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Discussion Starter #1
Hello all,
Any one used the new type 40mm Dell'Ortos with the black plastic tops?
I've built a TT2 using a 750 and the throttle pull is very stiff.
I've tried all the usual things, cable routing, softest slide springs and even spent the money on Venhill teflon cables. But they're still stiff. I have an old pair of 32mm carbs that I tried and they were much better.
Any one else noticed this?
Regards Graeme
 

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Chilehead
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I have them on my Guzzis. Yes, they are stiff. One now has FCRs, world of difference.

Try lighter springs, or a different throttle barrel.

Tom
 

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i have them brand new on my SS 1000 DS, pull is way too heavy,
FCRs are the way to go, with newer bikes at least, but there are other
nice del'orto carbs available for bikes like the TT750, the guy with the
loud bike blog has them on his.

cheers. :)




ah i should add that i was so brave to add a domino dual quick action
throttle grip, that bigger spool is a nightmare.

:think: ;)
 

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The carbs to have on a tt2 would be the Malossis.They are the ones with the big sexy polished bellmouth. They also don't have the accel. pump in them which adds alot to the force required to twist the throttle open.You can try some lighter springs[I seem to remember people using Mikuni springs at one point] but the problem is at high vacuum it can cause the slides to stick to the side of the carb body and not shut the throttle.I've got 41 Mikuni flatslides on my F1 racer and they work very well.
 

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Discussion Starter #5
Thanks Folks,
I've tried cutting down the softest springs that Dell'Orto have, and found that the slides don't close straight away from full throttle to closed throttle, causing some sphincter puckering moments!
I've removed the pump levers which has made it a bit smoother but still too stiff for prolonged cruising. (touring on a TT2?) It's not such a problem once it's up a mountain road though. It's the getting there and back.
It's a road bike so Mallossi 41mm's with huge bellmouths and no air cleaners is out of the question.
I'll have to save up and invest in a pair of Flat slides if they dont free up soon.
Thanks for all your answers, I wasn't sure if the stiffness was common to all these new type 40's or just the ones I have.
I don't recall my old bevel SS, or Darmah's ever being a problem with the old type 40's.
Reagards Graeme.
 

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Do you have a quick-action throttle? that will make the problem worse.
 

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Discussion Starter #7
Yes, quick action Domino. Yes, I know it's making things worse, but it looks so nice! I've put a standard throttle on to try and it's still stiffer than a 900 bevel's throttle with the original 40mm carbs.
Thanks for your advice regarding these carbs, I'll try a few more things and report to all here.
I can't see why the new black tops should be any stiffer than the original 40's. (same spring tension, same casting etc) Except maybe they need to run in a bit? I thought maybe it was the way the cables are routed around the TT's tank and frame, but that's not it. A fellow sugested slight chamfering the top edge of the slides? I'll report soon.
Regards Graeme.
 
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