Triumph T140 Bonneville rockerbox spindles are liable to leakage, particularly on excessive mileage bikes. Merely changing the tiny rockerbox O-rings usually is not sufficient. Many O-rings available on the market are sub-standard when it comes to high quality. Many are fairly merely the flawed dimension.
Sadly, you may must strive quite a lot of O-rings earlier than you discover a pair that work. However they’re low cost to purchase and simple to interchange. Fixing them simply appears extra difficult than it’s. This is how you can do it.
With the engine off and chilly, loosen and take away the aluminium inspection covers from the entrance and rear rockerboxes. Every cowl can be secured by six Allen screws. Loosen them only a fraction of a flip to take off the preliminary load. Now undo the Allen screws incrementally. That helps keep away from distortion. As soon as you have turned the Allen screws as soon as of twice, you possibly can chill out and take away them shortly.
There must be a paper gasket beneath every inspection cowl. Take away this gasket rigorously by scraping and peeling gently. Don’t use a tough scraper comparable to metal. Use a plastic or aluminium scraper of some type. Loosen the valve adjuster nuts on the rockers. This takes the load off the rocker spindles and the valve gear. Do NOT omit this step. You want solely make sure that the rockers are free. Do not take away the valve adjuster nuts.
If, nevertheless, you see that one of many valves is within the totally open place, gently rotate the engine (utilizing the kick starter) to shut the valve. This operation additionally helps take the load off the rocker gear and the rocker spindle. To facilitate closing a valve, you may want to take away the spark plugs to alleviate cylinder stress. The engine will flip over a lot simpler this manner.
However how will if a valve is open? Easy. Take a look at the ends of all of the valves the place they meet the rocker adjusters. If one of many valves is pushed all the way in which down by the rocker adjuster, it is open. You may wish to flip the engine over a number of instances to familiarise your self with the valve motion. It’s going to turn out to be clear if you take a look at it for some time.
Subsequent, you will want a particular software out there from good basic Triumph sellers. Low-cost to purchase (normally a number of kilos or {dollars}), this software is only a tapered tube about one inch (25mm) lengthy designed to suit snugly over the rocker spindle.
To make use of it, comply with these easy steps. First loosen and take away the precise hand dome headed nuts that safe the rockerbox oil feed pipes. There can be one for the entrance rockerbox, and one for the rear. The pipes are joined at a T junction which is in flip related to a rubber pipe. Take away the copper washer from beneath every dome nut. Take away the oil feed pipe. Take away the copper washers behind the rocker oil feed pipe. There must be one on every rocker spindle.
Now quickly substitute the dome headed nuts, however not the copper washers. Save the washers for later reassembly. The concept behind this stage is to get the rockerbox oil feeds out of the way in which. The dome headed nuts don’t should be fitted tightly. They’re changed solely to guard the threads on the top of the rocker field spindles. Wind them on simply a few turns.
Subsequent, utilizing a conceal mallet or rubber mallet, gently faucet one of many dome headed nuts. This can drive the rocker spindle throughout the rocker field from the precise aspect of the engine to the left aspect. Do not faucet the spindle various millimetres. The concept is to slip it throughout simply sufficient to reveal the O-ring and O-ring groove on the opposite finish of the spindle. Maintain tapping gently till you possibly can see the O-ring. Do that on the entrance and rear rocker bins. You may need to loosen the dome headed nuts a flip or two to facilitate this. It will likely be clear if you’re engaged on it.
Subsequent, take a small software with a degree or hook. Gently lever off the outdated O-ring from every spindle. They may now be flattened relatively than rounded. You may simply pull these off and throw them away. Wipe the top of the rocker spindle with a rag and examine that nothing is broken. If the spindle is broken, it should get replaced. If the spindle is in apparently good situation, oil it with some contemporary engine oil. Then oil one of many O-rings. Gently roll the O-ring over the top of the spindle and make sure that it is a comfortable slot in its groove. Do that with each rocker spindles.
Now you want that particular software talked about earlier. Oil it on the within with contemporary engine oil and slide it over the O-ring and rocker spindle. Take care to not snag the O-ring. Subsequent, take away the dome headed nut on the top of the spindle and quickly substitute the rocker oil feed. Change the dome headed nut and gently tighten while holding the particular software on the opposite finish of the spindle. The concept is to slowly draw the spindle and the O-ring by way of the small tapered tube. This helps cease the O-ring from snagging because it’s pulled again into the rocker field.
Do that with each O-rings. Verify as finest you possibly can that each O-rings are seated. If you happen to minimize or injury one, substitute and take a look at once more. Bear in mind to make use of loads of oil. The oil feed pipe is used right here purely as a spacer. You will see why shortly sufficient. Some homeowners attempt to faucet the spindle again by way of from the left aspect. It is best to keep away from this. Simply use the strategy above. It is slower, and extra managed.
Subsequent, anneal the copper washers. There must be 4; one to suit behind and one to slot in entrance of the rocker feed pipe on the precise hand aspect of the engine. To anneal, maintain every washer in a unadorned flame till it is cherry crimson, then drop instantly into chilly water. Copper may be safely annealed this manner. Ferrous metals should be cooled slowly.
Take away the rocker oil feed pipe and match a copper washer onto every spindle. Change the oil feed pipe. Put one other copper washer on every feed pipe. Rigorously substitute the dome headed nuts and tighten. This can pull the rocker spindle much more tightly into the rocker field. Do not over tighten.
Reset the valve clearances. Eight-thousandths of an inch for the inlet aspect, and 6 thousandths of an inch for the exhaust. It is uncommon to have the inlet rocker hole bigger than the exhaust, however that is appropriate for the T140 engine attributable to its camshaft profiles. Change the rocker field gaskets. A smear of gasket sealant will not damage. Do not overdo it. Tighten the rocker field inspection covers (incrementally, please).
Verify that every part is because it was. Begin the engine, make sure that the oil stress gentle goes out, examine for leaks, and trip the bike to heat completely. If, after a interval of some days or even weeks, the spindles aren’t leaking, they’re in all probability mounted. But when one or each nonetheless leak, you will must strive once more. It should work each time, however it would not. These are outdated bikes and wish a little bit fussing.
If in case you have persistent points right here, you possibly can strive eradicating each rocker bins and stripping utterly. Then you definately may strive machining a really small 45-degree bevel (or thereabouts) on the left aspect of every rocker field the place the spindle is drawn in. This bevel will help stop the O-rings from snagging on reassembly. Only a millimetre or two will suffice.
All the time purchase the most effective O-rings you possibly can from a good supply. Do not trouble attempting any type of resin or sealant across the O-rings. It hardly ever, if ever, works. Keep in mind that the spindles do not really spin. As an alternative, the rockers contained in the rockerboxes pivot across the spindle. The thing of the train is to feed these new O-rings gently into the rocker bins. Take a look at the issue in engineering phrases. By no means pressure something on this space. It should not want it. Simply be sluggish and methodical. If you wish to examine the spindle housing for put on, begin the engine and put a gloved finger towards every spindle in flip (left hand aspect, after which proper hand aspect).
If the spindles are bouncing up and down, or transferring in any respect, they want changing. Generally this motion is clearly seen. If you happen to want, you possibly can utterly take away every rockerbox and substitute the O-rings on the bench. However it is not obligatory for those who first take away the valve/rocker-load and use the particular software with loads of oil.
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