73 Tiger 750 TR7RV - Much Improved

[ManInTheJar]

I bought my Tiger 750 last September. It was a fairly tidy bike on the surface and had been restored approximately10 years ago when a belt drive, spin-on filter and Amal Premier were fitted. It had several oil leaks, wasn't the greatest of starters and needed a bit of fettling to bring it back to what it should be. Since getting it I have given it a good going over and major service. I also

• Re-wired using new wire, sleeving and good quality connectors I am currently running an LED pilot and Halogen BPF main bulb in the headlamp pending an upgrade to a H4 style headlamp
• Fixed a major leak on the output shaft whilst also repairing the butchered sprocket access hole and replaced the 21 tooth sprocket with a new standard 20 tooth one.
• Upgraded the clutch with new rubbers, 7 plate kit with 650 springs and new splined section of the clutch hub.
• Fitted a 3 phase alternator and regulator/rectifier
• Rebuilt the twin disk front brake with new seals (callipers and master cylinder) , nipples, lower pipes and crossover pipe incorporating a hydraulic brake switch. The callipers and master cylinder bracket were painted using calliper paint whilst they were stripped.
• Fixed an issue with the studs on the sump plate and re-instated a top hat strainer to supplement the spin on filter.
• Rebuilt the Anal premier and fixed the non-operational choke caused by the wrong carb top.
• Fitted a Tri-Spark ignition system with dual output coils.
• Re piped the crankcase breather, front to rear.
• Painted lots of ancillary bits such as the battery box, brackets, footrests, coil tray etc
• Replaced loads of chewed and rusty fasteners
• Lots of other bits and pieces which I've forgotten

On stripping the chaincase I found it was running dry, presumably because it had a belt drive (and also a non-sealing sprocket cover). However there was no oil seal on the crankshaft and the three level holes were clear. As it seemed to run OK like that I have left this arrangement, essentially giving it the original breathing arrangement without priming the chaincase thus running the clutch and belt dry - except for any oil vapour which enters the crankcase.

The bike runs like a dream now, starts first or second kick both hot and cold, runs, brakes and handles well and is totally transformed. There are still a couple of minor oil leaks and some other bits and bobs to fettle but nothing to worry about.

Here are a couple of photos of it in action yesterday.

 

[solomon]

On stripping the chaincase I found it was running dry, presumably because it had a belt drive (and also a non-sealing sprocket cover). However there was no oil seal on the crankshaft and the three level holes were clear. As it seemed to run OK like that I have left this arrangement, essentially giving it the original breathing arrangement without priming the chaincase thus running the clutch and belt dry - except for any oil vapour which enters the crankcase

I always understood the three holes allowed oil to pass into primary side. Indeed, sometimes I don't put oil in there after draining, it fills back quickly.

 

[grandpaul]

Dang, that's a beauty! Very clean, and should serve you quite well.

It's always best when one is able to do service and maintenance for themselves, and DO IT CORRECTLY.

 

[solomon]

It's always best when one is able to do service and maintenance for themselves, and DO IT CORRECTLY

Not sure if that refers to me not filling primary? Point I was making, something is odd, if holes aren't blocked and no oil passes?

 

[sikatri]

Nice job!

 

[CarlS]

I bought my Tiger 750 last September. It was a fairly tidy bike on the surface and had been restored approximately10 years ago when a belt drive, spin-on filter and Amal Premier were fitted. It had several oil leaks, wasn't the greatest of starters and needed a bit of fettling to bring it back to what it should be. Since getting it I have given it a good going over and major service. I also

• Re-wired using new wire, sleeving and good quality connectors I am currently running an LED pilot and Halogen BPF main bulb in the headlamp pending an upgrade to a H4 style headlamp
• Fixed a major leak on the output shaft whilst also repairing the butchered sprocket access hole and replaced the 21 tooth sprocket with a new standard 20 tooth one.
• Upgraded the clutch with new rubbers, 7 plate kit with 650 springs and new splined section of the clutch hub.
• Fitted a 3 phase alternator and regulator/rectifier
• Rebuilt the twin disk front brake with new seals (callipers and master cylinder) , nipples, lower pipes and crossover pipe incorporating a hydraulic brake switch. The callipers and master cylinder bracket were painted using calliper paint whilst they were stripped.
• Fixed an issue with the studs on the sump plate and re-instated a top hat strainer to supplement the spin on filter.
• Rebuilt the Anal premier and fixed the non-operational choke caused by the wrong carb top.
• Fitted a Tri-Spark ignition system with dual output coils.
• Re piped the crankcase breather, front to rear.
• Painted lots of ancillary bits such as the battery box, brackets, footrests, coil tray etc
• Replaced loads of chewed and rusty fasteners
• Lots of other bits and pieces which I've forgotten

On stripping the chaincase I found it was running dry, presumably because it had a belt drive (and also a non-sealing sprocket cover). However there was no oil seal on the crankshaft and the three level holes were clear. As it seemed to run OK like that I have left this arrangement, essentially giving it the original breathing arrangement without priming the chaincase thus running the clutch and belt dry - except for any oil vapour which enters the crankcase.

