1300 carbs on a 1200

[hell yea]

is there any benefit to fitting 1300 crabs on a 1200 our will it just run to rich ?

so if anyone has dun this what were the prows and cons ? .

Am thinking about rebuilding crabs debating weather to get the 1300 crabs to put on my 83.

Any advice appreciated

[Venturous Randy]

To go to 1300 carbs on your 83, you may also have to change your TCI to get it to run correctly. Look at your TCI, which is under the battery box, and see if the part number starts with 26-.

RandyA

[Stanman]

is there any benefit to fitting 1300 crabs on a 1200 our will it just run to rich ?

so if anyone has dun this what were the prows and cons ? .

Am thinking about rebuilding crabs debating weather to get the 1300 crabs to put on my 83.

Any advice appreciated

Just curious....why are you wanting to put crabs on your bike? lol

[Venturous Randy]

Just curious....why are you wanting to put crabs on your bike? lol

 

Stan, don't ask.

RandyA

[Yammer Dan]

Just curious....why are you wanting to put crabs on your bike? lol

 

Don't you get hungry when out riding?? Man just planning ahead. :whistling:No charge..Stephen.

[hell yea]

yep a lofe of bread and sum buter in the top box

but honestly is there aney benafit from the bigger carburetors

[bongobobny]

Never tried it but let's think about what happens. The pistons are only going to suck in a certain volume regardless of how much is available from the carbs. The carb's main function is to provide a controlled mixture of gas and air to the combustion chamber. It does not force any more into the chamber, only a blower can do that. The only way to increase volume into the chamber without using a blower is to increase the stroke of the piston which will decrease the maximum RPM the engine can safely reach without flying apart.

 

So, the short answer is I don't think so...

[Yammer Dan]

I got a nice little Turbo.....

[jasonm.]

86-93 have bigger main jets . Once you set the low speed screws properly. It will run a bit rich above 5000rpm. But really how often do any of us run above 5000 for more than a few seconds. The biggest advantage of the 1300 carbs is a slightly bigger bore 35mm vs, the 34's the 1200's have. And a bit quicker response with the 1300 slides. And a few other things...but of minimal importance.Such as the pretty carb caps on the diaphragms...1200 carbs have a sharp inner edge which causes the rubbers to wear out faster than on 1300 carbs. If you have a 1200. The edges can be wet sanded(rounded) back w/ 220 and 400 paper. It really does make a LIFE difference for the diaphragms. Just something I noticed having owned both. The TCI ...don't need changing. The advance curves differences from 1200 to 1300 is minimal...I think

[hell yea]

thank you

[dingy]

You will either need to change the TCI to a 84~89 model, or an Ignitech if you use the 1300 carbs. 83 TCI will start bike, but performance will be hindered.

 

The reason being is the 83 models used a vacuum source from a port on the carbs above the throttle plates. The 83 was the only year to have this port, other than California sold bikes which use a similar (different size) port for smog canister. The 84-93 bikes switched to using the carb sync ports on #2 intake manifold.

 

What this difference in vacuum source does is reverse the curve of the vacuum pressure. An 83 has near atmospheric pressure on the port when the motor is idling, then the vacuum reading rises as the throttles are open. The 84~93 bikes are the opposite, they have high vacuum on the port at idle, then this vacuum reading drops as throttles are opened. Ported & unported vacuum are the semi technical terms.

 

This difference was compensated for by a change in the 84 and later TCI's by inverting the way the circuitry interpreted the signal from the boost sensor, which is a pressure gauge that reads the difference in vacuum.

 

I don't think using 1300 carbs with intake vacuum on an 83 TCI will retard the timing, but it certainly won't advance it as it would if the vacuum source was to be above the throttle plates.

 

The 84-93 carbs still have the casting boss where the port was located. It could be drilled ans a port installed there.

 

As a side note, an 83 set of carbs can be easily used with an 84~89 TCI, simply by plugging the port on the #2 carb above the throttle plate and switching the vacuum line to the #2 intake sync port.

 

90~93 TCI's are very different and require rotor and pickup coils to be changed in order to work on an 83-89 motor.

 

Also a TCI from an 85~89 VMax will work on an 83~89 Venture, as long as vacuum is on #2 sync port. VMax's have a more aggresive advance curve, but will directly swap as far as electrical connectors.

 

Gary

[hell yea]

so vmax tci with vmax carbys i have all the vmax internals from a low mileage bike pistons rods heads cams inlet ect am debating wether to go with it at this stage.

Will venture headers fit up without mods and do pod filters work ? allways appreciate advice from the experienced

[dingy]

so vmax tci with vmax carbys i have all the vmax internals from a low mileage bike pistons rods heads cams inlet ect am debating wether to go with it at this stage.

Will venture headers fit up without mods and do pod filters work ? allways appreciate advice from the experienced

 

VMax exhausts will not fit a Venture. Venture mono shock mounting interferes with the VMax rear pipes. VMax's have conventional dual shocks. There is a chance that a Kerker header might fit. I have one here I was going to try to put on RSV, but it won't fit it.

 

Pod filters will work, they are usually used with a stage 7 kit for carbs. This mainly is either straight tubes in place of the VBoost manifold or running VBoost open all the time.

 

You should get on the VMaxforum.net and look around. Not a PG rated site, but in general, a fairly well behaved group. If you want to get power out of the V4, that is where I have found the knowledge at.

 

Gary