stihl 150 porting tips?

[NorcalFlyingsquirrel]

Just tore apart a ms 150 as its allowed at work, to give it some sauce and was wondering if anybody has any tricks to getting this thing anywhere near a ported 2511. without machine work my 2511s pull a 14" bar with Didnt realize it was a strato, smaller bore with a longer stroke. i searched and didnt find anything, maybe use a 151piston and cut the pop out of the 150 cylinder, worked nice with the 201 v1&2 for a torque beast. Ill time it in the morning and try to see what they were up to. Also did any body try gutting the strato? thanks, surprised theres no build or port threads or numbers for these little saws. thanks,

 

[Ketchup]

150/151 both port pretty well with base cuts and piston mods. I’ve put 151 pistons in a few 150s and it’s very similar to how it works on a 201. I think I prefer the 151 over a hybrid 150/151. I might even prefer a traditional band cut in a 150. They seem to rev higher.

I found good gains raising the flange at the transfer lowers.

Unfortunately, I think opening the muffler causes them to be a little slow to return to idle. But you have to open the muffler.

They take a timing advance well, but the key is tiny. I take 1/3 the key and tighten it by hand AFTER putting the clutch back on. I use an impact for the clutch but if you put it on second the vibration loosens the flywheel nut. Then you strip the key the first time you pull the starter.

 

[Ketchup]

Anybody want to see inside a 151t?

I have another one of these on the bench right now. Thought I’d share. Everything except that little chainsaw heart on the right is the same as a 150t. Mostly a basket of plastic bits woven together and tacked with t-20 screws. They come apart fine once you’ve done a couple but I can’t help...

opeforum.com

 

[EFSM]

They take a timing advance well, but the key is tiny. I take 1/3 the key and tighten it by hand AFTER putting the clutch back on. I use an impact for the clutch but if you put it on second the vibration loosens the flywheel nut. Then you strip the key the first time you pull the starter.

I recently rebuilt a 395 for a customer and they used it a few days before breaking a clutch spring. They replaced the springs and tightened the clutch back down with a 1/2'' electric impact (tightening against the starter rope, of course). That instantly stripped the flywheel key, but thankfully they're quite affordable at 170$ new....

 

[Ketchup]

I recently rebuilt a 395 for a customer and they used it a few days before breaking a clutch spring. They replaced the springs and tightened the clutch back down with a 1/2'' electric impact (tightening against the starter rope, of course). That instantly stripped the flywheel key, but thankfully they're quite affordable at 170$ new....

Ouch. If you’re cheap you can set the stripped FW by marking it and the end of the crank. Then carefully tightening it. I have also cut a slot into the FW that will fit a key. A small broach set is handy for that but it can be done with needle files.

 

[EFSM]

Ouch. If you’re cheap you can set the stripped FW by marking it and the end of the crank. Then carefully tightening it. I have also cut a slot into the FW that will fit a key. A small broach set is handy for that but it can be done with needle files.

I considered something like that and may have done it if it was mine. I was able to source a used flywheel for much more reasonable than a new one.