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jetting????

Posted: Fri May 11, 2007 1:44 pm
by lubricantpixie
i read a thread on the forum ages ago and a guy said he was running with out his snorkel into the filter, i thought about this the other day and damn its a good idea, as every turn you add into the system reduces the airflow through turbulence up to 25% so surely taking the snorkel out will make you 50% better?

This is what i thought, i took the snorkel out and put everything back together, then took her out for a spin. the noise was fantastic you can really hear it breathing, sucking in the air hard, i was a bit afraid i might suck some small children into the bike as i went past a local school.

anyway the only problem i have now is that if i open the throttle right up, she coughs and doesnt go. i have to gently ease the throttle on and its fine.

Firstly i am guessing this is because the carbs are set up to take a certain amount of air but with the snorkel removwed it is over efficient and so the mixture through the carbs is to airy and thats why it cant handle the throttle being full open.

please someone tell me if im wrong

Next if this is the case, all i need to do is adjust the carbs (re-jetting?) if this is the solution then can i do this myself and how, or is it best to put it in the garage???

Posted: Fri May 11, 2007 5:15 pm
by greengoblin
Welcome to a world of toad :smt003

I've been trying to get it right for AGES now... :smt009

Posted: Fri May 11, 2007 5:38 pm
by RedexRobB
Fact is you need those snorkels there, they smooth the airflow into the carb, without them i dont think it will run right at all as there is just the entrance to the carb which is all sharp edges, that wont bode well for air flow at all.

Posted: Sat May 12, 2007 8:31 am
by Northern ANdy
Rob, I think your confusing it with the trumpets. I think they mean the rubber snorkel down to infront of the filter.

Posted: Sat May 12, 2007 8:56 am
by RedexRobB
Northern ANdy wrote:Rob, I think your confusing it with the trumpets. I think they mean the rubber snorkel down to infront of the filter.
Oh right! A popular mod is to route the ram air tubes straight into that bit, i believe a few racers run that mod. Im guessing they sort the fuelling and jets with that no problem.

nice one lads

Posted: Sat May 12, 2007 8:37 pm
by lubricantpixie
yeah rob i mean the rubber snorkel into the air filter not the trumpets on the carbs, why would i want to take them off they improve the airflow.

thats what i was thinking, i was going to mod my hoover pipes and make a lid that fitted over the hole left by removing the snorkel with the vacuum pipes going into this to give optimum airflow, however how do i tune it correctly so it doesnt choke?

if i take it to the garage and get it re-jetted will this fix the problem?

Posted: Sat May 12, 2007 11:02 pm
by RedexRobB
I think your best bet is probably a dyno mate, they can monitor the fuel and air while they run the bike and can make a proper decision in the adjustments. Only thing with ram air tho is you cant simulate it properly on a dyno, but im guessing experienced people can deal with that?

Posted: Sun May 13, 2007 10:35 am
by Northern ANdy
some dyno's have the facilities for ram air simulation. Motrac in Ellesmere Port can as far as I know.

Posted: Sun May 13, 2007 11:02 am
by RedexRobB
Its probably just a large fan directed into the air ducts. Only thing with fans tho is they produce pulses of air with each blade rather than a constant flow. Air tunnels get away with it by sucking the air through rather than pushing it. Obviously you cant do this with a dyno but a fan probably does the job ok :smt001