Classic Triumph Bonneville

[Big Red]

I just tried swapping the plugs and the problem did indeed swap sides.

I had a spare plug in the garage, so I chucked that in and all seems well now. At idle at least!

It's the wrong grade of plug though, s'one "number" too cold. Enough to make the point though.

Result.

I have found that if you start cars/bikes every now and again and don't actually take them for a run, it must be the carbon build up not getting burnt of as they are never getting up to temperature, the plugs seem to die. No amount of cleaning can bring them back to life.
Very common and you can usually get them to perform as they should by making the spark jump, increasing the voltage. Soon as you plug the lead back in, they start to misfire again.

[Mr. Dazzle]

I've counted up how many bolts have escaped from the fairing. 5, out of 12

So today I shall be ordering a load of stainless Button head screws, locking nuts, washers, rubber wahsers and thread lock.

I took a brief vid yesterday to show my Dad the bike running. It's actually quite alarming how much the screen moves when you rev the engine.

[Mr. Dazzle]

I've just been out for a ~25 mile ride on the first part of my quest to sort the fueling. Before I left though I marked the twist grip to show where quarter, half etc. throttle are.



An important point is that its not the position of the grip which matters, its the position of the slides (the shiny cylindrical bit) in the carbs. I was surprised by how different half twist grip and half slide position are. The first 3/4 of grip movement only does half the carb movement.



Then I was off...ride around for about 5-10 miles so its properly warmed up, then tool along the A5 at exactly quarter throttle for about 7 miles. Then pull into a layby and whip the plugs out.



So at quarter throttle its not a million miles away and indeed the riding experience reflects that. That throttle position is about 75mph on the (shit) speedo. I was slowly catching and passing other cars, so I reckon that's about right. At that throttle position it will respond eagerly if you open up a bit more and there's no surging etc.

I turned around a came back, planning to do the same thing at half throttle. However anything above half throttle generated a slight vibration and a sound I can only describe as being like an arc of electricity. I need to work out what's going on there.

I did actually ride at full throttle just fine, taking the revs as high as I dare through the first 3 gears...seems fine then.

In general though I'm finding her more and more fun to ride. It's actually quite a friendly bike to ride, once you get used to the RHS gears and the feel of the throttle. The brakes aren't as bad as all that, I found they actually work better when a bit hotter. I had a scare when I smelled the classic burning pad smell, I thought something was going badly wrong with the engine before I clicked where it was coming from I reckon I must have burned some crap off or something, cause the initial bite has spontaneously improved loads.

I ground something out on a roundabout a couple of times. I thibk its the centre stand.

The pick up off idle and bottom end response to small throttle increments is great. Makes me want to try a modern air cooled big valve twin

[JackyJoll]

A Triumph 650 is a nice lively bike to ride.

[Mr. Dazzle]

In hindsight what I should have down was try riding along at half throttle in 3rd and in 4th to see if the sound/vibe changed.

Next time!

Also...man it throws a lot of oil about when you're riding! I think most of this is coming off the chain, im not sure. Can't see any major leaks, but the bottoms of the PRTs are a bit shit. Big surprise there.

It's nominally got a power lube system which drops engine oil on the chain. No idea if that's the culprit here, or if it even works.

[JackyJoll]

Everyone screwed the chain oiler shut.

[Mr. Dazzle]

Everyone screwed the chain oiler shut.

Clearly not everyone

[JackyJoll]

So far as I know, all schemes to lubricate the chain with engine oil were shit.

[A_morti]

Don't know if it's applicable but don't see why not:
Japanese bikes always have shouldered bolts through plastics. That way you can tighten them down properly without tightening against the plastic.
That might be the solution to losing fairing bolts, without having to tighten so much as to cause crazing.

[Mr. Dazzle]

Ha...now you're assuming its built properly

It's bolts through plastic with a nut on the other side. Nothing to bolt a should bolt tight too! S'not like a modern bike where you're bolting up to a lug/bracket/frame.

[JackyJoll]

Rubber or leather washers might help.

[weeksy]

Ha...now you're assuming its built properly

It's bolts through plastic with a nut on the other side. Nothing to bolt a should bolt tight too! S'not like a modern bike where you're bolting up to a lug/bracket/frame.

Install some dzus?

[Mr. Dazzle]

That would really be fully cafe wanker wouldn't it?

I plan on rubber washers, locking nuts and threadlock. Plus just keep an eye on them.

[JackyJoll]

Plus just keep an eye on them.

Look where you’re going!

[A_morti]

Ha...now you're assuming its built properly

It's bolts through plastic with a nut on the other side. Nothing to bolt a should bolt tight too! S'not like a modern bike where you're bolting up to a lug/bracket/frame.

Even so, you can put a big washer on the back and tighten against it. I am assuming the plastic is a consistent thickness. Plausible if plastic, less likely if it's GRP.

Probably the best option would be rubber wellnuts like on fairing screens. These would add tension without putting much pressure against the plastic.

[Le_Fromage_Grande]

I use wellnuts on fibre glass race fairings

[Mr. Dazzle]

Deffo something not right in the top half of the throttle range...I can get the sparkly electric sound on cue.

I've also lost the rocker inspection cap I replaced again. Gonna have to get them o rings and maybe some new spring retainer clips with a bit more spring.

I did hit a GPS verified 91mph though (indicated 110mph ), plenty more to give if I can actually get the top half of the throttle range to work properly. Managed a few clutchless shifts too, bollox to your QS says I!

I've done about 100 miles since the rebuild and got properly up to temperature a few times, so I've gotta retorque all the bolts, recheck the valve clearances and replace the oil now.

Really need to look into the ground clearance though, it's borderline dangerous on left handers. Exiting roundabouts on 70mph roads (never do much of that here!) is a bit fraught, doubly so 'cause there's no "give" in whatever is touching down.

[JackyJoll]

Has it got a centre stand with a long tang on it for your foot?

People used to saw that off.

[JackyJoll]

“Sparkly” sounds a bit like detonation (pinking). You have extra-high compression ratio pistons, haven’t you? They can cause pinking with road fuel.

One sign of pinking is specks like black pepper appearing on the plug insulator and the piston crown.

A slight rattle as you move from a standstill is something you can get away with. If detonation happens at speed, it will likely lead to overheating and seizure of the piston skirt to the bore. If it doesn’t seize, it will nibble the edge off the piston crown.

Can you avoid it my restricting throttle opening at lower revs?

Pinking can be mitigated by making sure the mixture is not weak. You can also retard the ignition a couple of degrees. Timing it any later than about 35 degrees will probably affect performance, which defeats the purpose of the racing pistons.

[Mr. Dazzle]

Its got 11:1 in yeah, plus hotter cams (still not 100% on what they are, even after we had a look at them). Timing was set to 38' when rebuilt, its got a solid state ignition so should advance/retard OK. Running on Shell V Power, 99RON and no ethanol...some of the cheaper super unleadeds achieve the high Octane via ethanol, but Shell and Esso don't. Even their E5 marked super is ethanol free.

At low throttle it seems fine.

My plan was just to go a size or two larger on the mains and see if that changes anything. If its running OK up to about half throttle any fuelling issue would be the taper of the needle or the main?

S'already got 230s in.