UK Karting - Notice Board (2-Stroke Karting) : Re: any tips how to put the gudgeon pin in conrod

Notice Board (2-Stroke Karting)

Re: any tips how to put the gudgeon pin in conrod
Posted by 'bt3962' on 02 Mar 2009 @ 19:27

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bt3962Joined: January 2002
Total Posts: 12
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Heat the piston with a hot air 'gun' (not your sister's hair dryer!) to a temperature that you can still hold/support the piston. You must have a dummy gudgeon pin!!!

IMPORTANT. Stuff rag or paper towel into the crank case so if any bits fall down they do not go into the crankcase.

Having removed the circlips with a pair of long nosed pliers use the dummy pin to push the gudgeon pin out. The dummy pin may 'stick' when initially inserting into the piston as the circlip groove is usually 'swollen' by the circlip. Twist it to aid insertion. I find a 1/4 inch socket extention is just the right size to insert inside the dummy pin allowing you to press with thumb or tap the dummy pin through. You must support the piston with your other hand and do not force the piston against the conrod. This will damage the con rod and big end. Not good.
The dummy pin displaces the gudgeon pin such that the piston can be lifted off the con rod. DO NOT PUSH ALL THE WAY THOUGH. It is easy to push the dummy pin too far. Do not use force to lift the piston off. It comes away easily when you get it right. Note that the 2 steel washers are next to the conrod and roller bearings and the aluminium washers are next to the piston. Always replace the aluminium washers as they have been known to break up. Been there. Not good.

Replacement is the reverse. Carefully insert the rollers around the dummy pin. This is when you will appreciate the rag in the crankcase. I have not used grease doing this but a drop of castor oil into the slot in the top of the conrod is a good idea just before re-assembly.

Before putting the piston onto the conrod practice (preferably with old piston and circlips) inserting the circlips back into the circlip groove with a pair of GOOD long nosed fine tiped pliers. It is much easier without the gudgeon pin in!. Have a few spares as initially you will have some circlips go somewhere. If you fine them let me know as I have ever only found one! I grip the circlip 2-3 mm from the gap at about 4 o'clock and use an upward movement and anticlockwise twist to fit the pliers into the cut-away in the piston. Strong wrists are required. When you have mastered this you can try it on the real thing. Make sure the circlip is actually in the groove. I also move the circlip gap past the piston cut-away. Makes getting the circlip out easier.

Put the piston back onto the conrod THE CORRECT WAY ROUND. Top ring gap facing FORWARDS. Always fit new circlips. Always buy 4 circlips until you are really good at fitting them. Too much force bends them and they may come out when racing with unpleasant consequences.

Have patience. Do not use excess force. Take a rest and come back to it if not first sucssessful. It is all down to tecnique.

Good luck

Message Thread:

do you have to put the small end in by 'tkmkart' (01 Mar 2009 @ 16:33)

Re: do you have to put the small end in by 'Farrang' (01 Mar 2009 @ 18:56)

Re: do you have to put the small end in by 'tkmkart' (01 Mar 2009 @ 19:14)

Re: do you have to put the small end in by 'Traxtar' (01 Mar 2009 @ 19:17)

Re: do you have to put the small end in by 'Farrang' (01 Mar 2009 @ 19:40)

Re: do you have to put the small end in by 'Farrang' (01 Mar 2009 @ 19:44)

Re: do you have to put the small end in by 'tkmkart' (01 Mar 2009 @ 20:05)

Re: do you have to put the small end in by 'Nottbowerpower' (01 Mar 2009 @ 21:52)

any tips how to put the gudgeon pin in conrod by 'tkmkart' (02 Mar 2009 @ 6:53)

Re: any tips how to put the gudgeon pin in conrod by 'Hootsman' (02 Mar 2009 @ 7:08)

Re: any tips how to put the gudgeon pin in conrod by 'tkmkart' (02 Mar 2009 @ 9:52)

Re: any tips how to put the gudgeon pin in conrod by 'iant' (02 Mar 2009 @ 11:11)

Re: any tips how to put the gudgeon pin in conrod by 'tkmkart' (02 Mar 2009 @ 11:34)

Re: any tips how to put the gudgeon pin in conrod by 'iant' (02 Mar 2009 @ 11:43)

Re: any tips how to put the gudgeon pin in conrod by 'TKMrulez' (02 Mar 2009 @ 11:48)

Re: any tips how to put the gudgeon pin in conrod by 'tkmkart' (02 Mar 2009 @ 11:54)

Re: any tips how to put the gudgeon pin in conrod by 'tkmkart' (02 Mar 2009 @ 12:16)

Re: any tips how to put the gudgeon pin in conrod by 'iant' (02 Mar 2009 @ 15:59)

Re: any tips how to put the gudgeon pin in conrod by 'tkmkart' (02 Mar 2009 @ 17:21)

Re: any tips how to put the gudgeon pin in conrod by 'bt3962' << You are here!

tips how to assemble small end by 'tkmkart' (03 Mar 2009 @ 10:46)

Re: tips how to assemble small end by 'Polo1272' (03 Mar 2009 @ 11:13)

Re: tips how to assemble small end by 'iant' (03 Mar 2009 @ 11:20)

Re: tips how to assemble small end by 'iant' (03 Mar 2009 @ 11:18)

Ian...... by 'itpro' (03 Mar 2009 @ 11:23)

Re: Ian...... by 'tkmkart' (03 Mar 2009 @ 11:31)

Re: Ian...... by 'iant' (03 Mar 2009 @ 11:38)

Re: Ian...... by 'tkmkart' (03 Mar 2009 @ 11:43)

Re: Ian...... by 'iant' (03 Mar 2009 @ 11:52)

Re: Ian...... by 'itpro' (03 Mar 2009 @ 12:47)

Re: Ian...... by 'drewdt3' (03 Mar 2009 @ 17:20)

Re: tips how to assemble small end by 'tkmkart' (03 Mar 2009 @ 11:26)

Re: tips how to assemble small end by 'tkmkart' (03 Mar 2009 @ 11:48)

Re: tips how to assemble small end by 'itpro' (03 Mar 2009 @ 12:51)

Re: tips how to assemble small end by 'tkmkart' (03 Mar 2009 @ 15:59)

Dummy gudgeon pin by 'bt3962' (03 Mar 2009 @ 16:16)

Re: Dummy gudgeon pin by 'drewdt3' (03 Mar 2009 @ 17:23)

Re: Dummy gudgeon pin by 'tkmkart' (03 Mar 2009 @ 17:39)

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