Can any one tell me what these pistons are from?

Bikemike · Post by **Bikemike** » Sat Jun 23, 2007 8:51 pm

Pulled the barrels off the garden project today, What a result, the engine is in great nick inside, no corrosion and very little wear.
It has been tuned by Graham file and is running different pistons, does anyone recognise them?

Sorry about the rubbish photos, I can try and get better ones if that helps.
Many thanks,
Mike

mr_bungholeo · Post by **mr_bungholeo** » Sat Jun 23, 2007 8:57 pm

look like tz pistons to me...26j?

mgtkr1 · Post by **mgtkr1** » Sat Jun 23, 2007 10:25 pm

very lucky find! cases look a work of art, piston definitly arent 26j, but look like tz of some sort, possibly 4dp? beware of the barrels been shorter as if there 4dp they will have been. you will have to stick to whatever pistons are in there currently if they've been shortened as std ones will certainly touch the head! the motor must have cost serious money to build as graham aint cheap and is very proffesional, f250 spec is well over a grand for the full monty so if yours has little wear youve done very well!!

mgtkr1 · Post by **mgtkr1** » Sat Jun 23, 2007 10:38 pm

could you post a pic of the head please m8?

Red Devil 777 · Post by **Red Devil 777** » Sat Jun 23, 2007 10:43 pm

I can't understand just leaving that to rot, you've got to be slightly deranged to do that.

Absolute heathens some people, should be tarred feathered and made to drive Triumph Dolomites (maroon ones eh, Lee)

mgtkr1 · Post by **mgtkr1** » Sat Jun 23, 2007 11:13 pm

i agree, it looks as though it barely been run jugding by the piston crowns, gaskets and lack of marks on pistons! wonder how it ended up rotting in a garden/shed? hope what i suspect happend didnt? cant see any other reason though why someone would spend a grand on a engine tune, 200 on topend overhaul then just leave it, also looks like it was intended for race use rather than a ''mid life crisis/loss of intrest as it wasnt just a plain old rebuild.

Bikemike · Post by **Bikemike** » Sun Jun 24, 2007 9:32 pm

The owner used to race it, had just had the engine tuned in 1997 (£600- I have the receipts) but when he started a family he ended the racing and put it back on the road.
He didn't use it much and put in in the garage, when he moved there wasn't space so thats how it ended up outside.
It wasn't wilfull neglect, just a combination of circumstances. I think he was sad to see it go, he is a real enthusiast who knew his stuff but his business commitments meant he couldn't do anything with it. I'm going to keep in touch and let him know how the restoration goes.

Mike

Bikemike · Post by **Bikemike** » Sun Jun 24, 2007 9:33 pm

More poor photo's-

The quality of the porting is superb, a credit to Graham, you can certainly see why he has such a good reputation.
Its just a shame the rest of the bike is such a mess.........

Mike

mj43 · Post by **mj43** » Mon Jun 25, 2007 1:41 pm

They look like 3TC or 3AK
Measure the height of the barrel if it is about 89mm then they have been shortened and they are deffo 3TC/3AK

Stock barrel is 90.6 ish (can't remember exact dimensions)

If they have been shortened examine the back mounting lugs carefully for cracks - the barrels fail at that point.

Flowed cases as well.

mgtkr1 · Post by **mgtkr1** » Tue Jun 26, 2007 2:28 am

even with poor pics, you can see the quality of grahams fair hand as you say, bet its a real flyer particularly in the mid range as graham is famous for his logical thinking, drive is much better than 12hp at 8000rpm-88hp at9000rpm!! probably why it was used on the road as graham file engines can be ridden to the shops as well as anihilate all else at the race track, bike mike that is one lucky find! lucky bugger

Bikemike · Post by **Bikemike** » Wed Jun 27, 2007 7:42 pm

Measured the barrels today, 89mm as you thought Mark.

I guess that means 3tc or 3ak pistons. Are these still available readily?
Do Yamaha still support the tz?
The ones in there look fine but I am bound to need some sooner or later.

There are no visible cracks on the lugs but how on earth do you torque the nuts up? I could only just get a spanner on them, let alone a socket.

Drained the gearbox oil today, it came out looking brand new

Clutch is seized though, any tips on freeing it off?

Mike

mgtkr1 · Post by **mgtkr1** » Wed Jun 27, 2007 8:23 pm

clutch is held on the shaft by a large(ish) circlip, once you get it off undo the 5 screws that holds the plates in a pack, the ''star'' shaped alloy is very prone to breaking if care isnt considered, undo gradually as you would a cylinder head. place upside down in your hand and it should drop out(set of plates) then soak in petrol and carefully seperate the plates using a screwdriver, voila, job done! the base nuts are a pita needing certain spanners of 12mm, any will do, modify a spare one using a grinder, as long as it fits on and off, who cares! as far as i know tourqueing base nuts(front ones) is not possible? most importantly is REMEMBER the diffrence in height coz like mark has already said theres 2mm between yours and std meaning the accidental use of a std or std dimension piston will be catastrophic!

mr_bungholeo · Post by **mr_bungholeo** » Wed Jun 27, 2007 8:26 pm

KABLAMO!!!!!