Dellorto SHA 12 clone on a 66cc HT

Discussion in 'Performance Mods' started by FelipeCobu, Jul 24, 2012.

  1. FelipeCobu

    FelipeCobu Member

    Hi,

    I do have a SHA 12 clone standing and was wondering if will
    it fit the requirements of my HT 66cc engine, I do suspect its too
    small, but if someone has a different idea could please talk to me.

    Thanks

    Felipe Cobu
     

  2. Fabian

    Fabian Well-Known Member

    I have tried the Delorto SHA 14 clone and didn't find it to be any better in performance or transition any better than a correctly jetted NT carburettor.
    I returned my Delorto clone to the Vendor and purchased other engine components.
     
  3. Chookawatts

    Chookawatts New Member

    Hi Guys,

    I have a real Dellorto SHA16 on my motor and it goes ok but I still had to jet it to #80 well its actually jetted to .793mm as thats the only drill bit i had, and it doesn't go much faster, but it gets to top speed quicker, it does 50kmh in 4th gear with 3 gears to go, but I only get 6 extra kmh from those 3 gears, in my opinion after spending a bit of money, these engines aren't worth spending a lot on, just get it to be as reliable and strong as possible, and have fun!

    regards,

    Chookawatts
     
  4. Fabian

    Fabian Well-Known Member

    When someone finally releases a small electronic fuel injection setup,,, our carburation problems will be instantly solved.

    Carburettors are yesterdays technology and rightly so!
     
  5. jaguar

    jaguar Well-Known Member

    Fuel injection is available right now if you're willing to fork out the cash.
    Dellorto not as good as stock POS Chinese junk? I strongly disagree. When I switched to a 12mm Dellorto it started easier, idled better, had more grunt, and gave me 6% more top speed.
    It will work on a stock 66cc as long as its not modified for much higher rpm.
     
  6. Chookawatts

    Chookawatts New Member

    Dellorto Carbs have been an excellent carb since I was a little boy, buy the right Dellorto carb for the right application wether it be race, performance or street and you will increase performance and reliability, but fuel injection will always be the best option!
     
  7. Skyliner70cc

    Skyliner70cc Active Member

    I don't think Dellorto clone carbs are worth the money. The stock NT Speed carb works just as well except in one area, starting. The dellorto clones start instantly.

    I'm going to sell my dax rt carb and go back to a speed NT carb. I need the ability to be able to drop needle valve height as I'm gaining 4-5000 feet in altitude over the court of a ride and you can't do that with a Dellorto clonse.
     
  8. jaguar

    jaguar Well-Known Member

    That's true. the Dellorto has no adjustment other than changing the main jet.
     
  9. FelipeCobu

    FelipeCobu Member

    I'm riding a my Dellorto clone now, It seems to be well all the power band but is way lean after 43 Km/H. Since I have new pistons rings on it I gave it more oil and will reduce the ratio a little and check how it behave. Else that, its fine too me. Will be working on a reed valve (from the AV-10 engine since its highly available here in Brazil) and perhaps it will need a bigger carb than this.

    Felipe Cobu
     
  10. Chookawatts

    Chookawatts New Member

    Hi Jaguar,
    I have bought one of your CDI's and I'm very happy with it but not sure which jumpers to use, I have left it as it came, but I'm thinking maybe I should be using the B2 jumper but not sure, your instructions say: use what runs best, but if we look at my setup, its a standard $129AU engine kit, not a grubee or DLL etc. it has an 16.16 Delorto SHA carb with a .793mm jet, a SBP expansion Chamber with a SBP muffler kit on the end, a rocksolid reed kit, a K&N type air filter, I ported the exhaust manifold to increase the flow into the expansion chamber, I fabricated and fitted a matched copper gasket, but the copper and silicon tube set up from SBP really needs to be replaced with one tube the right size and shape to keep the flow moving, which ill do this weekend, I have also fitted a jackshaft kit with a seven speed derailer, I shaved the head and completely removed the ring around the chamber, then fitted Stainless steel head studs and fabricated a copper head gasket, it has a B6HS spark plug, Ive ordered an iridium one from SBP, I have not done any port modifications, due to tightening the head too tight, the barrel wont come out without stripping the whole engine down, it runs sweet as it is and does 50kph in 4th gear, so far i cant seem to keep the revs up enough through the last 3 gear changes to get past 56kph top speed, in your opinion does this setup warrant the B2 jumper, and do you move the jumpers or add the jumpers? and thanks for providing us motoredbikes people with such a great CDI

    regards,

    Chookawatts

    PS: my original Delorto (not copy) was and still is missing the float bowl gasket, and I have had to order one for it, not a very good Quality control team at Delorto!
     
    Last edited: Aug 29, 2012
  11. jaguar

    jaguar Well-Known Member

    Click onto the Jaguar info link at the JNMotors CDI page to read how to test from scratch to see which jumpers are best. 54kph is 33.5mph which is about 8000rpm which is excellent for a Grubee engine. Be happy with it. Does it vibrate much? Have you done anything to lessen vibrations?
    My Dellorto came with the wrong size plastic sleeve so I know what you mean about quality control. I am going to try out a CNS carb next.
     
  12. Napper9606

    Napper9606 New Member

    I have the dellorto clone I guesd the dax rt and I lovr it! It sounds like a whole different engine now! Much quieter and if you tune it correctly with the right jet your golden. I have heard a tuned nt is nearly as good. Dont know why u would need a needle setting unless your going from extreme altitudes like previous post right?
     
  13. jaguar

    jaguar Well-Known Member

    Ideally you want a carb with ability to change the gas/air ratio for three different ranges: low rpm (idle air screw), mid rpm (needle jet by size/taper and height setting), high rpm (main jet)

    the Dellorto allows only a main jet change. I love mine but noticed that when top rpm jetting was right on, the low rpm jetting was lean. So I drilled another hole at the lower portion of the gas orifice column (see picture). Now the jetting is right on from low rpm to high. But what I really love about the Dellorto is that the gas enters the air stream at more than one orifice which means it is probably atomizing the gas better since if it only entered from one orifice it would be large and the gas would enter as large droplets. Entering via more than one means the gas droplets are smaller which means they have less change to experience till they are vapor.
    carbholes.jpg
     
  14. Chookawatts

    Chookawatts New Member

    Hi Jaguar,

    My engine is mounted using the SBP front mount and jackshaft kit, the fact that I've worked on cars a lot which all have rubber engine mounts, I thought it was normal to use rubber mounts, so I used heat/oil proof rubber in place of any of the spacers which seemed a great idea at the time until I realized the amount of movement the rubber spacers gave the engine was just enough to allow the chain to come off, and also made the engine cog side of the jackshaft kit chain loosen up enough to cause issues, I could have just put the Aluminium spacers back in, but I decided to fabricate proper chain guards with built in chain tensioners and it works a treat! chain stays where it should be, only problem is if it does come off the chain guards need to be removed to get it back on, but thats only 3 allen key bolts on one side or 3 screws and an allen key on the other, if you look at the pictures of my bike you can hardly see the front 2 chains. and you will see the chain guards i made.
     
Loading...