The bike runs like a dream now, starts first or second kick both hot and cold, runs, brakes and handles well and is totally transformed. There are still a couple of minor oil leaks and some other bits and bobs to fettle but nothing to worry about.

Here are a couple of photos of it in action yesterday.

Beautiful bike. Very nice work.

 

[Rudie]

understood the three holes allowed oil to pass into primary side. Indeed, sometimes I don't put oil in there after draining, it fills back quickly.

Three holes located correctly, if the oil level in the crankcase ever reaches that high, the engine has a problem ...

Triumph intended pressure in the crankcase caused by the pistons descending to be vented into the primary through the drive side main bearing; however, some pressure will obviously pass through the three holes. The vented gas contains oil droplets, that Triumph intended would stay in the primary because the volume of the primary was expected to slow down the speed of the vented gas before it vented to atmosphere. The three holes' primary purpose was to prevent the primary oil level ever reaching the spinning alternator rotor because, if it did, the engine's power would be sapped noticeably.

 

[solomon]

Oil level is generally self-finding in the primary. In this case the bearing must have a seal added. It's still odd though no oil, even small amount, gets through the three holes when the engine breathes, and there must be some splashing around. And if the bearing has a seal, how is the engine adequately venting?
OP states there is no seal on the bearing. Something is odd.

 

[ManInTheJar]

Oil level is generally self-finding in the primary. In this case the bearing must have a seal added. It's still odd though no oil, even small amount, gets through the three holes when the engine breathes, and there must be some splashing around. And if the bearing has a seal, how is the engine adequately venting?
OP states there is no seal on the bearing. Something is odd.

I found it strange too.

When I opened the chaicase there was barely a teaspoon of oil in the bottom of it and a thin film of oil coating everything.

I expected to find the three holes blocked and a seal on the crank. Removing the rotor revealed no crank seal and I used a bit of copper wire to confirm the three holes were clear (they were still clear and sharp with no signs of any attempt to seal them).

The only other factors were a butchered sprocket access hole (presumably to fit the 21 tooth sprocket) and no oil seal in the sprocket access cover. The hatch edges had been heavily sealed with silicon to compensate for the butchered hole but the missing seal meant it was venting to atmosphere around the mainshaft. I have now fixed all this and that area is sealed now.

The belt is of the polypropylene type and in good condition and doesn't seem to have been affected in any way with the film of oil covering it. On that basis I decided that if it ain't broke don't fix it and I have left the crank and three holes as found and not primed the crankcase. I will monitor it to check if oil accumulates (hasn't yet) but fully expect a film of oil to cover everything.

One other relevant point is that a decent but not excessive quantity of oil ran out of the crankcase when I removed the filter plug for cleaning. So it's not a case that the crankcase running dry was stopping oil reaching the chaincase.

 

[Rudie]

Oil level is generally self-finding in the primary. In this case the bearing must have a seal added.

Politely, this does not read correctly.

When Triumph changed the twins' crankcase venting - first engines late in the 69 model year, first drawn and listed in the 70 parts books - specifically the drive side main bearing oil seal was not fitted so that the crankcase could vent into the primary case. The main bearing seal was still drawn and listed in some versions of the 70 twins parts books but that is a misprint, the seal was never fitted.

The drive side main bearing oil seal was only fitted to earlier twin engines in conjunction with the hollow inlet camshaft driving the timed breather in the drive side crankcase, that vented by the gearbox final drive sprocket.

Primary oil level is self regulating only in engines venting through the drive side main bearing. Earlier engines, primary oil level must be set using the level hole towards the front of the primary chaincase.

 

[Rudie]

stripping the chaincase I found it was running dry
As it seemed to run OK like that I have left this arrangement

Original chain primary, there was intentionally a small quantity of oil in the primary, the bottom run of the chain ran through it, splashed the oil around the primary, some ended upon the clutch rollers to lubricate their rolling surfaces. If your bike's belt is oil resistant ...?

 

[ManInTheJar]

Original chain primary, there was intentionally a small quantity of oil in the primary, the bottom run of the chain ran through it, splashed the oil around the primary, some ended upon the clutch rollers to lubricate their rolling surfaces. If your bike's belt is oil resistant ...?

I suppose it is a matter of weighing the pros and cons. One con is having to periodically grease the clutch rollers but I have packed them with quality grease and as they only turn when the clutch is operated I shouldn't need to re-pack them that often. I also wonder how much oil finds it way to the rollers on a non- modified primary.

