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Bonnie T140 #784687 09/18/19 3:11 pm
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My bonnie has had an issue with smoking on occasion, worse on left side.
I was fitting a new throttle cable yesterday and did so with it on sidestand, it sat on the sidestand overnight too.
I unscrewed the top off each carb and noticed the piston of the left one is dirtier than the right one. I then put my finfer down the barrel and it had oil in it, enough to wipe on my finger.
Upon starting it smoked clouds out the left side and a little out the right..(no link pipe on exhausts).
Valve guide leak occurs to me, any other ways oil could get into the bores/intakes when at rest and it smokes running?
Thanks

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Re: Bonnie T140 [Re: RGM] #784692 09/18/19 4:17 pm
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...hello; one thing to consider is that if you still have a strong pull of the engine; is not a rings problem so could be the guides but in my case I am having plenty of oil consumption but no smoke...
I have a rotary pump (and the external oil is fitted with a hose directly to the crankshaft); so the oil circulates fast in the system and sometimes I have found too much ¿? oil (700cc!) in the primary.
i do not have an explanation for that.

Re: Bonnie T140 [Re: RGM] #784745 09/19/19 2:51 am
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Hi RGM, What year is your bike?

Highly unlikely to be valve guides. Even very worn guides give very little oil consumption or smoke. There is only a tiny amount of oil in rocker boxes. Most runs straight down side of box.

I have '73 tiger. I leave in on side stand overnight often. I used to always leave on side stand even for weeks, it never ever smokes on start up or running. Valve guides are very worn. Rings have 32k miles from new, but doesn't use oil or smoke ever. I often leave bike running on side of road for quick restroom break in the bushes. It never ever smokes.

If the oil pump is not putting oil back to frame properly that can be a problem. If pump is allowing gravity to leak oil by pump into sump that is also a problem. Both can happen. Leaking into sump, & then weak pump not bringing it back to frame efficiently.

If you ride the bike say 15 miles. Bring it in garage. Let it cool 30-60 min, then drain motor sump, how much comes out? Drain it into an 1 qt or ltr oil bottle with side cut out. Then pour into clear baby bottle marked in cc. Do this test a few times over a few days to reduce chance of errors. Record the amount.

If you have too much oil in motor sump, no rings will control the oil & smoke.

There are a few things that can go wrong with pump to cause this. Don't jump to replacing pump. Do some diagnosis first so you get correct repair first time.

If sump oil levels are good & pump tests good you'll need to do top end tear down & repair.
Don


1973 Tiger 750
Re: Bonnie T140 [Re: TR7RVMan] #784756 09/19/19 8:03 am
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Hi,
The bike is a 1979. I have previously looked into wet sumping/pump not scavenging enough oil and I do not believe it is an issue. I can't recall the measures I drained after various runs but it was about what I was told is fine....less than a cup full anyway.
I feel a steer to my problem must be the oil in the left carb body and intake when I wiggled my finger in with the piston out of the body doing the throttle cables the other day. Nice clean engine oil it was (it has clean oil in the frame)
Somehow that oil has got there? if there is oil in the carb the instake/bore I guess was even worse.
Normally when started from cold it does not smoke, it starts smoking after 5 or 6 miles and can be bad enough to have people telling me my bike is smoking!
It did this on the way to my last mot...by the time I started it for the mot tester it was clean again! passed its test then smoked on the way home.
Could it collect too much oil in the rocker boxes?
Many have suggested rings to me, but I can't understand how that would result in clean oil in the intake/carb and probably smoke awful from cold too.

Last edited by RGM; 09/19/19 8:05 am.
Re: Bonnie T140 [Re: RGM] #784804 09/19/19 10:30 pm
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I think the previous post is your problem too, T140 loose head studs.
Regards Peter


'74 T140V,'83 XR1000, C&J FLATTRACKER T140,
Re: Bonnie T140 [Re: RGM] #784828 09/20/19 6:15 am
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Hi RGM, Does the breather still go to the air box on your bike?

What happens if you retorque head? Worth a try. Always check valve clearance after head torque.
Don


1973 Tiger 750
Re: Bonnie T140 [Re: RGM] #784847 09/20/19 2:28 pm
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...is not good to retorque heads over and over due to you break the "sealing" made by the carbon etc
You only need to retorque after 10 kms or so then another at about 200kms and at 750kms; nothing more.

Re: Bonnie T140 [Re: reverb] #784851 09/20/19 3:31 pm
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Originally Posted by reverb
...is not good to retorque heads over and over due to you brake the "sealing" made by the carbon etc.



That sounds like nonsense.


Amateur Loctite enthusiast.
Re: Bonnie T140 [Re: RGM] #784867 09/20/19 5:56 pm
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Why?
Do you think that there s no any residue formed between the head and the gasket?

Re: Bonnie T140 [Re: RGM] #784902 09/21/19 12:32 am
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Hi All, So.... if the carbon is sealing would we have a leak?

