Aww dang I wish I had cash not buzy https://www.trademe.co.nz/4445310802
McCulloch Chain Saws
- Thread starter Bruce Hopf
- Start date
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Can anyone tell me if this piston will work in a McCulloch 1-75? it the right diameter.
https://www.amazon.com/dp/B08G8X79Z...9MVAR5NH&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
https://www.amazon.com/dp/B08G8X79Z...9MVAR5NH&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
Jethro - US $1,550 may be a good price for one in your neighborhood, seems a bit high to me but it is probably a good price where you are located. Saw looks to be complete, even has the muffler cover in place. From the color scheme I'd guess it it a 125C model.
Dake - The 1-75/1-85 saws had a thin ring piston originally (48904), the one LRB is selling is a thick ring. From the IPL's the wrist pin bearings are the same so the wrist pin diameter should be O.K., not sure about the deck height of the two pistons.
I've had a few issues with LRB pistons, wrist pins don't fit properly in the 10 Series or 600 Series saws (too small), ring grooves not cut deep enough on one for a 70cc McCulloch, new piston for the PM650 (94130) was around 0.0006" smaller than the original. All that said, when there is nothing else available the LRB piston could still be the best option. You have to give them credit for going out on a limb and having these pistons made.
My inventory says I have one new 48904 piston assembly on hand (piston, rings, bearings) $85.00 + shipping if you are interested.
Mark
Dake - The 1-75/1-85 saws had a thin ring piston originally (48904), the one LRB is selling is a thick ring. From the IPL's the wrist pin bearings are the same so the wrist pin diameter should be O.K., not sure about the deck height of the two pistons.
I've had a few issues with LRB pistons, wrist pins don't fit properly in the 10 Series or 600 Series saws (too small), ring grooves not cut deep enough on one for a 70cc McCulloch, new piston for the PM650 (94130) was around 0.0006" smaller than the original. All that said, when there is nothing else available the LRB piston could still be the best option. You have to give them credit for going out on a limb and having these pistons made.
My inventory says I have one new 48904 piston assembly on hand (piston, rings, bearings) $85.00 + shipping if you are interested.
Mark
thanks for the help Mark . some how I ended up with enough parts to make a second rat saw.
Only one more saw???
I did check in to the 53941 compared to 48904 pistons (actually I have 53944 which is 0.030 oversize) and there are significant differences.
53944 on the left, 48904 on the right, as noted, 53941/44 is thick ring, 48904 is thin ring.
The two pistons are different lengths, approximately 1.670" for 48904 and 1.594" for 53944.
I stuck a wrist pin in the two to try and align them as they would fit on the connecting rod and 48904 is about 0.015" longer below the wrist pin. This is probably not important.
The deck height (wrist pin to top of piston) for 53941 is about 0.065" shorter than 48904, this would definitely be a problem with low compression and would change the port timing pretty significantly.
Just FYI stuff.
Mark
I did check in to the 53941 compared to 48904 pistons (actually I have 53944 which is 0.030 oversize) and there are significant differences.
53944 on the left, 48904 on the right, as noted, 53941/44 is thick ring, 48904 is thin ring.
The two pistons are different lengths, approximately 1.670" for 48904 and 1.594" for 53944.
I stuck a wrist pin in the two to try and align them as they would fit on the connecting rod and 48904 is about 0.015" longer below the wrist pin. This is probably not important.
The deck height (wrist pin to top of piston) for 53941 is about 0.065" shorter than 48904, this would definitely be a problem with low compression and would change the port timing pretty significantly.
Just FYI stuff.
Mark
The 48904 is for the 1-75. so how can that piston on amazon fit like 10 different saws?
That is not an easy question to answer as none of us were in the McCulloch engineering or marketing group at the time. McCulloch did utilize quite a lot of common parts, but is seems the early models especially included many changes/improvements as well. The same sort of early changes/later standardization impacted the 10 Series models as well. McCulloch was very innovative and seems like they were constantly changing things, often times the documentation failed to keep up.
The BP-1 saws were only in production for 9 months or so, and yet there are two very different design fuel tanks out there, and perhaps as many Service Bulletins issued for those saws as any that McCulloch produced.
All of this makes supplying parts a real challenge when folks don't use part numbers...someone will call and want a coil for an Eager Beaver...problem is there were maybe 5 or 6 distinctly different models that used the Eager Beaver moniker...
In some cases, you must have the model and serial number from your saw and the matching IPL to correctly identify the actual parts required. For example, some PM55 saws used a piston without locating pins for the ring ends, and later models had pinned rings. Some guys will neglect to match their serial number to the IPL and get the wrong parts...