 

[grandpaul]

Not sure if that refers to me not filling primary? Point I was making, something is odd, if holes aren't blocked and no oil passes?

Not at all. You DO seem to know what you're doing, just have a bit of a baffling issue...

 

[randykyra]

wow, great looking bike. Mine is still in pieces but maybe someday...

 

[Lordmac]

I bought my Tiger 750 last September. It was a fairly tidy bike on the surface and had been restored approximately10 years ago when a belt drive, spin-on filter and Amal Premier were fitted. It had several oil leaks, wasn't the greatest of starters and needed a bit of fettling to bring it back to what it should be. Since getting it I have given it a good going over and major service. I also

• Re-wired using new wire, sleeving and good quality connectors I am currently running an LED pilot and Halogen BPF main bulb in the headlamp pending an upgrade to a H4 style headlamp
• Fixed a major leak on the output shaft whilst also repairing the butchered sprocket access hole and replaced the 21 tooth sprocket with a new standard 20 tooth one.
• Upgraded the clutch with new rubbers, 7 plate kit with 650 springs and new splined section of the clutch hub.
• Fitted a 3 phase alternator and regulator/rectifier
• Rebuilt the twin disk front brake with new seals (callipers and master cylinder) , nipples, lower pipes and crossover pipe incorporating a hydraulic brake switch. The callipers and master cylinder bracket were painted using calliper paint whilst they were stripped.
• Fixed an issue with the studs on the sump plate and re-instated a top hat strainer to supplement the spin on filter.
• Rebuilt the Anal premier and fixed the non-operational choke caused by the wrong carb top.
• Fitted a Tri-Spark ignition system with dual output coils.
• Re piped the crankcase breather, front to rear.
• Painted lots of ancillary bits such as the battery box, brackets, footrests, coil tray etc
• Replaced loads of chewed and rusty fasteners
• Lots of other bits and pieces which I've forgotten

On stripping the chaincase I found it was running dry, presumably because it had a belt drive (and also a non-sealing sprocket cover). However there was no oil seal on the crankshaft and the three level holes were clear. As it seemed to run OK like that I have left this arrangement, essentially giving it the original breathing arrangement without priming the chaincase thus running the clutch and belt dry - except for any oil vapour which enters the crankcase.

The bike runs like a dream now, starts first or second kick both hot and cold, runs, brakes and handles well and is totally transformed. There are still a couple of minor oil leaks and some other bits and bobs to fettle but nothing to worry about.

Here are a couple of photos of it in action yesterday.

It's always good to see another "old Triumph classic" back in action, especially when done right!

 

[Lordmac]

wow, great looking bike. Mine is still in pieces but maybe someday...

Not maybe . . . WILL BE

 

[Lordmac]

Politely, this does not read correctly.

When Triumph changed the twins' crankcase venting - first engines late in the 69 model year, first drawn and listed in the 70 parts books - specifically the drive side main bearing oil seal was not fitted so that the crankcase could vent into the primary case. The main bearing seal was still drawn and listed in some versions of the 70 twins parts books but that is a misprint, the seal was never fitted.

The drive side main bearing oil seal was only fitted to earlier twin engines in conjunction with the hollow inlet camshaft driving the timed breather in the drive side crankcase, that vented by the gearbox final drive sprocket.

Primary oil level is self regulating only in engines venting through the drive side main bearing. Earlier engines, primary oil level must be set using the level hole towards the front of the primary chaincase.

Rudy . . . thanks for CLEARLY explaining to everyone what in the heck is going on with that primary chaincase vent system and how it works.

 

[solomon]

Not maybe . . . WILL BE

Hmm. My 1977 T14O has been upstairs under the bed, in cupboards and in hallway for 'quite some time '.

Rudy . . . thanks for CLEARLY explaining to everyone what in the heck is going on with that primary chaincase vent system and how it works.

But the bike in question is clearly vents through bearing. Checked my primary oil yesterday because of this thread. It's about right, half inch deep, even though I didn't fill it. OP's bike remains a mystery why primary doesn't fill

 

[Lordmac]

Hmm. My 1977 T14O has been upstairs under the bed, in cupboards and in hallway for 'quite some time '.

But the bike in question is clearly vents through bearing. Checked my primary oil yesterday because of this thread. It's about right, half inch deep, even though I didn't fill it. OP's bike remains a mystery why primary doesn't fill

Some Triumphs don't follow protocol and are naughty.

 

[Lordmac]

Checked my primary oil yesterday because of this thread. It's about right, half inch deep, even though I didn't fill it. OP's bike remains a mystery why primary doesn't fill

Now you know where all that oil that leaks from your Bonnie goes . . .