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Ben
Honda CB350 Racers Promotion - Moderator
Victoria
288 Posts |
 Posted - 09 May 2008 : 4:15:06 PM
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Hi All,
Can anyone explain the logic behind limiting carb size in P3 to 38mm? Don't they use much larger sizes overseas?
Also, if Amal Mark 2 carbs are allowed (which and correct me if I am wrong are not technically period) why not big Mikunis? They are better value buying and more readily available.
Thoughts anyone?
However, if anyone has a 38mm Amal to sell me at mates rates I would no longer pursue this!
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 10 May 2008 : 12:44:33 PM
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I cannot give you a diffinative explanation at this stage.
BUT, beware of looking OS and wondering why the rules are different.
The UK has 3 sets of rules, NZ has a leaning to pommy bikes and the USA has different criteria as well.
I am not sure your 350 monster would be better with 38mm carbs, why are you leaning that way? |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
Edited by - john on 10 May 2008 1:35:53 PM |
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Allan
Site Moderator
National
599 Posts |
Posted - 10 May 2008 : 1:31:51 PM
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big carbs =long straighs PI/EC
small carbs=botton end "greater acceleration" short circuit MACP/WINTON SS |
Allan Greening |
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Ben
Honda CB350 Racers Promotion - Moderator
Victoria
288 Posts |
Posted - 10 May 2008 : 3:24:33 PM
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John, I am starting to build a new period 3 500 (single - ariel) solo and am collecting parts. Most things are proving no problem to find at decent prices, with the exception of a frame (wideline featherbed) and a carb (new amals in 38mm are not inexpensive and I think the 500 would take a 40-44mm carb nicely!).
Am happy to accept a frame/carb on loan from a kindly racer who would like to see another period 3 solo on the track!
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Allan
Site Moderator
National
599 Posts |
Posted - 10 May 2008 : 5:06:06 PM
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| and no use going bigger than the dia. of the inlet valve for cark size!! |
Allan Greening |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 10 May 2008 : 7:27:47 PM
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| How much are they? |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
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Ben
Honda CB350 Racers Promotion - Moderator
Victoria
288 Posts |
Posted - 11 May 2008 : 10:53:29 PM
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John,
Not sure if you are asking about the frame or carbs, so heres both....I can get a frame made for about $1500, a while off yet! The price of new carbs varies greatly, Amal Mark 2s (40mm) are anywhere from $300 to $400 and the equivalent Mikuni can be had for $130 - 200.
Cheers,
Ben.
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john feakes
Advanced Member
Victoria
791 Posts |
Posted - 15 May 2008 : 09:20:59 AM
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Ben, a featherbed for $1500 sounds good to me. A friend is currently looking at a Harley frame at U.S.$1650 plus shipping.
Amals are good, are authentic and parts are available. If you stay away from GP and TT versions you will not pay a fortune.
What size inlet valve do you propose running?
Cheers, John |
125 RIDERS' ALLIANCE
A wise person simplifies the complicated, a fool complicates the simple. |
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Ben
Honda CB350 Racers Promotion - Moderator
Victoria
288 Posts |
Posted - 15 May 2008 : 10:38:21 AM
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Hi John,
I agree, 1500 is OK, but I would rather try to find a rolling chassis with an alloy tank if possible. These go for 1500-3000 depending on condition. Would be much easier that way!
C'mon people - I have placed another wanted ad for the frame - I know at least one of you guys would have a frame/hubs sitting around in your quad garages full of parts, never to see the light of day again unless you dig it out to check that you still have it : )
Any leads appreciated!
RE: valve size, not sure yet, I think standard is about 44mm, so I will put in as big an intake as will fit (Manx has 2" [50mm] so will try to match it) and leave the exhaust standard (44mm as well I think).
What sizes are others running in BSAs, matchos, nortons, ESOs etc? |
Try Everything |
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john
Forum Moderator
Victoria
3130 Posts |
Posted - 15 May 2008 : 8:13:34 PM
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Ben, I lesson in life coming up.
1- Dont abuse people for collecting stuff, thats why it is not in the tip
2- Respect the choice of others to hold onto thier stuff for what ever reason they have. |
John Daley Sidecar #68
' there are those who do, those who dont do and those who undo. We must lampoon the latter." |
Edited by - john on 16 May 2008 10:56:22 PM |
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Ben
Honda CB350 Racers Promotion - Moderator
Victoria
288 Posts |
Posted - 16 May 2008 : 10:22:43 AM
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Abusing and disrespecting people? How presumptuous of you.
It is a light hearted remark on the nature of collecting, from one who also collects (albeit a few decades too late for all the good parts).
Please stay on topic.
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john feakes
Advanced Member
Victoria
791 Posts |
Posted - 17 May 2008 : 10:42:38 AM
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Hi Ben, I guess the sensible way would be to follow the lead of Manx or G50s but I'm sure they would be running GP or TT Amals that cost a fortune. There is a company in England that specialises in Amals and the prices have not struck me as being outrageous. I left my magazines at the South Morang kart track but will be there tomorrow and will check prices etc. for you. Can I suggest you place an ad in Just motor Bikes? I did when I was looking for a 125 and I was surprised that a very small wanted ad got a good response. As you say, try everything. Percy Verance will eventually win.
Cheers, John |
125 RIDERS' ALLIANCE
A wise person simplifies the complicated, a fool complicates the simple. |
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john feakes
Advanced Member
Victoria
791 Posts |
Posted - 20 May 2008 : 08:53:52 AM
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Well Ben, I opened my big mouth without checking the facts first. Sorry. The best I could manage for a new 38mm Mk2 with velocity stack and filter was $400 delivered.
As you say, not cheap. Are there any Dellortos around?
I guess these would be off Ducatis and therefore priced out of reach too. I will ask around. Keep looking.
Cheers, John |
125 RIDERS' ALLIANCE
A wise person simplifies the complicated, a fool complicates the simple. |
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Ben
Honda CB350 Racers Promotion - Moderator
Victoria
288 Posts |
Posted - 20 May 2008 : 4:32:09 PM
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Thanks John, I will keep looking as well.
Let me know if you happen to turn up a rolling featherbed as well 
On a different, but related note - can anyone explain to me how to determine the correct carb venturi size according to intake valve diameter? Or are there any "thumb rules" out there? I have heard that the venturi should be around 80% of the valve diameter.........
Cheers.
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razer
Level 1 Member
New South Wales
5 Posts |
Posted - 13 Sep 2008 : 8:49:31 PM
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Hi fellow's this info may be a bit late but I have just purchased a pair of vm38 mikuni's from the US for $310 delivered.
Cheers, Ray |
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