And then you have purchasing out looking for the lowest cost vendors...and often part number changes for the same function part...makes it interesting.
Mark
The BP-1 saws were only in production for 9 months or so, and yet there are two very different design fuel tanks out there, and perhaps as many Service Bulletins issued for those saws as any that McCulloch produced.
All of this makes supplying parts a real challenge when folks don't use part numbers...someone will call and want a coil for an Eager Beaver...problem is there were maybe 5 or 6 distinctly different models that used the Eager Beaver moniker...
In some cases, you must have the model and serial number from your saw and the matching IPL to correctly identify the actual parts required. For example, some PM55 saws used a piston without locating pins for the ring ends, and later models had pinned rings. Some guys will neglect to match their serial number to the IPL and get the wrong parts...
And then you have purchasing out looking for the lowest cost vendors...and often part number changes for the same function part...makes it interesting.
Mark
Tony Mayhew
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I had someone give me a McCulloch 7-10 for making his power washer run again and man oh man! That old boy is a ear drum rattler! And someone just gave me a double eagle 80 McCulloch for free! I have not had the opportunity to get it running yet but looks to be a go getter of a saw from what I can tell?
Crazy money
The de80 is an 82cc mac. Of couse its a go getter. They are unique though with their design compared to other 82cc macs. Ive got 2 of them and can tell ya they cut strong and run great. Heavy but good saws. What would wake it up is a 850 muffler and a non governed carburetor....but id also argue that carburetor has likely saved a few of them from destruction.
Yup , put a 850 muffler on my PM800 original muffler just a giant restricted heat sink terrible design, Made it run and sound like a real Mac should be like,
That 125 been for sale for a while apparently so is indeed too much.
Good scores
. Yes I tend to run both plugs and muffs with the Mac's
This is loud but boy did it pick up some power
Also with the added noise it also added a proper 4 stroke pop pop pop and much easier to tune. I hated that with the belly can. At full song the 4 stroke was hard to hear
Good scores
. Yes I tend to run both plugs and muffs with the Mac's This is loud but boy did it pick up some power
Also with the added noise it also added a proper 4 stroke pop pop pop and much easier to tune. I hated that with the belly can. At full song the 4 stroke was hard to hear
That looks like a 10-series bark box!That 125 been for sale for a while apparently so is indeed too much.
Good scores
This is loud but boy did it pick up some power View attachment 1132375
Also with the added noise it also added a proper 4 stroke pop pop pop and much easier to tune. I hated that with the belly can. At full song the 4 stroke was hard to hear
Hahaha yup. The 1st iteration I had a flat with louvers in it and was pretty happy. Out cutting 1 day I thought wow this thing is cutting good and then next fill up I spotted why. The louvered cover had broken in half and had a massive hole for an outlet. The next version I sorta copied off Tim(fossil) sp81 or something from memory.
The bottom wind deflector for the duct conversion came from Ron and his pictures
The Titan 50/57 and DE50 saws use a Walbro HDA77 carburetor, and as an alternate the HDA46. The HDA77 seems to be in high demand, does anyone know if there are actual differences between the 46 and 77 or is it just perception?
Edit - I will add that the HDA46 has a 3/4" throttle bore, I don't have a 77 on hand to compare.
Mark
Edit - I will add that the HDA46 has a 3/4" throttle bore, I don't have a 77 on hand to compare.
Mark
Hi Mark,
I don't have spec's on the throttle bore but do have on the venturi. The throttle valve on both use 34-124 so I would assume the bores are the same.
Both the 46 and 77 have a 15.8 mm venturi and both have the same cartridge check valve, 86-583.
I would say from the info above there wouldn't be any difference in performance.
Thank you Tim. That is good information to have.
Mark
Mark
KUBOTA OWNER
ArboristSite Operative
Not sure if this is the correct place to ask? But i'm trying to get a old 250 running correctly.
Will start and run with a little fuel down the carb bore and will stay running and while trying to adjust it will stall unless i half choke it. Will not accel at times and just runs funny, first seem very rich and then lean. Cleaned up the carb and replace fuel line.
And how should you use the choke if it is spring loaded, hard to hold choke on and pull cord!!
Strange that it work like that.
Will start and run with a little fuel down the carb bore and will stay running and while trying to adjust it will stall unless i half choke it. Will not accel at times and just runs funny, first seem very rich and then lean. Cleaned up the carb and replace fuel line.
And how should you use the choke if it is spring loaded, hard to hold choke on and pull cord!!
Strange that it work like that.
Nice old roller nose cleaner up a little, the 125’s will like it , 36” .404 , 
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