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Starting with a 10TT9

Submitted by jonathan_newton on Tue, 06/01/2015
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I have a query regarding best practice when starting an engine with the Amal 10tt9 carb. The knurled adjustment for air screw; is it expected to be altered during starting? I run without a kickstart and use a roller starter. The throttle position is crucial as such a large bore reduces depression around the jet so little fuel gets lifted. It occurred to me that the knurled adjuster is there for that reason; is that the case. I'm trying to get to the best setting so after initial starting and warming in the garage I can confidently bump it when on a run. Mag, valve,plug and fuel levels are all good, but I still find starting a bit indifferent.

Submitted by robert_tuck on Tue, 06/01/2015

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I have a bike with a similar carb and race cam,starting cold or warm needs the carb to be flooded till it drips fuel.The air screw is left alone ,I would tune the low speed mixture using a colourtune plug. You are unlikely to have much of a tickover and I think the enrichment device on the TT which looks like a choke (but is not!) is used to adjust the pull on the main jet at large throttle openings.Someone will correct me if i'm wrong.

PS !, The "air" screw isn't an air screw either. It controls fuel.

Submitted by david_cooper on Tue, 06/01/2015

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I notice some riders place the palm of their hand briefly over the throttle mouth whilst kicking over - to get a bit more suction on the fuel. Oddly, I've never seen this described in instruction books. It's as if it is so automatic that owners don't even notice they are doing it. Maybe it's worth a try? It helps on my mundane 16H but the 30 I've occasionally borrowed has a tt carb (and kick start) but can be a problem to start. I've not yet tried the hand trick.

Submitted by jonathan_newton on Wed, 07/01/2015

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Previously robert_tuck wrote:

I have a bike with a similar carb and race cam,starting cold or warm needs the carb to be flooded till it drips fuel.The air screw is left alone ,I would tune the low speed mixture using a colourtune plug. You are unlikely to have much of a tickover and I think the enrichment device on the TT which looks like a choke (but is not!) is used to adjust the pull on the main jet at large throttle openings.Someone will correct me if i'm wrong.

PS !, The "air" screw isn't an air screw either. It controls fuel.

Thanks Rob,Istand corrected a ontheairscrew,Iforgot. Thats why I ask thequestion of adjustmentof fthepilotasitisa method ofrichningfor a givendepression. The"choke" appearsto be anair controlthat increases or decreases the flow ofairthrough theprimary, thus varying the amount offuellifted. Thesecold morningsdont help either....

Submitted by jonathan_newton on Wed, 07/01/2015

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Previously David Cooper wrote:

I notice some riders place the palm of their hand briefly over the throttle mouth whilst kicking over - to get a bit more suction on the fuel. Oddly, I've never seen this described in instruction books. It's as if it is so automatic that owners don't even notice they are doing it. Maybe it's worth a try? It helps on my mundane 16H but the 30 I've occasionally borrowed has a tt carb (and kick start) but can be a problem to start. I've not yet tried the hand trick.
Hi David,I think the hand trick is as you say toincrease depression and pull fuel up. Byleaving thethrottleclosed you areeffectivelydoing this, though there is a naturaltendancy toopenthethrottle whenstarting. She will notstart with any amountof throttleopening. I think Ineedto fit aplate like on a cement mixer :)
Idiscovered that closing off theintake helps alot as I inadvertantly left anaerosolcap ( with aholein it) over theintake whenstartingit one day and she reractedveryquickly, thendied before it ingestedthething! So less air flow creates greaterfuel lift. Mythought ofincreasing fuelflowby altering thepilotthen peresents more fuel for the lowerrateof airflow??? I just wonderedifany one usedit as an adjustmentforstarting?
Cheers
Jon

 


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