Im new to triumph I just bought my first it is a 1965 Bonneville T120R twins chopper I recently pulled the head off and found it had pistons that read 1.50 on them and I think they are 11.5.1 compression they are a little sloppy in the jugs but it doesnt smoke and doesnt sound bad when running but you can clang the pistons back and forth against the jug walls but the pistons and jugs are not damaged in any ways. My question is . I quess this is seriouslly overbored correct ? Is there a place to buy sleeves for this or should I just purchase a new jug and pistons? And do any of you out there have any of this or any spare parts for this motor. Thanks for your time.
1.50 is overbore in mm. Equivalent to about .060", iirc.
That's getting kinda thin, most people consider +.060 the very max.
I've seen pistons availible for stock cylinders bored +.080, but don't know anybody who's actually tried it.
Apparently it's not a real good idea for a reliable street bike.
If the bores mike beyond tolerance for new +.060 pistons and or rings, put 'em on the shelf. The way prices are going, they may be worth their weight in gold on ebay someday.
You could probably bolt on a brand new 750 'big bore' kit for not much more $ than resleeving and replacing the stock components would cost ....
Dead right there Oily. So 650, you have the choice, there are new 650 cylinders out there, also good used ones or go for a 750 kit.
When my crank broke and wrecked my std bores I went for a MORGO 750 kit. It cost me £260 ($470) but was complete with pistons, rings and head gasket. Instruction and ready to bolt on.
I am still running it in (700 miles) at present, but it feels and sounds good. Ther must be an agent in America? Roy
On 2005-05-30 14:59, DAGAD wrote:
Dead right there Oily. So 650, you have the choice, there are new 650 cylinders out there, also good used ones or go for a 750 kit.
When my crank broke and wrecked my std bores I went for a MORGO 750 kit. It cost me £260 ($470) but was complete with pistons, rings and head gasket. Instruction and ready to bolt on.
I am still running it in (700 miles) at present, but it feels and sounds good. Ther must be an agent in America? Roy
hi,
i fitted the 750 big bore kit with lower 8.5 to 1 compression pistons.it produces much more bottom end power,and no additional vibration.mine came from tri_supply in england.he posts worldwide.its a bit heavy though,cheers.geoff :hammer: :hammer:
Hi Shortys, not in England but maybe over there. Our dealers have to buy min 3 sets at a time and I know at least 2 dealers with stock, who also ship world wide. Roy
I went for a MORGO 750 kit. It cost me £260 ($470) but was complete with pistons, rings and head gasket. Instruction and ready to bolt on.
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