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General control line discussion => Open Forum => Topic started by: paulwells66 on October 01, 2020, 10:34:13 AM

Title: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: paulwells66 on October 01, 2020, 10:34:13 AM
I took the back plate off my g21 40 (B29) and noticed a small amount of play in the bushing at the crank. you can feel a small click when rotating the crank back and forth.
Assuming it's been like this for a while. In any case would like to fix it before something bad happens. Anybody have suggestions, new rod, re-bush, ?

thank you!

Paul Wells
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: paulwells66 on October 01, 2020, 11:07:29 AM
Ah!  thank you so much. I would guestimate it to be about that. You made my day!
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: M Spencer on October 01, 2020, 11:23:27 PM
Most of the 21 series rods are interchangeable , so not to awkward to get em . If needed .
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: paulwells66 on October 02, 2020, 09:19:33 AM
that's good to know...I have a B29 but could only find rods for other 29 models.
I tried to remove the liner after a crash to clean it but was frozen so just left it alone..figured no reason.
If ever do have to change the rod curious how I will get it out e.g. heat? penetrating oil? ?
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: Peter in Fairfax, VA on October 02, 2020, 11:22:20 AM
I'd heat the case in a 225 degree oven to pull the liner, possibly mounting a prop and putting a wide, soft piece of wood in the exhaust port to let the piston lift it if nothing else worked.
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: Dan McEntee on October 02, 2020, 05:14:39 PM
  I think most if not all St liners are a slight shrink fit into the case. Randy Smith could shed some light on this for sure. You don't want to force it or gall it during removal. It needs that fit for proper heat transfer for proper cooling.
   Type at you later,
  Dan McEntee
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: M Spencer on October 02, 2020, 09:21:17 PM
that's good to know...I have a B29 but could only find rods for other 29 models.
I tried to remove the liner after a crash to clean it but was frozen so just left it alone..figured no reason.
If ever do have to change the rod curious how I will get it out e.g. heat? penetrating oil? ?

GGAAARRRRRHHHHHH !N . VD~

Use a srewdriver THAT FITS . Things . !

remove the reaer wrist pin access screw .

Heat case & lift liner JUST CLEAR of that hole in the rear .

Use heat gun , C.R.C. , WD 40 . penetrating oil . Singer Sewing Machine oil , to heat up inside piston . Backplate OFF .

A pin with a 25 thou .  :-\ 90 degree or more HOOK on the end , held in pliers , ookitin & P u l l l l .Holding jaw correctly , one eye squinted , most weight on left leg .

AA 29 ** ! is PART NUMBER not TYPE ! .  H^^
Title: Re: Super Tigre G21 40 play in connecting rod bushing at crank. Suggestions please.
Post by: RandySmith on October 03, 2020, 12:43:17 PM
I took the back plate off my g21 40 (B29) and noticed a small amount of play in the bushing at the crank. you can feel a small click when rotating the crank back and forth.
Assuming it's been like this for a while. In any case would like to fix it before something bad happens. Anybody have suggestions, new rod, re-bush, ?

thank you!

Paul Wells

Just FYI  the  G21-40   uses the same  rod as the  46, not the  29 or 35, But  disclaimer  the  G21 40 and 46  has  had  more than 5 different rods, and  2 different lengths,  Is this a  double or single ring motor ?

Randy