Topic: Fitting new 4-4 exhaust, rejetting?

[Nezhac]

hey all,

My setup is the following: stock airbox, stock carbs (as far as I know), 4-1 Jama Marshall deep tone exhaust. Runs well with the current setup, been tuned up several times, spark plugs are good tan colour, pulls way through the rev range, get about 45 MPG (no highway driving, mostly for fun, so push it a fair bit)

side note: do u need to actually disassemble the carbs to check jet size, float level height etc.?

I'm going to fit a 4-4 exhaust from David Silver (I've heard these repros are made by MIVV) there's a picture of one pipe attached, stamp reads:HMCB350F SL HM333

my question is: do I need to rejet and change float level to get the new setup running well?

thanks 

[ekpent]

In a perfect world you should be able to do fine with the stock baseline settings,jets etc for that set up.

[Bodi]

The only way to tell is to try it as is. The DSS pipes are reputed to closely match the stock system, so stock jetting should be OK with the stock intake and a stock motor.
What's unknown is if the PO rejetted for the 4-1 or any engine mods installed.
You can, I suppose, tell the jet sizes by dropping the bowls and inspecting them with the carbs on the engine. This is a bugger of a job though! Getting at the bowl screws is a challenge. Getting the jets out and back in - or seeing the numbers while they're in - even more challenging. You can not accurately set the float levels this way. No way to see the needle height this way.
I would try to get the bowls off to replace leaking gaskets, any other work on the carbs should have the stack removed.

[Nezhac]

Thanks Bodi, just the info I needed.

Good to know those pipes are close to stock setup, should make it easier
Guess I'll have to look into tacking the rack of carbs off for proper inspection then, and get a bunch more gaskets

Thanks 

[Danno]

it is unlikely that the PO did rejet since most of the 4 into one setups are actually slightly more restrictive than stock so I am with Bodi on this one try the jetting as it is if it turns out just a little rich then use a k&n filter should solve the problem but i don' think you will need to rejet and yes the only way to tell what jets you have is to pull the float bowl and look if they screw in you can unscrew them and look at them if they push in then get a small mirror and look if you take them out you will have a hard time finding the orings to put them back in you can tell they are push in because they will not have a slot or have a hexagon shoulder they will be just round follow the instructions to measure the float height in the manual