Modding the Dolmar 420

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I sacrificed my clean truck for a log to test this 420 in, lol:). I touched up the chain with a file on a jig for a nice clean reproduceable edge. The wood is a little bit splintered on the end, but this was best I could do for tonight and I want to get going on this thing. I'll be out of town next week for work. I tuned the saw right up to the limiter at about 13,100.

Actually the first thing I did with it was to swap on a 5100S coil in order to move the rev limiter higher. Strangely, the saw wouldn't even run. It had spark but would not fire. So back on went the stock coil.

After timing the saw as I received it, I then modded the muffler and retimed the saw. The results were interesting. Giving the saw a normal bite as you would in normal use, I only picked up about 5% or a little less. But when lugging the saw down, I picked up 13% to give the best time of the evening. I even bested the time of the ported Redmax! That 190+ PSI is really shining through.

Next I'll be pulling it apart and porting the cylinder. More timed cuts will be coming after that.

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Great video there, Brad!:rock:
 
Good stuff. Looks like one heck of a saw. If my wife will give me permission I might need to go get one from my dealer.
 
Beam style connecting rod with a caged bearing. No clamp in the intake.
471847957_GaGhN-M.jpg


Three open transfer ports per side.
471847993_guS8T-M.jpg


Plenty of meat around the ports for port work.
471848097_ZFReb-M.jpg
471847909_Lu7XT-M.jpg


Exhaust.
471848074_ySFwY-M.jpg


Intake.
471848038_3FA24-M.jpg


Here's what I like to see. Lots of room to widen the ports on both the intake and exhaust.
471847772_hz6RY-M.jpg


A little casting cleanup will be in order.
471847902_Syi27-M.jpg
 
what is the number of the comparable makita saw? i can seem to see a dcs420 on their site. Thanks. :)
 

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