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moto64

20 to 24 ?

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Now that I finally have this TV200 running like it should I wonder if going to a 24 carb would help its top end. It goes pretty darn well but just seems to sort of peter out at the top of 2nd and 3rd. I seriously don't think there is any more adjusting to do with what I have. I have a 24 on my 180 V and it's great.

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At that point you're getting in to custom tuning. There is no factory 24 option. 

You'd need to replace the intake manifold and get a Dellorto PHBH 24 ( I think, that or a PHBL I can never remember) or Mikuni TM24.

Since you're going with the bigger carb you might as well go with the less restricted exhaust. Here's the rub, in my experience the TV200 gear box only likes stock or VERY tuned motors.

Anything in between tends to be pretty gutless and annoying.

I think you should get a beater LI and put a stupid fast build in it. That will satisfy the need for speed and not devalue the TV200.

 

 

 

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I can attest that the 20mm stock carb can get you going really fast if you get the right exhaust and free up the air intake (wire mesh filter, keep the hose and airbox, remove the air scoop under the seat) a bit.  I had an sh1/20 on my deanspeed 190 with a boomstick ds and my series III was really fast (maybe 70mph on the freeway).  I only switched to a phbl 24mm b/c I could not get the jetting (low/mid) tuned in for the expansion chamber.  The lack of a slide needle on the SH1/20 was the issue. 

I suggest trying out different exhausts short of an expansion chamber and increasing airflow, but leave on the sh1/20.

 

Here's the carb kit I bought.  http://jet200.com/catalog/product_info.php?products_id=2340

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OK thanks. I was just wondering . I guess it is going about as well as it could right now in stock form and really, the gearing is actually quite nice for these roads with the long 2nd and 3rd.

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The trouble with any carb or exhaust change is that most likely you'll need to grind the barrel out to match things. Not sure I would do that to a tv200 barrel. 

If you ever did decide you wanted to play around with the top end, I might shelf the tv barrel and start with a GP200 set up. You can get them pretty cheap. Then you can grind away guilt free! 

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I think I have asked this before, but is it the stock port timing that creates so much vibration in this motor ? I am learning to keep things towards the top of each gear. And of course , anything I did would be reversible.

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6 hours ago, moto64 said:

I think I have asked this before, but is it the stock port timing that creates so much vibration in this motor ? I am learning to keep things towards the top of each gear. And of course , anything I did would be reversible.

Did u install new motor mounts ?

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Since your main dissatisfaction is that the engine won't rev out in 2nd and 3rd, try a few easy and reversible things first, like allowing more air flow to the motor (metal mesh filter or cutting out the airbox stomach thing, and taking off the air scoop under the seat) then rejetting.   like this kit http://jet200.com/catalog/product_info.php?products_id=2337

If that's not enough, get a larger bore exhaust, but don't go crazy.

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Yes, that’s what I did on my tv200 cut out stomach in airbox and opened up scoop . I’m running sh20 with new Casa standard Sx exhaust 

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On 9/18/2017 at 6:16 PM, Mike Anhalt said:

At that point you're getting in to custom tuning. There is no factory 24 option.

Not exactly factory, but one of the Aermacchi's was fitted with an SH2/24 that requires minimum tweaks to throttle cable to fit. I did however, remember speaking to someone that had one fitted several years ago and was told, after a dyno session, there was no discernible differences between the SH2/24 and the SH2/22 apart from increased fuel consumption.

----

Changing the gearing, as noted above, would probably be your best bet. Following that, use a GP/dl exhaust without the restrictive 'mushroom' baffle that is found on the LI/TV/SX exhausts. The tailpipes are easy enough to cut out and remove (with the right tools), and you could convert it a 'clover' type so it would still look OEM.  

 

 

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