GT550 engine rebuild questions

[bonester]

Yup 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!

[Felix]

I don't think I'd bother with new pistons unless you were going to do a rebore, and of course wanted to go to the effort of REALLY stripping it down. If there aren't any obvious problems, I don't think I'd get too fussy. Ideally maybe you wouldn't use a broken ring to clean the lands, but I bet it happens a lot.

At the end of the day, it is probably going to end up a lot better than when you started, so why worry?

Knew a mechanic who specialised in fixing old cars for people with no money - the things he could get away with...it is amazing how long a "stuffed" engine can last with less than perfect repairs and simply keeping enough oil and water in the damn things (although the water may not apply to your GT )

[bonester]

Thanks Felix. Maybe I am being a little too fussy for an old GT. I do however want it to be 100% reliable like it has been in the past- planning another run to Newcastle in August- this time two up towing a medium sized trailer.
I have since thought that the wreckers might have 2 good second hand pistons, and that I will measure the skirts before making any decision too.

[Felix]

Well it was running ok with seized rings before wasn't it?

I'd stick with the pistons you have, otherwise you need to start fudging with bearings, pins and crap...I reckon if you are going to start down that path then really you need to buy brand new pistons, rings and rebore the thing and balance it all....$$$$ can you hear the money burning???

Bung it together with a bit of SBR* and away you go.






* She'll Be Right

[bonester]

Well it was running ok with seized rings before wasn't it?

Yup it has always run like a dream (after I tuned it when I got it) Done 12000 trouble free kms, apart from the oil leaks that shit me.
I think I'll look into some of that SBR mate! Cheers!

[Neka79]

i was gunna say..
"why bother?? throw it out"

[bonester]

I can't see your Blade still running in 2020 (when it 20 years old like my GT) without some work, and yes it will be a dinosaur then too, maybe with some appeal for someone.

[Neka79]

I can't see your Blade still running in 2020 (when it 20 years old like my GT) without some work, and yes it will be a dinosaur then too, maybe with some appeal for someone.

mate it will be lucky to make it to 2007!!

[Felix]

mate it will be lucky to make it to 2007!!

I doubt your licence will!

[Neka79]

mate it will be lucky to make it to 2007!!

I doubt your licence will!

yea of course it will...i get it back in december...im ok too keep it for at least 3 months.,..