Jetting

[Bitten]

Hi All,

I need to replace my original MIKUNI VM38SS flat slide carby (original) as the slide is very worn and causing the bike to run lean. Also I want to get one with an idle screw and just make sure the bike is as good as it can be

I would like to order the correct jetting with the carby and if I can get some advice from the OZVMX brainstrust beforehand it may save me some time and money

So some questions...... (apologies for any questions that appear ignorant!)

1. The guys at Mikunioz said the replacement carby slide cut is a 4.0 (The original is a 3.0). I am not sure of what are the ramifications of this are - do I need to compensate with other jetting (a 3.0 will cost an additional $66

Standard jetting specs from the Clymer manual are;
Air Jet:                         2.5
Pilot jet:                       #50
Needle Jet                     R-0
Main Jet:                       #310
Starter jet:                    100 - Carb comes with a 40 but was advised not to worry

2. I have a GMC exhaust and muffler on it - will this impact on the above

Any advice or guidance would be greatly appreciated

Cheers

[Freakshow]

just buy a 38mm of ebay for $120.
the should come stock with a 3.5 cutaway.  all the other jetting you can get in Au for peanuts.
then again why not just buy a new slide or a second hand one thats in better nick.  $66 bucks to change over the slide ? thats bullshit and they keep the old one i presume.  bloody robbers.

How much is this all going to cost you ?  if its as dear as it sounds, i'd build you one here ready to bolt on if thats the issue.

[bazza]

4 instead of 3 slide lets more air in=leaner

[Bitten]

Thanks guys

And thanks for the offer Freaky, the cost of a new carby and jetting (excluding the 3.0 slide) from Mikunioz is about $270 + delivery.

I'm not made of money but it's not so much the cost but I just want to get this as close as possible to correct jetting.

Its a long story but I took the bike to a workshop to have it jetted correctly & fix some kill switch issues I was having (Beyond my level of expertise!) and they told me it was running way too lean as it was sucking air into the crank through the carby and possibly seals. On further inspection I found the cylinder gasket was crap (I used a paper one sent in a gasket kit and the original was rubber) evident by a flame and strong breeze coming from the area on kicking it over. I have just got a new rubber gasket and if required a spare cylinder that has been sitting on the shelf for a while so I am confident I can fix that issue but the workshop jetted it as rich as possible to compensate for the leak so now I want to fix the worn carby issue and get it all back to how it should be. as for the GMC exhaust system I wasn't sure if this would add further complexity to the whole jetting issue

Whilst I can handle the rebuild, jetting and electronic are like left handed Hebrew to me! so any advice is greatly appreciated