I've never even once seen retorquing head cause a leak. I've seen many leak from not retorquing. I've even seen a few stop leaking after retorque.

I generally retorque mine before every valve adjustment.
Don


1973 Tiger 750
Re: Bonnie T140 [Re: RGM] #784920 09/21/19 3:14 am
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...the manuals say that you only need those 3 re torques. If those heads are in constant need of re torquing may be the bolts etc are too stretched. I am talking about blown gaskets not oil leaking.

Re: Bonnie T140 [Re: TR7RVMan] #784995 09/21/19 9:24 pm
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I've cured leaking head gaskets (not on Triumphs but BSAs) with tightening-down head fasteners (I can't, to be honest, call it re-torquing because no torque wrench was involved - just me, as a naive 18 - 19 - 20 year old brutally tightening whatever I could in the hope it did the trick - and it did!)

I honestly can't see any reason why re-torquing could possible do any harm. If composite gaskets need repeated re-torquing (which is what I found when using one on my TR7), it goes to show how inadequate those gaskets are, I'd have thought. I will only use solid copper gaskets in future. Only reason I used the composite one was foolish belief in what I read on internet forums!


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Re: Bonnie T140 [Re: TR7RVMan] #785877 09/30/19 12:36 pm
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Originally Posted by TR7RVMan
Hi RGM, Does the breather still go to the air box on your bike?

What happens if you retorque head? Worth a try. Always check valve clearance after head torque.
Don

Don,
Thanks for your interest. I am not experienced with the triumph it being my fist old British Bike, though had plenty of motorcycles. I do not want to go careering down the wrong road in trying to sort this issue out which is why I have not got started further and sat it at the back of my garage in disgrace!

To answer your question, if you mean the breather from the left side of casing to right side of airbox, yes it is fitted and it is oil free inside the airbox.
I will strip the tank/rocker box covers sometime and retorque the head.

I do think the fact I could wipe oil onto my finger from inside left carb (when the top and carb piston were removed) and by wiggling it into the inlet duct towards the left cylinder means oil has got there from somewhere?


Last edited by RGM; 09/30/19 1:18 pm.
Re: Bonnie T140 [Re: RGM] #785880 09/30/19 1:32 pm
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Do you have the composite head gasket? There are different torque procedures for composite vs.copper.

Have you done a compression test?

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Bonnie T140 [Re: JubeePrince] #785900 09/30/19 6:18 pm
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I personally have not had head off and very little history with it, but it looks like copper to me unless the composite one has a copper edge.

I compression tested it when the problem was noticed and both cylinders importantly were the same and decent......my gauge always reads a bit low it seems, I think the long flexible hose it has may have a little give in it.

Re: Bonnie T140 [Re: RGM] #785905 09/30/19 7:13 pm
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Hi RGM, Condensed fuel & blow by can leave an oily residue. I might hook a hose to breather at chain case & zip tie it along rear fender replicating the old version breather. Clean carb slide with some spray & ride a few hundred miles & see what it does. Clean breathe exits & hose out also so residual oil in hose etc doesn't get sucked into carb.

I don't have personal experience if your year bike has a tendency to get slides oily or not.

I know from much personal observation that weepy head gaskets look oily even on older 650s & even flat head lawn mower motors with virtually no oil feed in the area so it has to be from the combustion gases condensing. I know from experience from work, blow by gases condensate to oily residue.

This is why I suggest the breather by pass experiment. On the early system there is not vent at top of exhaust rocker box. The frame vent near head tube, was T'd into breather hose near backbone, & then it ran along side rear fender exiting at bottom back of rear fender. Be advised when braking hard oil runs up the backbone & some will trickle down breather hose into exhaust rocker box, but I doubt you need to use a T for this test.

Very little oil gets to top of valve guides. If guides were replaced & any scoring happened in head bore, that certainly will drain oil into intake port. Run motor some time with valve covers off. You'll see what I mean about how little oil gets to valve stem. Hardly a drop will even come out the valve cover opening. Most all the oil runs out rocker shaft & straight down side of box. Almost no oil runs down bottom of rocker arm. A little tries to run down top of arm, but flies off before valve stem. No wonder the adjuster screws wear so fast. If you think oil is leaking by guide bore in head, remove carb & valve cover. Close valve, clean port. Carefully squirt oil in around valve stem at bottom spring cup & observe for leaks around valve guide in port.
Don


1973 Tiger 750
Re: Bonnie T140 [Re: TR7RVMan] #785985 10/01/19 4:32 pm
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Thanks Don,
I will wheel her out from the naughty step and look at her more thoroughly over this winter. I still feel it was proper oil I wiped on my finger from the carb and intake on the left and it smoked on start up like proper oil too! I do wonder if there is a scored valve guide bore in the head.

Re: Bonnie T140 [Re: RGM] #785990 10/01/19 5:04 pm
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If you leave a bike on the side stand, oil collects on the left hand valves. Leave it long enough and the first time you start it up, loads of oil drops into the cylinder

You realise that you don't remove the rocker boxes to retorque?

