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#524605 - 01/25/14 3:37 am T 120 bonnie air coming out of carby  
Joined: Mar 2013
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Michael Offline
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Australia
I have for the first time since I started building my bike from scratch heard it running, it seems to be only running on the Right side and the exhaust seems to be coming out of the left carb or at least a lot of air, I need a little advice on what could be causing this, Thanks


Bucko
1966/68 T120 Bonnie
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#524615 - 01/25/14 5:52 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Jack Russell Offline
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Melbourne, Australia
Dodgy intake valve perhaps.
Cheers
Jack


Cheers
Jack Russell
#524617 - 01/25/14 6:03 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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triton thrasher Online content
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Valve clearance adjusted very wrongly (first thing to check), or pushrod end cup displaced from rocker or from cam follower.

Or even the exhaust valve failing to open, for similar reasons to above.

Some gas is always blown back at low rpm, but shouldn't be "a lot." Is there a spark and fuel present on the non-firing cylinder.


Amateur Loctite enthusiast.
#524631 - 01/25/14 10:25 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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John Healy Online content
John Healy  Online Content



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Quote:
Or even the exhaust valve failing to open,


DITTO... what TT said...

If you have compression on both cylinders a pushrod might not be in place.
Remove the rocker caps and inspect the valve action. You cold have an exhaust pushrod that is not in place.


#524676 - 01/25/14 2:09 pm Re: T 120 bonnie air coming out of carby [Re: Michael]  
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UK Berks
have you checked for a spark on that cylinder?

#524700 - 01/25/14 5:27 pm Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Sounds like a pushrod has jumped off

#524717 - 01/25/14 6:57 pm Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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Australia
Righto I'll have a look today, come to think of it, didn't check the spark on that side (idiot) so I'll check that first. Then off with the rockers and check.
could it be the timing gears at all?? seeing as right side is working fine.
Thanks.


Bucko
1966/68 T120 Bonnie
#524754 - 01/25/14 10:08 pm Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Pete R - R.I.P. Offline
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If the cam timing is right,you'll have 0.140" intake valve lift at TDC.If it's out by one tooth,that lift will change by 0.055".
If you have a 1968 exhaust cam,the lift will be the same at TDC (0.140").If you have a '66 exhaust cam,it will be less.

This would of course affect both cylinders,not just one.

#524756 - 01/25/14 10:17 pm Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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Sorry I say 1966 model loosely, the cams are 3134's barrels and pistons are 750cc big bore kit with venolia pistons and head is 1963 modified for spigot mount carbs and push on pipes ect.. So as you can see its a bitsa.


Bucko
1966/68 T120 Bonnie
#524787 - 01/26/14 1:06 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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Michael  Offline
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Australia
Just pulled the tappet covers off, the inlet rocker adjuster was knocking on the cap so put a bigger o ring on and seems to work fine now, there doesn't seem to be oil pumping now, I'll pull off the pipes and see if they are on the right way.


Bucko
1966/68 T120 Bonnie
#524791 - 01/26/14 2:00 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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I bit of a silly one, on the oil junction block is the rear one into the engine and the forward one out with the flow the manual says this in a way but not quite sure.


Bucko
1966/68 T120 Bonnie
#524793 - 01/26/14 2:05 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Pete R - R.I.P. Offline
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Are you talking about return oil pumping back to the tank and rockers?Don't expect that until the engine is running.

The front oil hose at the pump is the feed hose that supplies oil from the tank.

To see if oil is pumping,you can remove the plug at the lower front of the timing case.Kick the engine over a few times and see if oil is pumping out,then replace the plug.

#524800 - 01/26/14 3:17 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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Australia
OK I've done all that to no avail, the bike does run but I'm hesitant to do so without knowing for sure the oil is pumping, does there need to be oil in the system ie primed? before it will pump??


Bucko
1966/68 T120 Bonnie
#524802 - 01/26/14 3:42 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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kommando Online content
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Scotland
Quote:
does there need to be oil in the system ie primed? before it will pump??


No but on a fresh rebuild re-primed fully it quickly shows if there is a problem, as it is you are now in the dark as it can take some time for the oil to appear, so prime it now and remove the doubt.

#524804 - 01/26/14 3:46 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Stuart Online content
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Hi Bucko,

This works on the 500 and I think eek it works on the 650:-

. Look at the pipes into the oil tank from the rear, notice that you can still see both pipes, apparently side-by-side?

. Also look at the junction block on the engine, the pipes are also side-by-side?

. If so, the corresponding steel pipes - 'left' and 'right' - should be connected together with the flexible pipes.

Originally Posted By: Michael
the bike does run but I'm hesitant to do so without knowing for sure the oil is pumping, does there need to be oil in the system

Doesn't need to be primed (unless the engine has a Morgo rotary pump) but, before you go any further, read this article. I appreciate it's aimed at triple owners, but note the advice about oiling the top end and pouring some oil into the crankcase; this'll be flung about by the crank as soon as the engine starts and lubricate things like the cams, which wouldn't otherwise be lubricated until oil drained back down into the sump ... several seconds after the engine started ... eek The return side of the pump will also start pumping as soon as you start the engine, rather than the aforementioned several seconds later.

Hth.

Regards,

#524805 - 01/26/14 4:14 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Originally Posted By: Michael
OK I've done all that to no avail, the bike does run but I'm hesitant to do so without knowing for sure the oil is pumping, does there need to be oil in the system ie primed? before it will pump??

