Triumphrat

dirtyharry · 06-23-2007

Finally have taken the bike for a shake-down ride and thanks to you people with your advice it runs great. One problem i still have is while riding it goes up through the gears ok but when i try downchanging it goes back to 4th ok but from there 3rd is possible sometimes and 2nd and 1st are virtually impossible. The gear lever won't push down any further when trying to get these lower gears. Is this a detent spring problem or what? Maybe someone out there has had the same problem. Also the clutch plates are still sticking and have to be freed up prior to riding. I don't know if this has anything to do with the gear problems but i intend to replace the clutch plates with Norman Hyde items.
Awaiting any thoughts, Dirty Harry. (1979 T140E)

daveforty · 06-23-2007

Clutch plates sticking and needing to be freed before starting is usual. I generally turn on the petrol taps and set the choke / cold start lever so that the engine is 'primed' when it is turned over while freeing the clutch. Thus it generally starts first kick.

Difficulties changing gear are most likely clutch related, if the clutch is dragging (not fully disengaging) then gear changes will be difficult. Try adjusting the clutch centre bolt and cable. If necessary it is fairly easy to dismantle / inspect / rebuild the clutch, a Haynes manual descibes the methods well enough, or people here will explain what to do.

There is a hairpin spring in the gear changing mechanism in the outer gearbox cover. If the spring breaks then the gearshift will only move in one direction, and once it is at the end it will stay there - permanently. The gear lever will move, but it will feel 'disconnected'. When it broke on my bike I could only shift downwards, resulting in a long (and slow) ride home in first gear.

Mecchanica · 06-23-2007

For big Triumph twins and triples, shifting problems are usually clutch problems, if all the parts are correct and have been assembled correctly.
First sort the clutch and then see what problems are left.
The clutch pressure plate must lift evenly and you need to have sufficient amount of lift.
First, run the adjuster at the handlebar and at the case back to provide the maximum amount of slack in the clutch cable. Remove the access plug in the middle of the primary cover. Loosen the locknut and using a small screwdriver fed through a 9/16 deep socket, which you can get a grip on, run the adjuster screw in until it bottoms, and do that a couple of times to get an idea of the point of contact. From bottom, back the screw off three quarter of a revolution (270 degrees). Then hold the screw with the screwdriver and spin the nut down to as tight as you can get it with your fingers. Then remove the screwdriver and tighten with a ratchet. Then back the case adjuster back to leave about an eighth of slack in the cable, and take that up with the handlebar adjuster. If this doesn't do it, you will have to go into it and change the plates and/or adjust the lift by turning the three spring retaining nuts. Make sure you also get new PLAIN plates or SANDBLAST your stock ones to get a good tooth. Use medium garnet or coarser. NOT glass bead. Careful application of a disc sander to get a crosshatch pattern on the plates will work, too. Use 100 grit silicon dioxide discs.
If you get the MAP clutch plate kit, you will be absolutely thrilled with the performance. You can use light spring pressure and get light lever feel without losing the good hookup. The plates....and the cables...will last a LONG time.
Run a good light synthetic non-energy conserving oil in your tank and engine...which is also the primary oil in the 70 and later twins. I like the Royal Purple 10w-30 in my 68 and synthetic ATF in the primary, which is separate. You can run much lighter synthetic oil, as the uniform molecular size provides excellent film strength and lubricity in lower viscosity oils and you get the advantages of the lighter oil circulating faster over wear points, reducing heating and wear.

[ This message was edited by: Mecchanica on 2007-06-23 14:47 ]

quagmire · 06-24-2007

What about the shifter cam plate? Could there be some funny notches that won't permit movement down in gear and only up in gear? Just thinking out loud.

Mecchanica · 06-25-2007

Yeah, I suppose that could be, but it would be rare, indeed. The five speed camplates are all hardened and ground. I have seen excessive wear on the 2-3 shift fork, but I don't think that would cause this. And the transfer quadrant is hardened, too. I have never seen one of these, four or five speed, which has shown ANY noticeable wear.
I would check the clutch out thoroughly first.

dirtyharry · 06-26-2007

I don't think the cam plate is the problem either as the bike has only done 12,000 miles. Mecchanica, i will look at the clutch adjustments in the next day or two and get back to you with results. Shift work is a curse!!!

dirtyharry · 07-03-2007

Mecchanica, i have adjusted the clutch as per your procedure and still no luck. Took it for a ride and as i said before, going up through the gears no problems. Down shifting however from 3rd down i have to keep lifting the gear-lever with the tip of my toe and then push back down to go down to the next gear. Clutch appears to be working fine once i free it up. Any ideas????.
Dirty Harry.

Mecchanica · 07-03-2007

I would change the springs in the shift mechanism....there are two centering springs, one of which is possibly broken, and there are two plunger springs. While there, you might want to change the kickstart return and kickstart ratchet springs, for good measure.
Pull the outer cover and remove the U shaped plate, held on with four nuts. The two suspect springs are under there. If you want part numbers, I can look them up. TXXX or something. Low numbers, as they have used the same ones forever.

dirtyharry · 07-05-2007

Have taken the gearbox outer cover off and what a bloody mess. The gearbox oil is emulsified and everything i can see has rust on it. Water has got in somehow by the look of things. Where it got in mystifies me. Anyway i'm going to order all new springs, seals and gaskets, and put new oil in and see how it goes.
Dirty Harry.

Mecchanica · 07-05-2007

Water can run down the clutch cable wire.....so look at the condition of THAT, too. It usually runs down the outer cable to the usually too-loose boot into the cover. There is a small breathing hole drilled in the cover which is unnecessary, but is also so tiny that it doesn't matter, but I plug them with a bit of sealer, just for the hell of it.
The heating and cooling of the engine causes the semi-sealed gearbox to breathe, inhaling moist air as it cools and then the moisture condenses. Regular long rides will cook most of the water out, but you are still better off using a synthetic gear lube...not motor oil or ATF, real 75/85 hypoid oil, like Mobil One or Royal Purple....the stinky stuff, as these gearboxes are not lapped or honed after hobbing, as are the wet sump modern bikes.
Mineral oil is reasonably hygroscopic and will absorb water, but the synthetic is almost immune to that. It also has stronger film and shear strength and heat resistance.

[ This message was edited by: Mecchanica on 2007-07-05 13:37 ]