Valves for Velocette MAC

[ellipsis]

I dropped a valve on my Velo and am in need of an exhaust and inlet valve for a MAC. Standard valves I believe.
Like an old wise fisherman once told me , fish your feet before before heading off in a boat. Maybe someone knows of something around here,before I start on the extensive net search?

[Grumph]

If you can piece together some specs from the wreckage: stem dia, head dia. rough overall length, I'll see what i can adapt.

Bring the damaged piston to the pre 82 cup meeting too please.

[ellipsis]

Will do. The tough old bird despite the valve bouncing around and smashing shit out of the piston and banging the head a bit is relatively cool. I have the stem and head in two bits.

http://i888.photobucket.com/albums/ac85/motorcycle-mania/velo%20piston%20and%20valve_zps4wewngks.jpg (http://s888.photobucket.com/user/motorcycle-mania/media/velo%20piston%20and%20valve_zps4wewngks.jpg.html)

[Grumph]

Will do. The tough old bird despite the valve bouncing around and smashing shit out of the piston and banging the head a bit is relatively cool. I have the stem and head in two bits.


This is where I'm supposed to say "call that damage ? Now this is damage" and post a pic which would embarass us both...so I won't.

[sidecar bob]

PM Swarfie, I think one of his did the same thing recently.
He will have the answers & probably the parts too. Fairly clever chap he is.

[nodrog]

I dropped a valve on my Velo and am in need of an exhaust and inlet valve for a MAC. Standard valves I believe.
Like an old wise fisherman once told me , fish your feet before before heading off in a boat. Maybe someone knows of something around here,before I start on the extensive net search?

http://www.outdoorspares.com/Genuine-Tecumseh-SPT40-Lawnmower-Engine-Inlet-Valve

[Grumph]

PM Swarfie, I think one of his did the same thing recently.
He will have the answers & probably the parts too. Fairly clever chap he is.

I'll endorse this though I think you may have spoken to him at Levels anyway. It gets you plumbed in to the NI velo clique who will have the right ideas on what to use. Do not ever use original parts in it....by the time they were making them their machinery was worn out. Modern parts are better made from better materials.

[J.A.W.]

This is where I'm supposed to say "call that damage ? Now this is damage" and post a pic which would embarass us both...so I won't.


Jeeze, can those ancient Pomgolian pussers even rev hard enough to do 'real damage'..

The only 'classic' 4T Honda I owned was a Yoshimura modified XL 250 ( ported head/hot cam/big bore slipper hi-comp piston/stiff valve springs/big Miki carb/trick 'supertrapp' pipe, & slotted into a CR chassis.. it was a bit of a precursor of the current 4T 250 MX..


It had a bad habit of breaking the stock cam-followers which weren't up to the high speeds/heavy duty forces involved, but I finally sold it when it punched a valve head through the Yoshi piston @ ~ 12-14K rpm.. & wrecked the head..

I kept that piston as an object d' art/object lesson to run 2Ts - for years, 'til I accepted an offer to buy it - from a Yoshi collector..



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[rudolph]

I have a 1949 BSA witch has a Chevrolet exhaust and a Ford inlet valve, I had the keeper slots moved down and the stem shortened by a guy at my old work, things for thees old bikes can be made for very cheep

I got the valves from the scrap bin at an engine reconditioner.

[ellipsis]

...all sussed now... thanks to Grumph, swarfie, Sidecar Bob, and me, deciding which way I would go...now I've gone...thanks...anyone have a 5TA (68.5 mm) piston to sell me?...so I don't have to leave my chair...

[rudolph]

...all sussed now... thanks to Grumph, swarfie, Sidecar Bob, and me, deciding which way I would go...now I've gone...thanks...anyone have a 5TA (68.5 mm) piston to sell me?...so I don't have to leave my chair...

have you tried classic cycles in upperhut?

[ellipsis]

have you tried classic cycles in upperhut?

I'm hoping to not have to go offshore, but I will if I have to...thanks...:niceone:

[Grumph]

...all sussed now... thanks to Grumph, swarfie, Sidecar Bob, and me, deciding which way I would go...now I've gone...thanks...anyone have a 5TA (68.5 mm) piston to sell me?...so I don't have to leave my chair...

tried Alan Bland yet ?

[ellipsis]

...got caught in a large set of viral road cones that hindered my progress towards his area, then got spat out and ended going somewhere completely elsewhere...it was 30+ so I squawked at other drivers and went to the Tai Tap for a beer...will try another approach road soon...6 weeks for CHS to do the valves, head, guides etc...that timeline suits my empty pocket...:motu:

[husaberg]

http://www.trademe.co.nz/Browse/Listing.aspx?id=1024223984

http://www.britishspares.com/Parts%20List/Triumph%20BSA%20Norton%20Parts/70-6907/040%20Piston%20Set%20%20%20Tri%205ta%2069mm%20040

http://www.southernspares.com/#!triumph-engine/c1dya

[ellipsis]

http://www.trademe.co.nz/Browse/Listing.aspx?id=1024223984

http://www.britishspares.com/Parts%20List/Triumph%20BSA%20Norton%20Parts/70-6907/040%20Piston%20Set%20%20%20Tri%205ta%2069mm%20040

http://www.southernspares.com/#!triumph-engine/c1dya

...and I've hardly been out of the chair...phew...who was it that said you were all useless cunts?, whoever it was, they need a good old spanking with a leather strop...for as long as they like...

