Fitting Bike Carbs- How Short Should Manifold Be?

[blessed6383 0]

im fitting gsxr carbs to my mi16 for now as moneys a bit tight (45's will come in few months)

 

1) how short should the manifold be cut? (standard mi16 inlet being used)

 

2)any idea's about joining?

 

3) how do i wire up the ignition and dizzy?

 

has anyone done this?

 

knew a guy near me said its been done a few times but i've never seen it done

[DrSarty 90 1 Cars]

I can chat to you about this later Chris when I come over, but you really should search as this is all covered on here in many topics.

 

Other topics also talk about management of spark and joining bodies/carbs to inlet manifolds etc, so it really is in here if you look for it.

[unariciflocos 49 1 Cars]

It's tricky business fitting bike carbs to an Mi16 for more than one reasons.

 

You need the float of the carbs to sit level with the ground and if you do that the carbs will just pop out through the bonnet. You can have them tilted a bit to the front and adjust the floaters a little higher to compensate, but it's the first step of the bodging process.

 

The only way you're ever going to fit them properly to the manifold is if you space them out from each other to exactly match the ports of the manifold. You need to make longer connecting pipes for the float bowls, get two longer connecting rods and make longer washers between the carbs out of some small diameter pipe. And extend the linkages of course.

 

After doing this you mate the carbs to the manifold and only use silicon joiners to hold them together. Just so that I make myself perfectly understood, the mouth of the carb has to be in direct contact with the mouth of the inlet port.

 

Trumpets are a must, got 187 Nm with no trumpets and 205 Nm with 6 cm trumpets. Same goes for the air filter, considering that these carbs use vacuums for everything you need to have the same pressure before all carbs. Note that I said air filter and NOT air filterS.

 

After this comes the jetting. Use these guides:

 

http://justkdx.dirtrider.net/printcarbtuning.html

http://www.factorypro.com/tech_tuning_proc...pm_engines.html

 

I ended up using 180 main jets for an AFR of around 13 at top range WOT and I would have had to drill out the main air jets quite a bit as I was running REALLY rich down the revs, but the engine decided to spin a shell before i got to do that.

 

Note everything I said is from my own experience, I may be wrong.

 

LE: Found a pic of my own manifold: http://forum.205gtidrivers.com/index.php?a...ost&id=7247

Edited April 25, 2010 by unariciflocos