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Twin Ruff running at high RPMs etc?

Ducdude

Well Known and Active Forum Website User
VOC Member
Gents I would like your input on a few questions that have developed on my Twin toady after a 200 road trip..

I have been riding the bike a lot these past weeks on avg of 200-300 miles a week and this week end was no different except...

Today in any gear when the RPMs are high say at 60-75% throttle the bike runs ruff and bucks...

At any nominal RPM say 80mph in 4th she is fine, but get on it and the issue shows.. It also does this in 1-3rd gear....

I got home at legal speeds and and had a look at the carbs and the adjustments at the air mix and slide position were where they should be ..
I dropped the main jets and they were clear..
I had good fuel flow into the bowls via each of the petcocks
Plugs were pulled and were the prettiest shade of tan I have ever seen on this bike with the FT plug just a bit more dark brown then tan:)
New plugs were installed
Plug caps were securely attached to the plugs

It still breaks up at high RPMs..

I am running a BTH with 932 32mm Amal MKI concentrics,,,
Plug wires are Mallory wires for magnetos and are 1-2 years old..

Where would be a good place to look next to address the ruff running at high RPMs?


In other news:
My 6Vdc Generator also developed a whine today. Could this be an issue with generator sprocket clearance that closed up or are the bearings in need or replacement? The chain is a tad on the loose side... It only whines when it accelerates at constant speeds she is quiet..

Thanks All for your input!

Cheers,
Eric
 

chankly bore

Well Known and Active Forum Website User
Non-VOC Member
Is your kill wire (or any other wire) near your plug leads? Have you tried isolating your kill wire? Old Choctaw saying- "70% of carburettor problems are electrical." Could also be any number of other things like fuel frothing at particular revs. We will all be interested in the answer. Good Luck!
 

Howard

Well Known and Active Forum Website User
VOC Member
Might be worth checking the carb synchro, mine is very fussy. I take the float bowls off and the main jet (sometimes holder as well) and adjust the amount of needle showing at various throttle openings.

I've just got my plugs the right colour after 40 years, and I read somewhere recently, with our new "petrol" they should now be white, not straw coloured!!

H
 

vincenttwin

Well Known and Active Forum Website User
VOC Member
Earplugs and in 20 years you will not need them. , is it rough. Running or vibration ,check your big end oil feed quill ,see if crank is rubbing
 

david bowen

Well Known and Active Forum Website User
Non-VOC Member
In the era they were built we run them for 500 miles, only adjust one thing at the time, else you will not know where you are, also check your adjustment on your primary chain being to tight can give this feeling
 
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Chris Launders

Well Known and Active Forum Website User
VOC Member
According to certain daily papers Polish get everywhere,coming over here stopping our bikes working properly.hoping to find some in my garage one day.
 

vibrac

Well Known and Active Forum Website User
VOC Member
According to certain daily papers Polish get everywhere,coming over here stopping our bikes working properly.hoping to find some in my garage one day.

Bit like those Elisabethan neck warmers getting in the engines .......
 
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