Re: Bonnie T140 [Re: AngloBike] #786009 10/01/19 7:24 pm
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Ah, having looked at the manual I now see the rocker boxes do not need removing to re-torque, so will lift tank off and do that. so the extra smoke on start up the other day could have been due to being on sidestand for some days. It is not normally left on side stand.
I still have the general fact it smokes awful once warmed up, usually left cylinder i think....but it is a bit on and off!

Re: Bonnie T140 [Re: RGM] #786019 10/01/19 8:25 pm
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You don't need to remove the rockerboxes to torque the head fasteners but you will need to make (or get made) a special tool to do this. And I don;t mean the daft hex bar / hex head adapter that's commonly sold - these fit down the 5/16" rockerbox bolt holes and into the hex sockets of the sleeve nuts nicely, but you won;t get a torque wrench to fit on the hex head. There is nowhere near enough room between them and the frame to fit any torque wrench with a socket fitted.

What you need is a flat ring spanner with a nut welded 3" or 4" out, on which you can place your torque wrench's socket. You then need to work out the torque in inch pounds and calculate how many inch pounds you're getting with your extra 3 or 4 inches. A palaver, but the only way to do it, unless people on here know of an extremely shallow torque wrench and extremely shallow sockets.


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Re: Bonnie T140 [Re: RGM] #786036 10/01/19 11:02 pm
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Hello Tigernuts; I have a better solution (and tool) You need an hex bar like an Allen key and a 3/8 socket (for a 3/8 torque wrench)
Have (cut) 2 pieces of the hex bar; one short; very short; the other a bit longer. Check the distance from the frame tube on top first, then do the cut.
Just that.

I used in both 79 engines; one fitted in the original frame and the other fitted in a T120 frame.

Re: Bonnie T140 [Re: reverb] #786098 10/02/19 9:35 pm
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OK, maybe with a 3/8" drive torque wrench you can fit it under the frame? I have a 1/2" drive wrench and there's no way that will anywhere near fit.


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Re: Bonnie T140 [Re: Tigernuts] #786103 10/02/19 10:22 pm
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Originally Posted by Tigernuts
OK, maybe with a 3/8" drive torque wrench you can fit it under the frame?


Yes, 3/8" drive does...just.
Getting the socket on the cut-down length of Allen key is the awkward part so that has to be as short as possible although grinding the socket down would allow more clearance, the rear RH rocker box fastener is the tightest, the others and the two central head sleeve nuts aren't a problem.

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Last edited by L.A.B.; 10/02/19 10:46 pm.
Re: Bonnie T140 [Re: RGM] #786125 10/03/19 2:56 am
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Hi, I have a 3/8 12 point torque adapter I made from a wrench 6" long so you cut torque in half. This allows reaching all nuts with tank in place. Use a cut short piece of 3/8 hex from allen wrench.

Rub is you need an accurate torque wrench as the center nuts are 8# & inside rocker box nuts are 9# with 6" torque adaptor. I use normal socket on the outer 4 hex nuts so 18#. My small torque wrench only goes to 25#. Snap-on dial type. Inside is a bending beam. They are most accurate Snap-on sells.

I would never use my larger torque wrenches that max at 60 or 130# on even 18# as they are not that sensitive in the lower ranges. Click type tend to be least accurate in lower range of rating. These generally have a coil spring that gets compressed, then clicks out of detent when pressure is overcome at torque setting.

Digital is no more accurate in & of itself. It's just a bending beam with electronic reading that may beep at you so you don't have to look at it. So digital are coil spring with digital scale also.

Still in practice head bolts/nuts are fairly forgiving. Rod nuts, no so much. You want an accurate wrench.

The smaller bending beam with a long pointer can be much more accurate than click type even though a fraction of the cost.

Problem is with bending beam & dial type you have to actually read it & stop at correct reading while wrench is still moving. So you need direct straight on view.

At work we always use click type for head bolts, wheels, axle nuts, steering wheels. But for the smaller things like valve bodies, injection pump parts we use dial type.

In every case you need an even steady pull. No quick jerking, no really, really slow. Unless the nut was rather loose with little stiction on nut(bolt) if you put torque wrench on & just turn it, it will often read torque, but is actually too loose. That's why it's best to back off fastener a little & then come up on torque again. A hand or thumb on the torque wrench shown on center head nuts is a good idea to stabilize wrench during pull. Gives more accurate reading.

Don


1973 Tiger 750
Re: Bonnie T140 [Re: RGM] #786138 10/03/19 9:49 am
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Well I'll stick with my two 1/2" square drive torque wrenches (one is up to 30lb/ft the other up to 120). The 3" (or 4" or 6") extensions do the job. Those 'adapters' sold on eBay etc should come with a note that they need a 3/8" wrench and cut down socket etc!


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