Dyno Carb Set UP

Rob H

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Does anyone know of anywhere in the UK who has a dyno and experience with vincents to set up the carburation on my twin?
 

vibrac

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My guy is in Aylesbury we added a 8mm boss to underside of exhaust about 6 inches out for the lamba probe (Comet) otherwise its no better than normal tuning, I guess for a twin it would need to be after the join unless you have two sessions/bosses one for each pipe
To be honest thats for Racing, you should be able to set up a road twin or single without all that dyno stuff. Main thing is to get those carbs opening spot on together, plenty of well known settings on the forum what ever carb you are on its not rocket science and you don't have to dodge the eco terrorists with silly settings (yet!)
 

macvette

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Hi,
The guy who has the Craven collection in Yorkshire had a Vincent twin which he used to sprint. There is a Dyno Jet guy in Malton North Yorks. Who used to set it up( or said he did). The dyno guy was located in a small industrial estate on the Helmsley side of Malton. You don't say why you need this done so what's up?
I used a Gunson carb balancer to set the carbs on the idle stops and two wooden kebab skewers under the slides to sync the carbs.
Mac
 

BigEd

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Hi,
The guy who has the Craven collection in Yorkshire had a Vincent twin which he used to sprint. There is a Dyno Jet guy in Malton North Yorks. Who used to set it up( or said he did). The dyno guy was located in a small industrial estate on the Helmsley side of Malton. You don't say why you need this done so what's up?
I used a Gunson carb balancer to set the carbs on the idle stops and two wooden kebab skewers under the slides to sync the carbs.
Mac
Why don't you synchonise the slides with the Gunson carb balancer? Does the scale not allow you to have the slides lifted off the throttle stops?
 

macvette

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Why don't you synchonise the slides with the Gunson carb balancer? Does the scale not allow you to have the slides lifted off the throttle stops?
I synchronise the carbs at idle with the Gunson to get a good even idle then sync the lift off the idle screws using the kebab skewers under the slides to sync the lift of the slides. The skewers are about 10 ins long and I can see both of them move as I operate the throttle ( it's series D). I find it a very sensitive way of syncing the slides.
You could do as you suggest but this works for me.
Mac
 

BigEd

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I synchronise the carbs at idle with the Gunson to get a good even idle then sync the lift off the idle screws using the kebab skewers under the slides to sync the lift of the slides. The skewers are about 10 ins long and I can see both of them move as I operate the throttle ( it's series D). I find it a very sensitive way of syncing the slides.
You could do as you suggest but this works for me.
Mac
I haven't seen or used the Gunson tool. I wondered if it could be used to synchronise the slides at greater throttle openings. I have used both methods, mercury gauges and a couple of drills. Both methods work. The drills are quieter.;)
 

timetraveller

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If the Gunson vacuum gauge is the same as mine then yes it can be used. I got mine many years ago to synchronise the three SUs on an 'E' type and have used it on the Vin as well. If it is the same as the one I have then there is a variable aperture for the interface of the tool onto the inlet of whatever carb type is being tested and this means that the amount of 'suck' being seen by the gauge can be varied. At some stage of opening the 'suck' will exceed the rate at which the variable bypass can be set. For checking the lift I use one of the motion blocks which fit into the rear brake arms. One always has those with one.
 

macvette

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If the Gunson vacuum gauge is the same as mine then yes it can be used. I got mine many years ago to synchronise the three SUs on an 'E' type and have used it on the Vin as well. If it is the same as the one I have then there is a variable aperture for the interface of the tool onto the inlet of whatever carb type is being tested and this means that the amount of 'suck' being seen by the gauge can be varied. At some stage of opening the 'suck' will exceed the rate at which the variable bypass can be set. For checking the lift I use one of the motion blocks which fit into the rear brake arms. One always has those with one.
The Gunson is the same as it has always been except it's all plastic now. You can find them on line for about £ 15. How do you use the motion block ?
When setting the idle, I find that you have to be careful in adjusting the aperture so as not to restrict the relatively low flow though the carb.
Mac
 

timetraveller

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Hi Mac, on mine the part which pushes over or into the inlet to the carb has two parts which rotate relatively to each other in order to alter the size of the opening. This has to be adjusted so that the small indicator which moves up and down in the graduated tube is somewhere in the middle. The Gunson can then be moved from one carb to the other, being careful not to change the engine revs, and then the carbs adjusted so that the 'suck' is the same on both carbs. At higher revs, where there is more gas flow, the variable aperture has to be opened up so that the indicator is still somewhere in the middle of its travel in the graduated tube, and then proceed as above. Because at this stage one needs to have the throttles opened one needs an extra person to hold the twist grip partially open or a device to do the same. I have also used 'colourtunes' (glass sparking plugs) to get the mixture right but do not know how these would work on modern fuel. Two Lambda sensors let into the upper parts of an old exhaust system would obviously be better but I do not have access to such a system. That would allow the bike to be road tested at a variety of loads and throttle openings but would require two handlebar mounted indicators to allow the rider to see what was happening while hurling down the road.:rolleyes:
 
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