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Engine basics => Engine set up tips => Topic started by: Steve Agrella on July 31, 2011, 07:06:26 PM

Title: LA 25
Post by: Steve Agrella on July 31, 2011, 07:06:26 PM: i just picked up a LA 25 on flea bay, I stole it for $45 brand new in the box ;D

Anyway I purchased a FP25 needle valve assy and venturi, I want to remove the remote needle assy stock plastic back , what back should I use.
Title: Re: LA 25
Post by: Steve Helmick on July 31, 2011, 08:08:29 PM: If you can find a backplate for a .20/.25 FP, or TT .25GP, they will work. The trick is finding one. The easy alternative is buying a new CNC'd barstock backplate from Curtis Shipp, a member here on Stunthanger. Look under "Members". About $12 plus postage. Curtis' address is: m14m21(at)bellsouth(dot)net

While you're at it, replace the screws with socket heads from the local R/C car store. The head screws are 3mm x .5mm, but the backplate screws are 2.5mm x .6mm. Take samples for lengths, 'cause I don't remember. I also like to replace the metric hex 1/4-28 prop nut with one that has an SAE hex...a Gr.8 from the local hardware store. H^^ Steve
Title: Re: LA 25
Post by: Steve Agrella on July 31, 2011, 09:33:12 PM: Thanks Steve
Title: Re: LA 25
Post by: Luiz Ribeiro on August 01, 2011, 06:18:38 AM: Recently I bought from Tower Hobbies, for an O.S .25 LA, the back plate of TT GP .25 and the socket head screws for it, the socket head screws are made for RC cars. The manufacturer's numbers of those items in Tower Hobbies are:

ASCG2917 Associated Screw Set AE .15 12 (4 of 2.6X12mm; 8 of 2.6X7mm)
ASCC9454 Associated Socket Head Cap Screws M3X12mm (12)
TTRG8023 Thunder Tiger Back Plate GP-25

The original screws from O.S. for use in the back plate are 2.6X8mm, but you can use the 2.6X7mm from Associated, because the aluminum back plate of TT is 1 mm less thick than the original plastic of O.S. The originals O.S. for head are 3X12mm.
Of course, this way you will be paying for and getting a lot more screws (3X more) than you really need.

Luiz
Title: Re: LA 25
Post by: Steve Agrella on August 01, 2011, 09:46:04 AM: Thanks Luiz, I just ordered these from Tower, the TT aluminum back is only $5 what a deal
Title: Re: LA 25
Post by: Luiz Ribeiro on August 01, 2011, 01:20:17 PM: Optionally, for head, you can buy from Tower:

LXSAU5 Axial Cap Head M3X12mm black oxide (10)

Good Luck. Luiz
Title: Re: LA 25
Post by: Neil Campbell on November 13, 2011, 06:40:00 PM: I too just recently purchased a LA 25,, I have a os needle valve assembly and a thunder tiger back plate......Question is Do I need a gasket for the metal back plate? the os with the plastic does not have a gasket. which one from thunder tiger would I need
Title: Re: LA 25
Post by: Bill Little on November 14, 2011, 08:40:13 PM: Quote from: Neil Campbell on November 13, 2011, 06:40:00 PM
I too just recently purchased a LA 25,, I have a os needle valve assembly and a thunder tiger back plate......Question is Do I need a gasket for the metal back plate? the os with the plastic does not have a gasket. which one from thunder tiger would I need

Hi Neil,

Several answers on your other thread. I use automotive gasket maker (in the tube). 20 years or more now and no problems.

Big Bear
Title: Re: LA 25
Post by: Russell Shaffer on November 16, 2011, 08:50:06 AM: If you use gasket goop, be sure to read the label. Old style black Permatex cleans up with alcohol. Found this out the hard way.
Title: Re: LA 25
Post by: Chad Hill on November 16, 2011, 08:26:02 PM: RSM makes a round backplate gasket for the LA25 (no dog ears). They also make delrin verturis for them.