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Discussion Starter · #1 ·
Hoping for some advice regarding my T140 I've recently aquired.
I did a compression check and got identical readings on both cylinders (warm) of 155 psi. I then put a few squirts of oil from my oil can and got readings of 170 psi, does that mean the bores are worn?
Sometimes (but not always) she smokes (more from the left hand cylinder than the right) when I blip the throttle, white/grey smoke, also black, I can sometimes get quite a cloud especially once she is hot. I haven't owned it long enough to tell what the oil consumption is like. The previous owner said the bike sat unused for the previous year and only shows about 150 mile on the clock since last MOT about 2 years ago.
What do you think, should I just ride the hell out of it?
Thanks
Stewart
 

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I would ride it for a while and see if the smoking abates from bedding in after sitting. It may need a light honing and new rings, maybe valves and/or guides; hard to say.

(I would ride it till it blows up)
 

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I'd have to go with GPZ. Run it a bit and see if the rings do seed in. If you still get the big compression change with oil in the cylinder you'll need to think about a repair. If that is, in fact, the case, I would just add that it may be better done sooner than later. If things are only just slightly worn then a hone and ring set is a lot cheaper than a re-bore with new pistons, pins and rings etc. because the cylinder walls are now scored or whatever.
 

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stewart42,

Just run it for awhile. Mine was good enough to fog the
driveway down for the first couple of days. And like Paul
stated the rings rebedded down, smoke gone.

Oh, and welcome to the forum.

Pookybear
 

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Go for a ride with a mate behind you on another bike or in a car.

If it smokes while riding on flat road at constant throttle, it will most likely be rings.
Then, find a decent hill and decellerate down it for a few hunderd metres, then accelerate. If it smokes heavily when you accelerate, it will probably be valve stems and guides worn.

If you're going to take the head and cylinders off to do a hone and replace rings, check the valves and guides at the same time, and fix any issues. It will save you ripping the head off later if the hone doesn't fix the problem.

If you're going to keep riding it, make sure to check the oil level regularly.
 

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That sounds like good compression...the smoke could be from carb misadjustment.You haven't said how it runs ,idles etc.if it runs well I would just ride the hell out of it until it doesn't
 

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Discussion Starter · #7 ·
Those are the kind of answers I like..... The bike runs really well, idles great and starts first kick. It "pinks" quite badly if I lug it so I try not to, the plugs are very dark (black) but dry so maybe it's a bit too rich?
I always read about adding oil when doing the compression check but they never say by how much it will increase, does 15 psi even point to worn rings? Also what psi should a T140 in good condition give?
I'll keep an eye on the oil level and see if I can get the summer out of it.
Thanks for all the help
Stewart
 

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I take it that by mentioning MOT in your first post that you are UK based?

What petrol are you using? I have taken to putting 'super unleaded' in mine, 99 octane. That has helped a lot with reducing pinking. It is now less likely to happen than when I was able to run it on four star.

If you have worn inlet valve guides oil will be drawn down the valve stems into the mixture and burning oil will make the plugs black and sooty and also cause pinking. But if that is the case you will soon notice the oil consumption.
 

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I always read about adding oil when doing the compression check
Stewart
Odd,

Ihave always used this but only on a cylinder that has a
low compression check numbers to start. You add oil
to seal the rings up in the cylinder with the low number.

All its for is to let you know if the compression number goes
up it rings. If the compression number stays the same,
valve and seats or a head gasket is the problem.

Pookybear
 
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