Been awhile

[desert1]

Been awhile since I've been on here but I'm still riding mybike.....had a problem of a stammer on accelaration whichI solved 2 weeks ago and upped my mileage from 33 per gallon to 40 per gallon (imperial galon) how I did this was by replacing my main jet needles with newer ones; the old ones were actually worn flat on the side facing the air flow, the bike no longer stammers, accelerates smmoothly and a nice increase in MPG with no hi-speed lean issues oh, I also loered the needle one notch......other than this news I just ordered a new timing chain.....summer has been slow coming in Nova Scotia but I get out as much as possible.
Bruce
78XS1100

Really enjoyed the ride east this year Guys!

[skids]

Where did you get the needles and what were the part numbers?

how I did this was by replacing my main jet needles with newer ones; the old ones were actually worn flat on the side facing the air flow, the bike no longer stammers, accelerates smmoothly and a nice increase in MPG with no hi-speed lean issuesBruce
78XS1100

Really enjoyed the ride east this year Guys!

[desert1]

needles

Hi Sid
The needles came from my 79 special parts bike,the needles that I took out that were badly worn had no numbers what-so-ever, the ones I installed had an x and I believe an 8 on the top of the shaft; they are aluminum in color while the ones I removed had a brass sheen to them.....cant say if they were Yamaha stock or aftermarket butwhat a difference in performance and MPG....
Bruce

[Crazcnuk]

I think many people overlook the needles/tubes as a source of wear.

Mikuni itself stated that needle wear can occur in the BS34 carb in as little as 5000 miles.

I am using needles and tubes from MikesXS:

http://www.mikesxs.net/products-37.html#products

Needle 51X11
Tube 336-Y0

I am running in the high 40's low 50's fuel mileage wise.(imp gal)

[CatatonicBug]

Good to know! Is that the only set that will work with the XS11? They say on the description that it runs richer than the Y0 set. Is that preferred?

[Crazcnuk]

No, they have the regular pieces there as well, it just recommneds using the new part number. I assume because they work better.

As for the richness, you can adjust richer or leaner as you wish.

I think most our bikes are running far richer than they should already, because of the wear. These needles likely only compensate for the overly lean settings that were originally set up on these bikes for emissions reasons.

As I mentioned I am getting over 50mpg on the imp gallon, so they can't be that rich. (i am also running 120 mains)

[desert1]

Take a picture

In a future post I will submit a picture of the worn needles.....for sure worn needles would cause Xsesive fuel use.....The ones I replaced were probably ase old as the bike......Guys check your needles next time your into your carbs, they may need replacing and perhaps the main jet as well....have a good summer Guys.
Bruce
78XS1100