$4 gallon gas, thinking of leaning out mixture

[Tigerboy]

With gas over $4 a gallon now for hi-test (and my Baggy loves Hi-test due to the better mileage I get), I'm seriously thinking of leaning out the fuel mixture at the expense of some performance. Right now I get about 45-48 mpg on the high test, depending on how I ride but that's a pretty fair average. I have the performance M4 can, which came with my bike and my guess is, the carb was jetted accordingly. If I had to guess, the Baggy with stock can (the unusual car-muffler shaped one) gets about 55-60 mpg. I'd like to keep the M4.

I see from the exhaust (sooty black) that I'm running a little rich, and I can probably gain a few mpg by leaning out the mixture. Do you think I could benefit from lowering the main jet a notch, or should I rejet, and if so, with what? I'm willing to give up some performance for better mileage because I see my bike as more of a means to get from point A to point B rather than going to the track and racing.

Or maybe I should just leave things alone.

[basser23]

make sure the air filter is clean....and possible add some Seafoam to the gas to clean the whole fuel system..then see what ya got..
I am a believer in if it aint broke,dont fix it, till it is...try a slightly hotter plug as Bill J recommends..instead of a ngk 9,go with a 7or 8.

[mpact]

If it's running well, i'd leave it alone. We're paying around $10 a gallon here in Ireland and i'm pretty sure that's the cheapest in western Europe so don't feel too hard done by.

[basser23]

yep pricey in uk too.but remember,1 imperial gallon is bigger than a us gallon ...still I dont think there is a sound reason for it....in UK it's tax,here too in US

[iceman]

In Europe close to 50% of the cost of a gallon is tax !
We should catch up in the next four years.

[djsbriscoe]

If you can buy any because of the Government inspired panic buying of petrol after a threatened tanker driver stike. People just have to stock up on fuel for their Easter trip to the M25 car park.
Pity we cant fit diesel engines to our bikes and buy biodiesel at £1.25 a litre instead of £1.60. Petrol here is around £1.50 a litre here at the moment.

David.

[ajwebonly]

If it's of any interest UK price is currently around $8.53 / USG. Enough to make your eyes water.

[mincehead]

Noting this thread reminds me of a question I want to ask, what are the stock jet sizes for the primary and secondary (Tekei) carbs for the MuZ models please.
I will shortly be fitting a modified Skorpion replica exhaust to mine and won`t be using the restrictive Sebring stock cans so intend to jet up accordingly.

So pilot jet=

Main jet primary carb =

Main jet secondary carb=


Thanks in advance.

[DAVID THOMPSON]

i am also interested in what was the stock size jets as mine is a gas hog
It had an after market can on it just before i got it
now back stock but doubt the jets got changed back..

as i go 90 miles and am empty yes its that bad
dave

[mincehead]

Wow, that IS bad. I can go near 160 miles on a tank of fuel at motorway speeds (and above).

[Bill Jurgenson]

so this is for all XTZ engine including the MZ
primary main jet 130
secondary main jet 163
primary needle 5D963/5 (third of 5 notches, i.e. in the middle)
secondary needle 5X7C 3/5

here from the SZR handbook, the exact same carb but with a 140 primary main jet.

from the german page you see that the last Tenerés had a smaller main jet, 122, to better comply with CO measuring. You can safely try that and it should improve mileage.
Changing to a Mikuni TM34-B65 flatslide will get you much better mileage and performance as well.

[mincehead]

You`re a star THANK YOU Bill.

[djsbriscoe]

Before I order a Mikuni TM34-B65 from Kedo

http://www.kedo.com/products/30230.html

Could someone list the jets fitted to this carb as standard (as above for the OEM carb).

I've asked Kedo and they wont commit themselves when asked will it fit an MZ Skorpion without changing the jets.
I know it will fit physically (I believe you Bill and others) and will work, but is it plug and play (I know I have to change the throttle cable plate).

I don't mind rejetting it if I have to but it would save time if I could get the relevant parts at the same time as I buy it.

Call me over cautious or just lazy for not reading ALL the relevant posts if you want.

I have not found a definitive answer as to if this carb needs rejetting.

David.

[Bill Jurgenson]

the carb has no standard jetting. It sepends entirely on where it's to go.
Buy it from Topham:
http://www.mikuni-topham.de/ENGLISHSITE ... glish.html

he is the expert. Kedo gets theirs from him just like I do.
Tell them what it is for ( whether stock or tuned and how, not just the make/model) and they will set it up properly.
Steve Topham is heavily involved behind the scenes with many of the XTZ engines used in the ESA with dynotesting and mods. He knows alot about our particular beast firsthand.

that said, for a stock Skorpion with airbox or pod filters
115 left 125 right, 25 idle.

open with stacks one number larger mains,

[djsbriscoe]

Thanks Bill I knew I could rely on you for the correct advice.

David.