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Discussion Starter · #1 ·
Hi all, decided to delve into the engine of the T140 today and got a bit of a surprise at the condition. It’s a US import and was solid but tatty so was expecting a full engine rebuild but not sure now. Pistons are +060” by the reference number. Any ideas what I should check next ? Not sure how to proceed. Opinions invited.
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Discussion Starter · #3 ·
Hi thanks for the reply. I haven’t cleaned them that’s what the surprise was. All the fasteners undid easily there was oul around the head and the pistons were gleaming. I presume someone has given it the once over recently. But I’ll check the bores like you said. Is there anyway to check the bottom end without splitting the cases.
 

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Discussion Starter · #5 ·
Yes I’ll get the DTI out. Not sure my vice is big enough to hold the engine but I may be able to screw it to the bench. Im going to take the side covers off check the clutch oil pump etc. is there anything specifically to check or is it just common sense checks.
 

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Discussion Starter · #9 ·
Mmm I was hoping to avoid splitting the cases but maybe that was wishful thinking as I don’t have any history on the bike.
 

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Discussion Starter · #11 ·
That’s pretty full of crud. I’ll have to give it the full strip. Did the crank need regrinding and would new Conrad’s be needed. I’ll replace the bearings while I’m there.
 

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Discussion Starter · #17 ·
Thanks for all the input guys. I didn’t ride the bike before strip down and it only ran briefly due to carbs etc. so for piece of mind I’m going to do a full strip down. I’ll be seeking advice as I go along so be prepared for more questions.
 

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Discussion Starter · #18 ·
Well took the barrels off this morning and not good. It’s already on +060” and the left pot has some bad scoring in it.
 

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Discussion Starter · #23 ·
I’ve continued the strip down today but have come to a stop as can’t get the clutch basket out or the pinion gear off so will have to get the tools. My opinion on the engine is it has been well maintained during its life. All fasteners are in good condition and everything has undone without drama. It will all come down to how worn things are I suppose.
 

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Discussion Starter · #26 ·
If you don't have the special tool you don't need to remove the pinion before splitting the crank cases. It will follow the crank shaft through the crank case. Once removed you can remove it with a more traditional puller. Be careful of the crank shaft end on that side- it must never be bashed!! If it gets deformed, oil supply to the crank will leak past the lip seal, which this shaft rotates against.
You definitely need the tool for the clutch basket. You will also need a small hub puller to get the primary drive sprocket and cam shaft gears off.
Thanks for that I’ve ordered the clutch tool and a small puller.
 

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Discussion Starter · #27 ·
Yes the engine looks very clean and well looked after. I’m going ahead with the full strip down hope fully things will be good inside.
 

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Discussion Starter · #31 ·
Hi Yaswas,
the photo’s of the pistons is telling, if you zoom in you can see grit or something embedded in the soft aluminium of the piston; would wager that the embedded material aligns with the deep scores on the barrels.
This begs the question, do you know if the frame has been shotblasted and repainted?
It is almost impossible to keep the shot blasting material out of the integrated oil tank and once in, almost impossible to clear it all out, it only takes a few grains circulating in the oil to destroy an engine.
The traditional safeguard against this is to fit a full flow paper oil filter in the base of the frames integrated oil tank, colloquially these are referred to as "Charlies" style filters.
I would allow funds for this, if not already fitted and even if you already have a return line cartridge filter.
You will need to check the oil pump for scoring damage. Hopefully, the sludge trap will have protected the crankshaft from similar damage.

Those pistons have the strange surface finish on the sides that is on the top, it is most unusual.

regards
Peg.
Don’t think the frame had been blasted. It looked pretty original, I have repainted it now but used a wire wheel to strip the paint as I didn’t want to blast it for obvious reasons. I’m going to fit an external cartridge filter. I’ll have a look at the oil pump but may stump up for a new one as it looks like the original so presume it will be worn. Don’t know what’s gone on with the pistons but doesn’t really matter as it’s going to get new ones and barrels.
 

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Discussion Starter · #32 ·
Hi Yazwaz, It’s hard when you cannot fully evaluate a bike new to you.
I find if I can put at least 50 miles on it I have a good idea of obvious faults.
These motors are certainly full of surprises!
At least you expected to do overhaul so your expectations were realistic.
Finally had a break in the rain here. Nice sunny day yesterday. Balmy 55f!
Was thinking how comfortable & nice the T140 type bikes ride. The 5 speed, brakes controls just work so nice.
Dry frame is excellent bike, don’t get me wrong, but to my body the later bike is a little nicer to ride.
Don
Yes I’m looking forward to riding it when it’s done. That’s why I’m going to make it as good as I can.
 

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Discussion Starter · #36 ·
The external oil filter will filter the return oil. So if you've got muck in the frame it will have to pass through the engine before being filtered.
An in frame filter will filter the supply oil. So, in your case, unless you are absolutely sure that the frame is clean, this may be a better option.
You may be swaying me it makes sense to filter before it enters the engine and also looks more stock. I’ll be giving the frame a good clean as well.
 

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Discussion Starter · #38 ·
I would bet those pistons have been sand blasted. A lot of the grit has been left around the engine and caused all the damage. The state of the shell bearings should be revealing. What is your location in the UK ?
We’ll have to see what awaits. I’m in Bolton near Manchester.
 

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Discussion Starter · #40 ·
I’ll change all the bearings while I’m there anyway. I would have thought even the daftest person would have sandblasted the pistons out of the bike and cleaned them. The other bore is in good condition so hopefully that’s not the problem but we’ll see. This could be getting expensive.
 

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Discussion Starter · #43 ·
Well hopefully I’ll do it it right this time. On a side note are Conrods usually changed on a rebuild. I’m presuming they are the original ones. And what’s required for the cylinder head.
 
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