Classic Triumph Bonneville

[JackyJoll]

There are at least three different face radius specs on cam followers, but so long as both inlet followers look the same and both exhaust followers look the same, it’ll work.

[Mr. Dazzle]

Thing is, I reckon you'd be able to fit a nice lead in chamfer on the spindle without compromising it. Oh well.

Yep, you can! Or rather, the nice chap in the tool room at work can....



That should at least make it a tiny bit easier to build. Originally there was a sharp corner on there, which made it a pain in the arse to get the bits on even on the bench. The OE Triumph ones I took out (which don't have the spiral oil groove) had that chamfer on the end but my pattern ones didn't. Until now.

[cheb]

Haven't you got an angle grinder at home?

[Cousin Jack]

Haven't you got an angle grinder at home?

Or at least a Deremel.

[Mr. Dazzle]

No and no.

Why would I make a shit job of it at home when I can get a tool maker in a flat cap to do it properly?

[KungFooBob]

Depends, is the flat cap wearer called Fred?

[Mr. Dazzle]

The bigger issue is that I haven't done the HSE training/don't have appropriate headwear to use the bench grinders at work.

[JackyJoll]

Haven't you got an angle grinder at home?

Or at least a Deremel.

They still make files, you know.

[JackyJoll]

don't have appropriate headwear to use the bench grinders at work.

It’s all available on the Internet.

[Mr. Dazzle]

Tonight's job was refitting the tappet blocks. They're just interference fitted into the cylinders, you use a dedicated tool (basically a drift which looks like someone's o level metalwork homework) to drive them in.

I quadruple checked which is which though, the exhaust side has holes in it to allow oil flow to the exhaust tappets...which also have holes in.

I also tried just dry fitting the head to confirm I hadn't ballsed it up too badly.

[Nidge]

Looking good - I’m sure you have already done so but doubly check the block is square in the barrel. The locating bolt will still drew in even if the block is a couple of degrees off (which can result in premature wear to the camshaft or followers)

[Mr. Dazzle]

Well funny you should say that....


They do look a little on the piss. I was gonna ask the old boys on t'other forum. I just kept whacking the tool until it changed from "dink" to "donk". I'm always a bit wary on things like this...whack it too hard and you'll break something, don't whack it hard enough and it doesn't go all the way

[Nidge]

It's not so much that orientation (when it goes from dink to donk it's usually seated well), its more that it can rotate slightly in the hole as you drive it in. One method of checking is to put a length of square stock between the protruding ears and check it is square to the barrel on both sides if that makes sense- never try to rotate it once it's home, you have to drive it out and start again if you have any doubts

[Mr. Dazzle]

Oh right, see what you mean. I did that by eye, with a steel rule a reference aligning the holes, but it's not straightforward is it? I assume Triumph had an alignment tool in the factory or something.

I found you can 'steer' them a bit by putting torque on the drift tool while you whack it. I.e. twist it like a throttle grip as you go.

[Rockburner]

I was gonna ask the old boys on t'other forum.

Which one?

[Mr. Dazzle]

Triumph Rat.

I first joined there when I got my Speed Triple in 2003 but I forgot the log in details. There's some properly encyclopedic knowledge on there.

Just as well really, cause it often turns out the Triumph microfiches are wrong or there's some other reason to fit parts different to the official recommendation.

[JackyJoll]

Oh right, see what you mean. I did that by eye, with a steel rule a reference aligning the holes, but it's not straightforward is it? I assume Triumph had an alignment tool in the factory or something.

I found you can 'steer' them a bit by putting torque on the drift tool while you whack it. I.e. twist it like a throttle grip as you go.

Sounds like you know what you’re doing.

The followers can swivel a bit, to stay square to the cam.

[JackyJoll]

Triumph Rat.

Just as well really, cause it often turns out the Triumph microfiches are wrong or there's some other reason to fit parts different to the official recommendation.

They issued Service Bulletins with a recommendation to update the manual.

For instance, what recommendation did you follow for piston ring gaps?

[Mr. Dazzle]

Nidge got me paranoid about the alignment of the tappet blocks, I thought I got them in straight but I thought I'd better check using his method. Good thing I did.



Fortunately you don't have to take them all the way out to straighten, you can just knock them out a bit and then "tink tink tink" on the tool as you twist it so they rotate as they go back in...



After that it was time to start the job I actually set out to do: Check the crush on the push rod tube seals. The push rod tubes are just sandwiched between the head and the cylinder. The seals at either end are very slightly bigger than the gap they go in - like most o rings - so they get crushed when you clamp the head down tight. To check they're gonna crush the right amount you build everything up and then measure the daylight between the underside of the head (silver) and the top of the copper gasket. After messing around with a few seals I got to a gap of 30-35 thou, which is about right i think.

For instance, what recommendation did you follow for piston ring gaps?

I followed the recommendations of the people who did the cylinder honing I don't actually know what they did, but they give the impression they know what they're up to.

[Nidge]

That’s coming together nicely. Nice job on the tappet block alignment and spot on squish clearance!