Author Topic: 7900 Muffler  (Read 947 times)

0 Members and 0 Guests are viewing this topic.

Offline KilliansRedLeo

  • Nitro Hotsaw
  • *******
  • Posts: 2361
  • Karma: 80
  • Location: Rochester, NY
    • RoCHusqvarna
Re: 7900 Muffler
« Reply #10 on: June 19, 2014, 03:57:18 pm »
Piston worked out great 165PSI with the metalized base gasket. Popped on the second pull ran on the third, blip the throttle idles at 25-2600, has a full tank that it has to idle on for a half hour. All in all the piston measured the same as the OEM one, I'm happy, now I can send this orange boy home!
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline Nathaniel Vansickle

  • Piped Saw
  • *****
  • Posts: 468
  • Karma: 92
  • Location: Newcomerstown ,Ohio
Re: 7900 Muffler
« Reply #11 on: June 19, 2014, 07:43:53 pm »
Where did you get the hyway piston? ebay? I just looked through my emails with VEC and they list a 7900 piston as well. so far for me they have been decent pistons.
5105H and 6400H in stock

Performance Outdoor Equipment
performanceoutdoorequipment.com
Dolmar, Echo, Jonsered


Offline KilliansRedLeo

  • Nitro Hotsaw
  • *******
  • Posts: 2361
  • Karma: 80
  • Location: Rochester, NY
    • RoCHusqvarna
Re: 7900 Muffler
« Reply #12 on: June 19, 2014, 09:30:11 pm »
I got it from a guy in Florida. They are also avilable from the guy on e-Bay from Greece!
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: 7900 Muffler
« Reply #13 on: June 20, 2014, 02:35:46 pm »
FWIW, just received the piston/cylinder from Greece. Piston Is nicely cast and machined. Wrist pin bore is light press fit and circlip grooves are machined properly. Looks like the ring is 1.2mm

Cylinder is nice, no extraneous chrome plating in ports or squish. Minor chrome flaw in narrow bridge between the two transfers(both sides) looks like a pinhole.   A few of the oem Stihl ms460 cylinders (Brazil) I've had had similar flaws and were not an issue.

Offline KilliansRedLeo

  • Nitro Hotsaw
  • *******
  • Posts: 2361
  • Karma: 80
  • Location: Rochester, NY
    • RoCHusqvarna
Re: 7900 Muffler
« Reply #14 on: June 20, 2014, 03:19:17 pm »
Adam, that's great! Did it come in a plain box or was it marked e.g. maker?
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: 7900 Muffler
« Reply #15 on: June 20, 2014, 05:02:24 pm »
Tim, generic cardboard box,  very nicely packaged, box in box.  Not gonna port it, curious to see how it works stock. The Bailey's BB was a joke stock! Heavy piston and +.004 thousandth variation in squish from sloppy chrome job. Real pain to machine that irregular buildup from the squish band. Certainly not cost effective unless you have machine tools and then your still out set-up time. Real question in my eyes is if the AM is worth a chit as a bolt on... 

Offline KilliansRedLeo

  • Nitro Hotsaw
  • *******
  • Posts: 2361
  • Karma: 80
  • Location: Rochester, NY
    • RoCHusqvarna
Re: 7900 Muffler
« Reply #16 on: June 20, 2014, 05:18:24 pm »
Looking forward to your report! Thanks Adam!
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline aclarke

  • Nitro Hotsaw
  • *******
  • Posts: 1676
  • Karma: 172
Re: 7900 Muffler
« Reply #17 on: June 25, 2014, 11:24:48 pm »
Ran the stock AM jug and piston for a 3-4 tanks last week at the yard bucking up wood in our dump pile. Ran great and after the 2nd/third tank it was noticeably more powerful. I'm not too keen on the Asian AM jugs and I feel this kit is superior. 

Couldn't resist and conservatively ported the cylinder. Widened out the transfers a small amount, widened intake(no lowering) and widened and raised the exhaust a small amount.  Ended up using an 046 piston and a 1MM spacer under the jug with thin paper on both sides. This combinations yielded .014 squish which is too tight. Milled the top of the piston to get 23-24 thou and ran it with a single ring.  Really peppy and still a ton of torque. Gonna run it in a stock appearing 5 cube gas race this coming weekend, let you know how it places. Adam
 

Offline KilliansRedLeo

  • Nitro Hotsaw
  • *******
  • Posts: 2361
  • Karma: 80
  • Location: Rochester, NY
    • RoCHusqvarna
Re: 7900 Muffler
« Reply #18 on: June 26, 2014, 08:15:18 am »
Cool, I will order one up. You put this on a stock 7900 or a stroked saw? What attracted you to an 046 piston over stock? Good luck at the races! ;D
"When the people fear the government...you have tyranny....When the government fears the people....you have liberty"

Thomas Jefferson
1743-1826

Offline adam32

  • Piped Saw
  • *****
  • Posts: 429
  • Karma: 46
Re: 7900 Muffler
« Reply #19 on: June 26, 2014, 09:16:59 am »
Ran the stock AM jug and piston for a 3-4 tanks last week at the yard bucking up wood in our dump pile. Ran great and after the 2nd/third tank it was noticeably more powerful. I'm not too keen on the Asian AM jugs and I feel this kit is superior. 

Couldn't resist and conservatively ported the cylinder. Widened out the transfers a small amount, widened intake(no lowering) and widened and raised the exhaust a small amount.  Ended up using an 046 piston and a 1MM spacer under the jug with thin paper on both sides. This combinations yielded .014 squish which is too tight. Milled the top of the piston to get 23-24 thou and ran it with a single ring.  Really peppy and still a ton of torque. Gonna run it in a stock appearing 5 cube gas race this coming weekend, let you know how it places. Adam
 

Don't worry Adam...I'll post a video of my 372 spanking your 7900 for all to see...hahahahhahaha

 

Related Topics

  Subject / Started by Replies Last post
28 Replies
2266 Views
Last post April 09, 2016, 02:02:55 pm
by computeruser
25 Replies
898 Views
Last post February 18, 2015, 10:59:36 pm
by Ducksnuff870
15 Replies
665 Views
Last post June 20, 2014, 07:14:42 am
by Chainsawr
6 Replies
139 Views
Last post June 14, 2014, 02:48:05 pm
by KilliansRedLeo
0 Replies
191 Views
Last post June 21, 2014, 11:32:53 am
by KilliansRedLeo
1 Replies
300 Views
Last post July 16, 2014, 02:45:06 pm
by fuzz1500
8 Replies
323 Views
Last post May 08, 2015, 12:21:49 am
by aclarke
3 Replies
416 Views
Last post January 03, 2016, 03:19:17 pm
by Eccentric
35 Replies
297 Views
Last post January 27, 2016, 03:28:50 pm
by Cut4fun .
3 Replies
285 Views
Last post December 08, 2017, 01:25:19 pm
by Tractorsaw1