GT550 engine rebuild questions
Posted: Sat Jul 01, 2006 9:48 pmYup my GT is in a million bits- all I wanted to do was replace the base, head and valve cover gaskets as there were significant oil leaks there. It also had (I think I have fixed these) a couple of oil leaks underneath which annoyed me too, but I have replaced o-rings there.
It has been quite a learning curve- the cleaning processes alone have taken days and I am suffering really buggered, sore and cut up hands.
What I discovered when I disassembled the engine was that two rings had frozen in their pistons (both middle rings on pistons 3 & 4) and that the piston skirts had scraped on the bores, leaving some alloy behind.
I sanded the alloy off the cast iron bores and along with the hone I had done professionally, the bores look A1- and still on original specs.
The 3 & 4 pistons however have been a bitch to clean the ring lands on- my first attempt I thought was ok, but when I tried to install the barrells, both 2nd rings broke. (they were new and cost $80) I have since spent another 2.5 hours cleaning the ring lands out with broken rings and they are better than before, but not as loose as the 1&2 pistons. I will get another two sets of new rings on Monday and have another go at cylinder assembly.
I really would like this engine to last another 100000km before I have to touch it again, so I am not sure if I am doing the right things with the engine- I sanded the scores off the piston skirts, carefully to remove any high spots, and localised the sanding to minimise dimension changes of the pistons skirt. I have since read on the net that cleaning out ring lands with a broken ring is too rough and may cause ring land damage on all three sides of the land surface. I am considering buying a new set of pistons, but after spending $400 so far on gaskets, o rings and piston rings, the piggy bank is dry. I bought a trailer to tow with the GT, so the piggy bank is extra dry now too.
Does anyone have experience rebuilding the old air cooled Kwaka motors? Would you re-use the pistons? Could you suggest a better method of cleaning the pistons in-situ? Thanks for any tips. I have had a lot of dramas with this rebuild, which wasn't supposed to be a rebuild.....I would like the bike to run well when I am finished and last a long time- the effort required deserves it! I reckon it will take two whole weeks of spare time to do this, which because I am quiet at work at the moment (cold weather) equates to around 80 hours of work....(imagine paying a bike shop $66 or so per hour for that!)
TIA!
It has been quite a learning curve- the cleaning processes alone have taken days and I am suffering really buggered, sore and cut up hands.
What I discovered when I disassembled the engine was that two rings had frozen in their pistons (both middle rings on pistons 3 & 4) and that the piston skirts had scraped on the bores, leaving some alloy behind.
I sanded the alloy off the cast iron bores and along with the hone I had done professionally, the bores look A1- and still on original specs.
The 3 & 4 pistons however have been a bitch to clean the ring lands on- my first attempt I thought was ok, but when I tried to install the barrells, both 2nd rings broke. (they were new and cost $80) I have since spent another 2.5 hours cleaning the ring lands out with broken rings and they are better than before, but not as loose as the 1&2 pistons. I will get another two sets of new rings on Monday and have another go at cylinder assembly.
I really would like this engine to last another 100000km before I have to touch it again, so I am not sure if I am doing the right things with the engine- I sanded the scores off the piston skirts, carefully to remove any high spots, and localised the sanding to minimise dimension changes of the pistons skirt. I have since read on the net that cleaning out ring lands with a broken ring is too rough and may cause ring land damage on all three sides of the land surface. I am considering buying a new set of pistons, but after spending $400 so far on gaskets, o rings and piston rings, the piggy bank is dry. I bought a trailer to tow with the GT, so the piggy bank is extra dry now too.
Does anyone have experience rebuilding the old air cooled Kwaka motors? Would you re-use the pistons? Could you suggest a better method of cleaning the pistons in-situ? Thanks for any tips. I have had a lot of dramas with this rebuild, which wasn't supposed to be a rebuild.....I would like the bike to run well when I am finished and last a long time- the effort required deserves it! I reckon it will take two whole weeks of spare time to do this, which because I am quiet at work at the moment (cold weather) equates to around 80 hours of work....(imagine paying a bike shop $66 or so per hour for that!)
TIA!
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