Carburetors - Custom or High Performance Installations

[Davey83]

I use it for cutting timber everyday. Well almost everyday. It is not running right as of late need to investigate it. Just not a lot of time to do it. Just have to be a little more mindful of sticks and things not to tear a hole in it. If it is something you would like to try I can give you some more details and pics to help you along.

Yes I would appreciate that.

 

[jmester]

Cool, I will work on it this evening after work.

 

[jmester]

 

[jmester]

The second pic is how I modified the filter base to work with the 394 filter horn.
The third pic shows a stock un modded filter base.
And yes that is clear silicon just wanted to make sure it was sealed. At the mounting surface between filter base and filter horn.

 

[jmester]

 

[jmester]

First pic shows stock carb studs and modded studs.
Second pics is the overall length of the modded carb studs
Third is the overall length of the stock carb studs
Sorry about the ruler I had it since I was a kid. Funny I used the same ruler to modify Estes model rockets back in the day.

 

[jmester]

 

[jmester]

Just some mock up pics.
Notice in the second pic the brass bushing / spacer. They are 4.5 mm thick. I used the bushing out of a busted 660 top cover. You need them so you don't break the horn or filter base when you tighten the nuts down.

 

[jmester]

 

[jmester]

First pic - modded filter horn. I cut the two tabs off and ground some plastic away where the nuts go to give some clearance. The one with tabs is one from a 395. They are different from the 394.

Second pic - connecting nuts and washers. I just used some small flat washers that I had. The connecting nut can be got at a hardware store. I could only get fractional thread sizes so I bought the smaller one they had. Then I drilled and tapped the to M5 x .80.

 

[jmester]

I am working on a different design. That may make it easier then making longer studs.

 

[jmester]

 

[jmester]

First pic - mod carb box old studs removed and re drilled to a letter I drill bit or .2720.
Second pic - are from a ms 201t carb box. In there stock form they are to long and stick in to the carb box two far and prevent a good carb to intake boot seal. They need to be shortened to where they are around 11 to 12mm long

 

[jmester]

 

[jmester]

201t carb nuts installed with intake boot installed to show clearance.

 

[jmester]

 

[jmester]

Above pics - this is the way that husky does it. So it should work just fine for a Stihl. Need to get some different bolts that will clear the horn. Have some on the way from Nate aka fordf150. Will post it finished when I get the other bolts.

If you use a 395 filter horn you will need to drill out the mounting holes using a 13/64 drill bit to use the 5M bolt or to slide it on the extended carb studs. IMO the 394 filter horn is way better. Let me know if you have any questions. Hope this helps

 

[jmester]

 

[jmester]

Got some bolts from Nate. The heads need to be ground smaller to clear the filter horn. Plus they need to have 5mm of threads cut off the end.

 

[jmester]

Found that the horn needs some inserts to prevent it from crushing. Had to drill the holes in the horn to 1/4" for the brass tubing I had. Gets pretty thin in the walls of the horn but works well.