it still hits. So, I got out my cheap calipers. Since the new piston is on the rod and crank, the best place I could measure was from the piston pin to the rod cap. The original rod was about 2.68 inches and the new rod was about 2.72 inches. Oops wrong rod. I wonder how a stroked 7-10 will run, a little grinding and I think it will work? Actually, I'm going to put the new piston on the old rod and start over.
 
rwoods

rwoods

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You too, Ron. That big one looks pretty shy on any useful holding wood on the stump. Someone may have been looking over your shoulder on that one.
You can't see it in the picture, but the hinge on the far side was about 4" thick. The tree was really weighed with limbs on the fall side. I gutted the heart purposely, in case some one wanted a board or two.

That said, on many occasions I wouldn't be back to report if I wasn't being looked over.
Ron
 
Maintenance supervisor

Maintenance supervisor

Every 100yrs, All new people...
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I had the piston on my 7-10 rod backwards, so I was hoping that was why it was hitting. Turned it around and put everything together, not Torqued, and it still hits. So, I got out my cheap calipers. Since the new piston is on the rod and crank, the best place I could measure was from the piston pin to the rod cap. The original rod was about 2.68 inches and the new rod was about 2.72 inches. Oops wrong rod. I wonder how a stroked 7-10 will run, a little grinding and I think it will work? Actually, I'm going to put the new piston on the old rod and start over.
Mmmhhh? Pop up piston?
 
rwoods

rwoods

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Not being critical, sir. Just expressing concern. Glad you had it covered.
No problem, Poge. I appreciate either as I still have a lot to learn. You can see below how much more cutting I was anticipating. I thought I was being generous at 4" hinge with nipped corners and gutted center, but I was wrong. Due to my less than straight cuts the hinge was close to 6" thick in the heartwood which means my estimation was even further off than just what is represented by the root pull.

IMG_6220.JPG

Ron
 
xl130

xl130

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I noticed that the clutch is keyed onto the crankshaft of my 1-72. Was curious why there would be a woodruff key on that side? Balance ?

On a positive note the oiler now works miraculously after the saw spent a few days on its side while the flywheel soaked in penetrating fluid...
 
heimannm

heimannm

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xl - The right hand start saws had a key in the clutch and right hand threads on the crankshaft. If you don't use the key there is a chance the clutch will slip on the crankshaft since the rotation of the saw will tend to loosen the nut. The clutch spiders with the keyway are not as robust as those without a keyway so you need to be careful and not overtighten the nut.

Later saws with left hand starters had no keyway on the PTO side and utilized a left hand thread on the clutch nuts.

Mark
 
matt_lamb_160

matt_lamb_160

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I fitted a HL324a (clone just for a proof of concept) to one of my Super 250s that arrived missing a carb. Fitting it required using a HL63 low profile fuel pump body. I was considering fitting MC49e reeds as well, but the saw started well and I do not want to pull it apart for nothing. I also do not feel the need to test the rpm capacity of the old bearings, etc.. I will probably remove the carb and replace it with a HL63 and use the larger carb and reeds on something that needs a rebuild (I might find a Super 550 by then).

The spacer could be neater and the choke lever isn't ideal, I'll clean this up if I do it again:

 
matt_lamb_160

matt_lamb_160

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Once you collect a few more saws you will have some of the OEM spacers laying around so you won't have to make your own.

Mark
Good reason to keep collecting!

I actually have a few, but the hole (bore) in them is too small for the carb as they all suit the HL63. They will fit, but it is a big restriction. My setup has the plate from a McCulloch carb to center the adapter. For some reason I wanted to space the carb further back which is why I used the thick plate, I can't remember why now. The adapter was easy to make except for the slot for the pulse port.
 
Woodslasher

Woodslasher

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Any comments on the porting on this MC30 block from eBay? The merged transfers and exhaust ports are an interesting approach. The boost port is also interesting (it looks a little low in the picture, but it may just be the angle).

What series is that for? It looks like removable head version of the 1-4* block I was poking at a few weeks ago, I'd say that's some hella-major porting if so. It also looks like they plugged the (flow chamber?) thingy on the right. edit: It's like a doggone kaleidoscope, the more I look the more holes I see.... :dizzy:
 
matt_lamb_160

matt_lamb_160

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What series is that for? It looks like removable head version of the 1-4* block I was poking at a few weeks ago, I'd say that's some hella-major porting if so. It also looks like they plugged the (flow chamber?) thingy on the right. edit: It's like a doggone kaleidoscope, the more I look the more holes I see.... :dizzy:
It is a MC30 kart block. Yes, it is serious porting and yes they plugged the third port and added a boost port instead. I am not sure but I think it might be designed to run with a MC91 style piston.

If the third ports are not already drilled in the cylinder (three holes opposite the exhaust and lower than the exhaust and transfers), you can add boost ports which feed via the third port opening which is filled here (nine porting). If you do this, you also need to remove the divider between the third port passage and the crank case area. You also need to make sure that the carb can only breath through the reeds (block off the third port opening). In this instance they have blocked the third port and are allowing the boost ports more direct access to the crank case. They are also reducing crank case volume.
 
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