254XP Build. Ideas?

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Jcubb

562XP, 254XP, 51, 350
Joined
Apr 21, 2017
Messages
17
Reaction score
11
Location
Ontario
Hey Everyone,

I'm just picked up a 254XP and I'm looking to do some modifications. I'm not too sure how far I would like to take it at this point but I will for sure be doing a muffler mod and some cylinder port work. I am also considering taking some material off the cylinder base (I would like to run a gasket).

I'm not sure if this particular saw could benefit from an ignition timing advance.

Larger carburetor?

I am already taking apart the case to replace bearings and seals.

Looking to hear some thoughts on what is worth doing and what is not worth doing.
 
I have seen those videos on Youtube. They were very useful when taking apart the saw.

Here is a bit of an update on this thread and what I have done so far:

- Replaced crank bearings and seals
- Replaced the stock base gasket (.040") with a paper gasket (.015) and some Loctite 5009 spray on gasket sealer. This left me with between .019" and .022" of squish
- Filed the flywheel key to get some additional ignition timing
- Opened up the transfer ports
- lowered the intake
- squared off the exhaust port
- Opened up the muffler and the heat shield by drilling out some existing holes inside the muffler and cutting part of the outlet tab off
- Put in a carb kit, fuel filter, spark plug

The saw would start and run fine until I went to cut wood with it. Once I get in to a cut it would die out. This is when I put in the carb kit / fuel filter / plug. Didn't fix the problem. After a while of messing around I found out that the problem I was having was the tank vent.

After that problem I have been having problems with the chain brake case filling up with chips and stalling out the saw. After it stalls it takes me about 1/2 hour to get it going again for some reason. I also seem to be having a bit of a problem getting the saw to idle. I am fairly certain that I have the carb tuned right. The saw also seems to be making a bit of a knocking noise? I couldn't hear it because I had ear plugs in at first. I thought that some of my problems may have been where the timing was set so I set it back to where I believe it was stock; however, the flywheel has a fair amount of play now with the key filed.

I am considering putting the stock base gasket back in in case the knocking noise is the piston touching the top of the cylinder. I am also considering getting out a timing light so I can figure out where the timing is at.


If anyone has some an idea of what the problem could be I'm open to hear.
 
I'm pretty sure it's maple. The wood is fairly dry and has no bark. I'm more concerned about how difficult it is to start the saw after it clogs up than the clogging issue
 
flywheel has a fair amount of play now with the key filed.

When you say play, there's none when the nut is tightened, right?

I have had 154 squish as small as 16 with no interference, but that was just with thin gasket, muffler work, and widening the intake horn, no port work. (You did not mention the intake mod for your 254 -- drill out the restriction just below the filter, and the filterbase too.)

I have had saws make bad sounds when the timing was advanced too much.
 
There is no play in the flywheel when the nut is tightened. I was able to find my timing light today and find the timing with the degree wheel and the light. I am running around 23-25 degrees of timing. I was hoping to run about 20 degrees but it doesn't seem to matter whereIi turn the flywheel... I am still getting the same 25 degrees. There has to be at least 10 degrees of play in the flywheel on the key. I wonder what would cause this to not change my timing?

My biggest problem at this point is that the saw doesn't want to idle down. the lowest idle I can get still allows the chain to move slowly. I wish I had an RPM meter, it would make tuning a lot easier

Im not sure what you mean with the filter restriction... my filter fits overtop of the elbow that comes off the carb.
 
You can expand the inside of the elbow and the hole in the bottom of the filter, by quite a bit. But that is the least of your problems.

It sounds like you have an air leak. Did you pressure/vacuum test the crankcase?
 
I see. I will take a closer look at how to do that modification while I have the saw apart.

I have not done an air leak test on the crankcase as I don't have the required tools. I did find an air leak today though by spraying carb cleaner into onto the intake gasket area. Looks like I will have to replace those gaskets.

Im sure that will solve the vast majority of my problems. I have had quite a few problems with this saw since I got it back together. It's hard to diagnose these things when you have multiple problems at once.
 
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