[husaberg]

...and I've hardly been out of the chair...phew...who was it that said you were all useless cunts?, whoever it was, they need a good old spanking with a leather strop...for as long as they like...
Grumph likely has a GPZ750 piston or knows where one is to measure they do have a metric pin in 15mm though but i bet they are a better shape and better made.
It is what they used to use for the Honda CB350 racers.
Another option is C15 or B25 BSA or Rocket 3 trident
The C15 would likely best match the triumph head shape.

[swarfie]

...all sussed now... thanks to Grumph, swarfie, Sidecar Bob, and me, deciding which way I would go...now I've gone...thanks...anyone have a 5TA (68.5 mm) piston to sell me?...so I don't have to leave my chair...

Try Graeme Cole in the Tron. info@cycletorque.co.nz
He's on Turdme as Leo98 as well.

[Grumph]

When i had the damaged piston in hand, I reckoned it was a Hepolite which had been welded up to be run on alky. Way too big a crown.
Full, deep hemi chamber like the Aermacchis I'm used to. Like them a medium dome to get com up to 10.5 or so would work well.
I'm still searching my bits for the part set of 70mm Z1 wisecos I'm sure i have...

Edit - found them. Actually 70mm MTC forgings. Part set, one has damaged ring lands and they didn't make 3 cylinder Z1's...
17mm pin, 24.0mm deck height. Probably 10.25 in a Z1, given the bigger chamber but slightly longer stroke in the Velo, around 10:1 i'd think.
Cutaways are for 38mm inlet, 32mm ex. Plenty of meat if they need to go bigger.
Would need reringing but that's not a biggie.
Doubt you'll find anything much better Neil. Sure the owner will break the set anyway.
If any of the NI Velo crowd want one Nev, just ask.

[swarfie]

When i had the damaged piston in hand, I reckoned it was a Hepolite which had been welded up to be run on alky. Way too big a crown.
Full, deep hemi chamber like the Aermacchis I'm used to. Like them a medium dome to get com up to 10.5 or so would work well.
I'm still searching my bits for the part set of 70mm Z1 wisecos I'm sure i have...

Edit - found them. Actually 70mm MTC forgings. Part set, one has damaged ring lands and they didn't make 3 cylinder Z1's...
17mm pin, 24.0mm deck height. Probably 10.25 in a Z1, given the bigger chamber but slightly longer stroke in the Velo, around 10:1 i'd think.
Cutaways are for 38mm inlet, 32mm ex. Plenty of meat if they need to go bigger.
Would need reringing but that's not a biggie.
Doubt you'll find anything much better Neil. Sure the owner will break the set anyway.
If any of the NI Velo crowd want one Nev, just ask.

Sorry Greg it's too small for my KTT (74mm) and too big for a MAC or MOV. That'd be cheating and we wouldn't want that:innocent:

[Grumph]

Sorry Greg it's too small for my KTT (74mm) and too big for a MAC or MOV. That'd be cheating and we wouldn't want that:innocent:

Last time I looked which was yea, many years back, I thought the Reg allowed up to .080 over ?
Not a problem in the SI afaik

[swarfie]

Last time I looked which was yea, many years back, I thought the Reg allowed up to .080 over ?
Not a problem in the SI afaik

.060 is the Reg unfortunately, although I suspect there's a few "slightly" larger than that. I remember riding a quick short stroke BSA B31 before they changed the rules to only allow standard bore/stroke in the clubmans class (one I'd made a conrod for and running a TT500 crank) and another "competitor" pulling out 50 meters over me down about half the length of the back straight at Puke, on anther B31. The bike I was riding weighed heaps less than his and I was 20 kg lighter than him....go figure :confused:

[jellywrestler]

.060 is the Reg unfortunately, although I suspect there's a few "slightly" larger than that. I remember riding a quick short stroke BSA B31 before they changed the rules to only allow standard bore/stroke in the clubmans class (one I'd made a conrod for and running a TT500 crank) and another "competitor" pulling out 50 meters over me down about half the length of the back straight at Puke, on anther B31. The bike I was riding weighed heaps less than his and I was 20 kg lighter than him....go figure :confused:

and there's fuck all wind resistance on your swede.

[swarfie]

and there's fuck all wind resistance on your swede.

Jeez Thanx Spyda, I luv you too:msn-wink::eek::love:

[jellywrestler]

Jeez Thanx Spyda, I luv you too:msn-wink::eek::love:

at least you're easy to buy gifts for , just an extra large facecolth for all that extra face you have to wash...