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dolmar PS-421 mods

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RedFir Down

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Looks good Nate! How much gain do you see out of a muffler mod like this? Not to mention the other benefits of getting rid of the CAT.
Where would you recommend a guy to look for a DD tool? Thats about the only one I dont have.
 
fordf150

fordf150

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I don't know about the true gains. Never took the time to video and time cuts on one before and after. Even without any performance gains the reduction in heat is well worth it. This saw took an extra 1/4 turn on the high side to get 13000 for break in. Don't know how it was tuned before hand though. DD tool is find a willing dealer to supply you one or ebay. There is spline, D and DD plus the pac man screw driver.
 
MS460WOODCHUCK

MS460WOODCHUCK

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I don't know about the true gains. Never took the time to video and time cuts on one before and after. Even without any performance gains the reduction in heat is well worth it. This saw took an extra 1/4 turn on the high side to get 13000 for break in. Don't know how it was tuned before hand though. DD tool is find a willing dealer to supply you one or ebay. There is spline, D and DD plus the pac man screw driver.

Do you have any pics of these screw drivers or is there other names for them? I just looked on ebay and could not find any d or dd screw drivers.
 
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I don't know about the true gains. Never took the time to video and time cuts on one before and after. Even without any performance gains the reduction in heat is well worth it. This saw took an extra 1/4 turn on the high side to get 13000 for break in. Don't know how it was tuned before hand though. DD tool is find a willing dealer to supply you one or ebay. There is spline, D and DD plus the pac man screw driver.
Good to know. I bet the saw does run a lot cooler. Plus im sure the improved throttle response is nice for a saw that size.
Also thanks for the heads up about the occasional issue with the fuel line coming loose.
 
fordf150

fordf150

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This saw didn't get it but I took a couple pictures just to show what is needed for installing a .325 bar and chain on these saws. A clutch drum and bar from a 5105 plus a 10x16x.2 mm shim is needed. This is probably a worthwhile modification just to have rim sprockets instead of spur. The bar needs slight modification to allow it to oil. We drill 2 holes in the groove down through into the adjuster holes. Black lines show where to drill. That is how I run mine and have set a few up to run it. Haven't ran anything but a 16" .325 on these but sticking with 3/8LP an 18" bar is pretty common. cell 012.jpg cell 013.jpg cell 015.jpg
 
fordf150

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I use that almost oval shaped edge that surrounds the gills as my guide to cut the opening larger. just removing the cat is a good start. I will take mine apart and snap a picture of the finished opening. I forgot to take a picture of the finished product when I did this thread.
 
wildroamer

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Hey thanks, I appreciate it! That said, I may just go ahead and order the catless muffler, as it is only around $35 or so I think. That might allow me to do this mod sooner, and replace stock muffler for any warranty work...
 
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