Are you saying you can't get oil to pump out when you remove the plug on the timing cover?If so,you have a problem.

#524810 - 01/26/14 5:05 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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A hah, just got oil pumping through! now just to get the mixture right, and time it properly. thanks heaps for all the help fellas!


Bucko
1966/68 T120 Bonnie
#524811 - 01/26/14 5:09 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Michael Offline
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Australia
Seems that I did have the pipes on opposite what they are supposed to be (idiot), now have oil returning back through the tank and to the top end YAY!


Bucko
1966/68 T120 Bonnie
#524825 - 01/26/14 8:25 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Back on the mainland!
Not to pile on, but if you mixed the feed and return oil lines, are you sure you oriented the oil pump gasket correctly?

Steve


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

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
#524827 - 01/26/14 9:04 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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Dick Harris Online content
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Steve, don't scare the poor guy any more!!! He has oil returning so the gasket must be OK. Dick

#524840 - 01/26/14 9:49 am Re: T 120 bonnie air coming out of carby [Re: Michael]  
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JubeePrince Offline
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Ha! Sorry Dick....my mom always told me I worry too much! beerchug

Steve


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

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
#524867 - 01/26/14 12:06 pm Re: T 120 bonnie air coming out of carby [Re: Michael]  
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John Healy Online content
John Healy  Online Content



Joined: Mar 2005
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Boston, Massachusetts
Quote:
Doesn't need to be primed (unless the engine has a Morgo rotary pump) but, before you go any further, read this article. I appreciate it's aimed at triple owners, but note the advice about oiling the top end and pouring some oil into the crankcase; this'll be flung about by the crank as soon as the engine starts and lubricate things like the cams, which wouldn't otherwise be lubricated until oil drained back down into the sump ... several seconds after the engine started


The word Primed is often misused when referring to bringing a piston oil pump engine to life. Yes, gear pumps MUST be "primed" in the sense that they, and the oil lines feeding them, should be full of oil before any attempt is made to start the engine. Failing to do this almost insures some premature plain bearing damage.

But that doesn't mean filling the feed oil line prior to starting with oil on a piston pump engine, should be ignored. The first thing you must do with a piston pump is verify that it will pump BEFORE you mount it to the engine.

After insuring that the pump is clean of any swarf, pull up the plungers out of the pump until they clear the upper transfer holes. Fill the upper transfer holes with oil. One at a time depress the plungers. At first you should feel resistance as the oil pushes against the ball/spring. When the pressure exceeds the spring pressure, oil should squirt out of the lower transfer hole 6 or 8 feet across the room. With the same piston place your finger over the upper transfer hole and draw the piston out of the pump. The ball should hold vacuum and the piston should snap back into the pump. If the pump passes these tests it is set to install.

The next thing you should do is fill the crankshaft with oil. Before you install the timing cover take a squirt can, Place the end of the tube into the hole in the crank and fill the crankshaft with engine oil. If the timing cover is already on you can remove the plug/oil pressure gage on the front of the cover. It is not as easy as squirting oil into the end of the crankshaft, but does the same thing.

Words to the wise about replacement oil pumps. When proven, the aftermarket pumps work every bit as good as the original. But you must be diligent as there are a couple of things you must be made aware of. One brand of pump comes with the two bottom plugs left loose which is to allow you to make sure the pump is free of swarf.

Now I am going to get a bit of heat for bringing this up, but here goes:
Here's what to look for on these after market pumps: When you check the pump that comes with the bottom plugs loose, as long as you don't tighten the plugs, the pump always tests good. When you tighten the plugs one, or both, sides of the pump fails the test.

ALWAYS test the pump after the bottom plugs are tightened.

What is happening is the top part of the plug is not centered on the ball and as you offer the plug it moves the ball off of the seat. (The pumps in question here have a message on them to check for swarf and tighten the plugs.) This will not allow the pump to work. Return the pump to whoever you purchased it from!

Another brand of pump had a batch where the pistons themselves were too long. At the bottom of the stroke they hit the bottom of the pump. To say the least this is not a good thing is an understatement. So when installing a new-to-you pump verify that the pistons have clearance at the bottom of the bore at full depression. To do this place the oil pump drive pin on the cam nut as close to bottom dead center as you can. Place the drive block on the pin and offer the pump to the studs with the pistons fully depressed into the pump. You should have to lift the pistons out of the pump for the slots to engage the drive block. If do not have to lift the pistons or the piston slots will not go over the drive block return the pump.

This first problem seems to be a random one while the second seems to be limited to a single batch of pumps. Once this is sorted both of these aftermarket pumps work as good as the original.

About Phil Pick's article on bringing a triple to life there is one thing he fails to address. I think it is the most over looked part of the triple's oiling system. The oil filter cavity is fed by the oil pump and then feeds oil directly to the mains and eventually the rod bearings. It is a pretty big cavity and when it is empty, such as when the motor is first started or a new oil filter has been offered, it takes the oil pump a few seconds to fill the cavity. In the meantime the mains, and especially the rods are running without oil flow.

You would have to been "living under a rock" not to have heard that start-up from cold is the most stressful time for the engine's main and rod bearings. Now imagine doing this without any oil flow for the time it takes to fill the oil filter cavity. Add to the problem people who start their triple without priming the pump, and oil lines before they attempt t start the engine. The rods and mains could be running without oil flow for minutes.

If you are preparing your triple for starting, or have just changed the oil filter, make sure the oil filter cavity is full of oil.



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