81gs450l carb rejet

[03svrider]

i have a mac 2 into 1 exhaust for this bike and need to know what jets to have the mechanic install. i knew a really good mechanic and he told me to just bring him the carbs and he could jet it pretty well. he has national dragbike racing records on his old kawi and does all the work himself but he's moved on from the shop he was at. i'm asking the people on here because i'm going to pull the carbs and have a mechanic do it and don't want to go through the trial and error to get the best result. i've read here where people said the bike will never be perfect if i try to go aftermarket exhaust and the stock exhaust would be best but i don't really care at this point. as long as the bike runs ok and isn't too lean. also, i don't want to try and learn carbs while doing this, i just want it done.

[doctorgonzo]

How big are the stock jets?
The dyna kit I put in mine changed the mains from 115 to 165 (for stock exhaust but pod filters). Probably the same or maybe less difference with exhaust only, but I'm not sure. You do need to know where you're starting before you know where to go though.

[03svrider]

i have no idea. they are stock jets though.

[tkent02]

Your mechanic should know.

[salty_monk]

I have read that flow on a MAC pipe is not that great so it may not need to be re-jetted at all....

Dan

[doctorgonzo]

I have read that flow on a MAC pipe is not that great so it may not need to be re-jetted at all....

Dan

At least a pipe can be found. I have a 1981 GS1000G and the MAC for the G says through model year 80. I am probably going to wind up getting one anyway at some point, but I may have to weld mounts, remove centerstand etc... I hate to buy it without knowing, but I am yet to find a 4 into 1 that lists the 81 G. I want a Kerker.

[bgmart450]

I have read that flow on a MAC pipe is not that great so it may not need to be re-jetted at all....

Dan

I have heard the same thing about the GS450 Mac pipes. I have stock on one and some funky setup on the other, so unfortunately I don't have concrete proof of this, sorry.

[03svrider]

I have heard the same thing about the GS450 Mac pipes. I have stock on one and some funky setup on the other, so unfortunately I don't have concrete proof of this, sorry.

how would i know? i don't want to hurt the bike running it without the right mixture. what could be damaged by running it without re jetting?

[03svrider]

how would i know? i don't want to hurt the bike running it without the right mixture. what could be damaged by running it without re jetting?

anyone???????

[Nessism]

Yes, you can damage the engine if it's running lean. Usually you can tell it's lean because it doesn't run right. Common symptoms are that the engine does not want to take throttle and/or feels like it's running out of gas - surging and hesitating.

Standard way to see what's going on is to do some plug chops. Run the engine in the throttle range you are interested in testing for at least two minuets and then remove the spark plugs; they should be tan color, if they are white they are too lean.

Good luck.

[03svrider]

thanks alot ness. you're always a gret help here