May I pick your collective brains about the 394 cylinder?

[RIDE-RED 350r]

OK, so I have my own 394 project in waiting.

Now I know the difference between closed port and open port.

I have been working with my 372 and 357 doing mods and their lower transfer ports are what I consider "normal" as they are designed like what I have found on my ATC and dirtbike engines over the years...

So having said that, what's up with the lower transfer design on the 394 cylinder??? I know they are a closed port design, but I have not come across lower transfers like these until now.

The biggest question I have pertaining to this design is: Can anyone offer any tips, maybe some "do's and don'ts" for these lower transfers? I don't plan to go in there and just start hogging them out. I will be degreeing the port timing and will probably make some moderate changes with exhaust and transfers. But I'm scratching my head with those lower transfers..... Like I said, I don't want to just open them up for the sake of doing it for fear of losing too much transfer velocity.

Any advice is appreciated.

If anyone has some timing numbers they would be willing to share that would be great too. But I understand if numbers are guarded trade secrets. I want to do a good strong woods port on this thing. I have successfully altered port timing on my 372XPW. But I have taken it slow and incrementally and I will be going in at least one more time as I have a couple more changes I have decided to make. Just looking for some ballpark info on what the 394 takes to well..

Thanks guys!

 

[jmssaws]

A 394 is the same design as a stihl,basically identical to a 660 for instance only with much better timing numbers.

I take 050 from the chamber and use
103 120 78 and usually 230 or 240 lbs of compression.

You don't have to take that much from the chamber but these big huskys love compression.

 

[jmssaws]

Here's mine with the above numbers.

 

[RIDE-RED 350r]

Dang Jmssaws, sure giving those blocks hell! I like how that sounds....

I don't have the means to cut the squish, all I can do to bump compression is the base gasket delete.

Do you modify the lower transfers?

Thank you for the numbers, I appreciate it, gives me something to shoot for.

 

[jmssaws]

I just clip the lip on the lowers and that's it.

A gasket delete and 020 off the key and the above numbers will make a terrific running saw.

 

[RIDE-RED 350r]

OK begging your pardon for a relative beginner's question, but what do you mean by "clip the lip"?

Since you mentioned it, I did file the key on my 372 flywheel. I couldn't tell you how beneficial it was as I made port timing changes and installed a black coil at the same time... I certainly don't think it hurt it at all, my 372 is starting to become quite a runner.

 

[jmssaws]

There's a lip at the entrance of the lower transfer,just grind enough where fuel won't puddle.

A 394 has a key likea stihl and likes a advance much more than a 372.

 

[RIDE-RED 350r]

Copy the lip, I get ya now. Thanks

Yes, I recall the 394 having an "old school" separate key as opposed to the key integrated into the flywheel like the 372 and others...

 

[jmssaws]

A 394 is a less is more saw, don't take much to make one run great.

 

[MG2186]

A 394 sounds like a bigger version of a 288 with the 2 port design, the crank key way and intake block


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[RIDE-RED 350r]

A 394 is a less is more saw, don't take much to make one run great.

I have seen it said that the 394 is snottier saw all-round than the 395 and that it takes a little more work on a 395 to yield the same results.

The more you guys talk to me, the more I hope that at least one of the two 394 cylinders I have are salvageable!

 

[jmssaws]

A 394 sounds like a bigger version of a 288 with the 2 port design, the crank key way and intake block


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I've had a couple good running 288's,great saw. Had a awesome running 281 a while back too.

 

[jmssaws]

I have a very sporty 395 also and it lacks the anger that the 94 has. It's just woods ported and not taken as far as my 94 though.

 

[jmssaws]

My 395

 

[jmssaws]

The 95 is
101 120 78 and 215lb it's my falling saw that I run most

 

[Deets066]

I have a 394 project as well, interested to hear some info on this

 

[RIDE-RED 350r]

You converting to the 395 cylinder Deets?? Or did you score an OEM 394 cylinder?


Edit: Wait a sec, that IS a 394 cylinder isn't it!!! Either you did a stellar job cleaning it, or you scored!

 

[jmssaws]

Me and deeter are both hardcore stihl guys but even we have to have a 94.

I love my beloved red light 066 but try as I may I can't make it run like the 94,not even close really.

 

[MG2186]

So a 066 is in between a 385/390 and a 394/395 then? Stronger than 390's but not as strong as a 394's?


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[MG2186]

How much heavier is a 394 than a 385


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