It lives

[Tomcat]

Originally Posted by ink ink

Could it be vibration-induced fuel frothing?

I'll bear that in mind if I can't find anything wrong oil-wise, especially as the spectators said it wasn't smoking. I'd expect to see it on both if that was the case though

[ink ink]

Originally Posted by Tomcat

I'd expect to see it on both if that was the case though

Yes, but you never know with these evil things.

The other thing I had was vibration unseating the float needles so letting too much fuel in. You could sit parked and rev it up to 4000 and fuel would come out of the ticklers.


But if the plug is oily I suppose oil must be involved.

[Tomcat]

Well, here's why it went onto one.



One of the super-duper light carbon fibre pushrods collapsed. TBH I'm not surprised as CF is very strong in tension but not in compression. Still, they'd apparently been running fine before so who knows I've got a set of standard ones so those will go in - doesn't seem to be a huge weight difference by feel.

Next stop Basset Down to get the crank rebalanced. The consensus seems to be 80% balance factor in a rigidly mounted engine. God knows what it is now but one thing's for sure, I'm getting rid of the Carrillo rods. Strong they may be but by eck they're heavy with it.

Rod........Small end.........Big end.......Total weight grammes
Standard....115................260............. 375
Carrillo.......190................310............. 500

Pistons and bores look OK, pretty much run in which isn't bad for about 20 miles running! I reckon the oiliness must have been from doing half a lap only firing on one.

Gearing is now sorted, for some reason I had the lowest geared combination of sprockets fitted Back to trial and error but what's on now should be better. I'll sort it out next week when I go back to Mallory after the rebuild.

Last problem is the oil leak and that seems to be coming from the head joint. Odd because the head shows no signs of blowing and there's only the pushrod tunnels containing oil in the area, and I sealed them with 3bond. More trial and error I guess

[ink ink]

People who know about race tuning classics (I don't) tell me rigidity in the pushrods is more important than weight, within reason.

[Tomcat]

Originally Posted by ink ink

People who know about race tuning classics (I don't) tell me rigidity in the pushrods is more important than weight, within reason.

It's a trade-off between avoiding valve float (lightness) and following the cam profile (rigidity). When you have a mechanism that's subject to some fairly hefty reciprocating stresses you want both, really - strength for reliability and lightness to reduce stress levels. It's a no-win situation

[protoborg]

Now we're into a new year are there any signs of life or is it in theatre with its guts spread around?

[ink ink]

I'm considering increasing balance factor on my Triton by arbitrarily drilling the flywheel near the big ends, reaching it through the sump plate.

Instinct and components leaping around tell me there's too much up and down and not enough back and fore in the vibration.

Do you dare me to do it?!

[Olly]

Originally Posted by protoborg

Now we're into a new year are there any signs of life or is it in theatre with its guts spread around?

It goes really rather well:

[protoborg]

Originally Posted by Olly

It goes really rather well:

IIRC it got major belly ache at Saltzburg, is that right?

[Tomcat]

Originally Posted by protoborg

IIRC it got major belly ache at Saltzburg, is that right?

One of the wires in the plug to the Interspan ignition unit snapped, easily repaired back home and the bike was out again at Cadwell for the season closer this year.

The shortstroke engine is now looking closer to reality as I have finally got the Nourish crank (only 8 months wait!) so I can start building that up. Expect more detail as it goes

[ink ink]

Originally Posted by ink ink

I'm considering increasing balance factor on my Triton by arbitrarily drilling the flywheel near the big ends, reaching it through the sump plate.

Instinct and components leaping around tell me there's too much up and down and not enough back and fore in the vibration.

Do you dare me to do it?!

I must have dared myself. Drilled it today. Will try a jaunt on the road tomorrow.

[Rode Drage]

Superb preparation TomCat I started racing with a Commando Production Racer and then got a Seeley Commando like yours. Polished Alloy tank and British Racing green seat unit and fairing. Ha, I sat looking at it for hours in the garage, waiting for the next race. I wish I'd known how much they were going to be worth ... in 2010. I'd have mothballed it along with the ES2 and Domi 99 I bought for a Fiver each as a 15 yr old

[ink ink]

Originally Posted by ink ink

I must have dared myself. Drilled it today. Will try a jaunt on the road tomorrow.

Definitely much smoother at 5000 rpm. 6000 is still pretty buzzy, but that hardly matters so much. I'll make no more changes for a while.