Classic Triumph Bonneville

[JackyJoll]

......... Then there's no bloody excuse for the clutch being shit.

It doesn’t need an excuse.

[Mr. Dazzle]

I relapped the hub onto the output shaft today. I've got no pictures though, so as far as the Internet is concerned it didn't happen! However, I'll tell you what I did anyway.

After searching the Triumph forums, where 10 people will give 11 answers to every Q, I did the sensible thing and searched machinists forums instead. I specified lapping loads of times but I've never actually done it.

Bit o' fine grinding paste - there were no obvious burrs/nicks - then slide the hub on and rotate back and forth about 20 degrees. Do that maybe a dozen times, then rotate the whole thing 90' and repeat. Keep doing that until both tapered surfaces are a uniform matte grey. Which they now are. Clean with paraffin very very thoroughly.

Must have done an OK job, if I put the bike in gear I can now slide the hub on and turn the gearbox shaft to make the wheel go around, only very light pressure required to push the hub on the shaft so it grips.

I've also cleaned all the old gunk and gaskets off the casing while I wait for my bits to arrive.

[JackyJoll]

Sounds like successful grinding-in.

[Mr. Dazzle]

7 Triumph clutch plates, ah ah ah....

[Mr. Dazzle]

I started reassembly of the clutch today.

The basket is original, as are the small shaft/hub and the twenty little rollers. Those rollers are loose, I held them in place with a dab of grease. The bit with the three bolts holes is new (that bit has cush rubbers in) as is the big washer.



The basket runs on those twenty rollers and the big washer is a thurst washer...basically one designed the take axial loads. It's sandwiched between the shaft and the basket, underneath the basket in this shot. That hole with the keyway is one half of the taper I've reground.



After that I just checked all my new plates fit. Which they appear to do. Weirdly they fit better in some rotational positions than others and - less weirdly - they're much less rattly in the grooves that the old ones.

[JackyJoll]

Are you considering balancing it?

[Mr. Dazzle]

No, because:

a) The rest of the bike wobbles so much it seems kinda pointless
b) The basket wobbles so much on the hub it seems kinda pointless
c) Perhaps most importantly of all, I didn't know that was a thing people did.

[JackyJoll]

The basket doesn’t wobble when your hand is off the handlebar clutch lever.

[Mr. Dazzle]

I put the primary drive back on tonight. Here it is looking pretty much like it did before I took it off, only cleaner....



Doing the centre bolts up is a bit of a challenge on this bike. Normally you'd put it in gear then use the back brake to hold the wheel still. This bike has rearsets, so the clutch nut is right behind the brake lever (hence why the left footpeg is missing in these pics). I ended up putting in gear then doing the bolt up while sat on it with the wheel wedged against the wall. S'now completely wobble free.

Old (right) and new clutch springs. The old ones are shorter and almost certainly stiffer. I'd guess they're either upgraded or T140 ones. I'll keep hold of them just in case I need to use them, the new ones are standard T120.



I've put everything back on now but not fully tightened and trued up the pressure plate. Even so, in its current nominal state the kicker now makes the engine turn over every time . Just as importantly, pulling the clutch does what it's supposed to aswell!

[weeksy]

Nice work boy! Excellent stuff

[JackyJoll]

Could be an October 1970 engine number.

https://www.fagengine.com/blogs/tech/tr ... 2033615%20

[Mr. Dazzle]

October 69 (week N) but 1970 model year (that's the D). Went through that one with the nerds on the other forums ND can also mean Oct 70 yes, but ND3 something is a 70 model built in late 69, ND6 something is 70/70 apparently.

Frame and engine match.

[Nidge]

I suspect the old springs have compressed beyond their service limit and you might end up getting new uprated/T140 replacements. Certainly the 650 springs I have in my stock T140 are marginal (despite the 7 plate conversion), very occasionally I get a bit of slip as it comes onto cam at about 4,000 rpm. If all the performance mods yours has make more power than a 750 (which I suspect they do) then the clutch will be the weak point (a fairly familiar old Triumph story....)

[Mr. Dazzle]

I suspect the old springs have compressed beyond their service limit and you might end up getting new uprated/T140 replacements. Certainly the 650 springs I have in my stock T140 are marginal (despite the 7 plate conversion), very occasionally I get a bit of slip as it comes onto cam at about 4,000 rpm. If all the performance mods yours has make more power than a 750 (which I suspect they do) then the clutch will be the weak point (a fairly familiar old Triumph story....)

I'd be curious to know how much power this bike actually has....not curious enough to put it on a dyno though.

It's a 650 obviously. Its got "hot" camshafts, I did try to find out what but I couldn't see many details with my mirror. I think its the classic hot cam everyone has. Then also got the 11:1s, nearly straight through exhausts (they do have a small baffle plate in them) and the filter free inlets.

Technically it's slightly more than 650 actually cause its got a plus 40 overbore

High 40s or low 50s would be my guess?

[Mr. Dazzle]

I made a stab at adjusting the clutch plate so its true....not sure i did it right, but its straighter than it was.

I also went to adjust the primary chain tension, but I don't have the tool. I thought it did. So I've got a 6 quid tool on its way to me. Bit of an arse, you have to drain the primary case oil to adjust said tension and it makes far more sense to do it when it is open like this.

Now the clutch is "tight" I had a practice kick on it. Really not sure I'll be able to get it going it's got some properly meaty "dooofs" in the piston when you kick it now. At the top of the compression it'll easily hold my weight on the kicker.

My FiL rode it 30 years with 11:1s so it can't be that bad! Just need the knack...like with most things on this bike it seems.

[David]

My BSA is that way....and it only has one "doof" so is a swine to get going. Sometmes, however, it just sort of starts.....

[Mr. Dazzle]

TBf it nearly caught even with the duff clutch.

I've heard that if a Triumph doesn't start by the second kick there's something wrong with it. We shall see how true that is

Apparently my FiL would sometimes just give up and accept the fact she doesn't want to start today.

[David]

It's karmah...or the Prince of Darkness.....

[David]

What you don't want is it kicking you back.

[JackyJoll]

What you don't want is it kicking you back.

Not a big problem on a Triumph twin.