Classic Triumph Bonneville

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JackyJoll
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Re: Classic Triumph Bonneville

Post by JackyJoll »

Mr. Dazzle wrote: Tue Aug 17, 2021 8:47 pm Just been and checked to confirm what I've been saying is true.

With the primary case off and the plugs out I can turn the engine over with the crank nut OK. It turns over fine using one hand and a ratchet driver about 8" long. There's a strong hiss from the case breather ports as the pistons come down and you can feel the air coming from the plug holes. You can see the valves moving too.

With the plugs in its distinctly harder to turn over using the same method.
All good.
With the plugs out its hard to turn over using the kick. Even with plugs out I have to bounce on the lever to get it started, after that I can just about keep it going with leg power alone. With the plugs in its correspondingly harder, but still doable.
Mine isn’t hard to turn over with plugs out.

The first tooth on the kickstart quadrant sometimes jams but that doesn’t seem to be what you’re describing.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

Well if the engine turns over OK when you do it 'direct' and the kickstart is free moving when the clutch is pulled....

That only leaves one thing right? Transmission. Seems even more likely when you throw in the 'rear wheel doens't turn engine over easily' thing?
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Re: Classic Triumph Bonneville

Post by Count Steer »

Mr. Dazzle wrote: Wed Aug 18, 2021 7:52 am Well if the engine turns over OK when you do it 'direct' and the kickstart is free moving when the clutch is pulled....

That only leaves one thing right? Transmission. Seems even more likely when you throw in the 'rear wheel doens't turn engine over easily' thing?
The kickstart being free moving with the clutch pulled rather invalidates my last post about binding/jamming.
I'll have a reread of the thread......
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

BTW when I say it nearly catches, the best I've got is...

Kick - Doof - wet sounding slap - bang - bang - bang - fsssst........

If that makes sense :D

Second BTW - I also know that the kickstart doesn't directly use the transmission. The kicker should in theory drive 'straight through' the gearbox and out the other side using just one shaft. However if something in there is wrong/misaligned it'd suck loads of energy out of the kicks?
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Re: Classic Triumph Bonneville

Post by Count Steer »

Mr. Dazzle wrote: Wed Aug 18, 2021 8:08 am BTW when I say it nearly catches, the best I've got is...

Kick - Doof - wet sounding slap - bang - bang - bang - fsssst........

If that makes sense :D

Second BTW - I also know that the kickstart doesn't directly use the transmission. The kicker should in theory drive 'straight through' the gearbox and out the other side using just one shaft. However if something in there is wrong/misaligned it'd suck loads of energy out of the kicks?
That 'sound' makes perfect sense and brings back memories! (My shoulders slumped and head went down as I read it!) So, fuel and spark. Timing? (Irrelevant to the current issue probably).

The others on here are a lot more knowledgeable and up to date with the mechanicals than me so I'm just going through the same logic cycle as you but it does seem as if something is uggbered between the RHS and the LHS and, looking back, that picture of the rubbers looks a bit :shock: Haven't a clue how that could be related though.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

Rubbers were indeed FUBAR, it's got an all new centre now. Of course, something made them FUBAR to begin with and I assumed it was just age (52 years and 105,000 miles!) but maybe not.

It's deffo got fuel and sparks, I can see them for one and it makes plenty of explosions for two. Timing was the next job once it's actually running.
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Re: Classic Triumph Bonneville

Post by Count Steer »

Mr. Dazzle wrote: Wed Aug 18, 2021 8:29 am Rubbers were indeed FUBAR, it's got an all new centre now. Of course, something made them FUBAR to begin with and I assumed it was just age (52 years and 105,000 miles!) but maybe not.

It's deffo got fuel and sparks, I can see them for one and it makes plenty of explosions for two. Timing was the next job once it's actually running.
It's a shame you can't simply whip off the chain to decouple the crankshaft then see what it's like kicking through with the clutch engaged*. It seems every other combination has been tried!

*probably grasping at straws here :D
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

I think that if you put it in gear and kick it with the clutch pulled you'll make the wheel go around....I was contemplating if that would teach me anything.
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Re: Classic Triumph Bonneville

Post by Rockburner »

If the timing is out, it won't run.

I'm not up on Triumph twins, does it have advance/retard adjustment or is that automatic?
What's providing the spark: mag or alternator?
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

Alternator generates the juice, it's got a (retrofitted) solid state Boyer electric ignition and reg/rec.
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Re: Classic Triumph Bonneville

Post by Rockburner »

Mr. Dazzle wrote: Wed Aug 18, 2021 8:49 am Alternator generates the juice, it's got a (retrofitted) Boyer electric ignition.
But presumably still relies on contacts? Get the timing set right.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

It's got a crank position sensor where the breaker used to be, that sends a signal to the Boyer box which does the advance/retard. I can check the 0rpm timing but (obviously) not the advance/retard.
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Re: Classic Triumph Bonneville

Post by KungFooBob »

Have you left the ignition on for long periods without the engine running, iirc the Boyer boxes burn out if you do.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

Nope....

Got sparks when I should have sparks, so far as I can tell.
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Re: Classic Triumph Bonneville

Post by Count Steer »

Mr. Dazzle wrote: Wed Aug 18, 2021 8:41 am I think that if you put it in gear and kick it with the clutch pulled you'll make the wheel go around....I was contemplating if that would teach me anything.
It will be additional data! Whether it's useful depends on what happens when you do it :D

Have you changed anything since it was running that would affect the timing? (I think there are 2 separate issues here a) getting it turned over and b) keeping it running.
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

I've not deliberately done anything to the ignition since it was last running.

When it was running before it wouldn't rev out, but that was 'cause various connections had shaken loose. I've tightened everything down and it was running out to max revs (high as I dared at least, >6000) before it broke. It broke (not at 6000) when it dropped a valve guide - which I why I had to rebuild it in the first place.
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Re: Classic Triumph Bonneville

Post by Count Steer »

Mr. Dazzle wrote: Wed Aug 18, 2021 9:09 am I've not deliberately done anything to the ignition since it was last running.

When it was running before it wouldn't rev out, but that was 'cause various connections had shaken loose. I've tightened everything down and it was running out to max revs (high as I dared at least, >6000) before it broke. It broke (not at 6000) when it dropped a valve guide - which I why I had to rebuild it in the first place.
S'wot I thought.
Intrigued to know what happens with the in gear/clutch in test though. It will tell you something because you'll have another combination of factors.
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Re: Classic Triumph Bonneville

Post by Nidge »

I've just nipped out to the garage and tried it on one of the T140s. In gear clutch plates free and clutch pulled in the kick start does indeed turn the back wheel. Like you I'm not sure what this tells me....
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Re: Classic Triumph Bonneville

Post by Mr. Dazzle »

AIUI the kicker is on the right hand end of the (green) main shaft in this diagram. That taper on the left hand end is connected to the clutch (it's the same one I reground). Thus the kicker turns the main shaft.

When the bike is in neutral all of those gears are free spinning on the shafts, thus turning the main shaft just turns the clutch and then the engine (via the primary drive). So if you put it in gear and pull the clutch lever you'll turn the wheel but not the engine.

So in theory it is actually possible to kick start the bike when it's in gear on the centre stand, it'd just be bloody hard work 'cause you're trying to turn teh wheel too.

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Re: Classic Triumph Bonneville

Post by KungFooBob »

For £500 plus expenses I'll come set it on fire for you.