Re: Needle shim modification
 

Yep.

:plus1:

Re: Needle shim modification
 

Me thinks you worry too much......or about the wrong things.

The bike school has NO reason to be making ANY changes to their machines....NONE.

Of course it doesn't ride the same with a different sprocket; that's the whole point.

By all means, if you don't like the altered gearing, go back, but if you are doing it out of some twisted notion that you might be "hurting" the bike somehow, forget it; it isn't.

Mine is not idling right at the moment. Do you think I should put back the 15T sprocket? :roll:

Re: Needle shim modification
 

(Warning, piling it on...) I don't know about the rest of you guys, but the bikes in my class ran ok, but beyond that, they were thrashed! No mirrors, gas tanks looked like used aluminum foil, bent bars, stuffing coming out of seats, chipped controls, etc. Each day, they would trot out 36 bikes or so, and inevitably four or five wouldn't even start, and one or two would give up the ghost duing the session. There were a couple of dirt bikes that looked like they'd been driven into trees. There was a little bit of jostling in the morning for people trying to get on the least piece of shit bike. "Hey, I rode that one yesterday!" "Well, I'm riding it today!"

(I, on the other hand, was sitting astride my brand new silver/grey GZ steed in pristine condition! Everyone else in the class had bikes that were too big to be used. Oh, the irony!)

Re: Needle shim modification
 

Those bikes in LA were probably impounds or stolen/police donations - my class in Florida had pretty much pristine Rebels and a few dirt bikes. All started, ran well, were not dented or beat up, and we had the same bike on day 2 as day 1.

Re: Needle shim modification
 

I did the needle shim mod yesterday. WOW! I wish I had done it sooner.

What a difference a little piece of steel in the right place makes. The flat spot in the power is gone, and I have more confidence in the bike. I may try an upgraded exhaust and new jet in the carburetor.

Kudos to all of the contributors on this topic. Well done!

:2tup:

Re: Needle shim modification
 

I'm interested in hearing how much your gas mileage drops. Most report a 10+ mpg loss.

:)

Re: Needle shim modification
 

I have read about that. I will keep track and send an update. :??:

Re: Needle shim modification
 

can someone tell me if after the needle shim it is necessary to open the air filter up for increased airflow?

Re: Needle shim modification
 

The reason I ask is that I just did the 16t sprocket mod and am having difficulty getting up the most simple of hills here in NE Georgia. I love the low rpms that I get with the mod but miss the little bit of power I got with the 15t in 5th gear. Will the needle shim help with this? What is the difference in this mod vs the "gz power increase" mod listed elsewhere?

Re: Needle shim modification
 

Well you may not be a good candidate for the 16T
.....OR......
you just need to "adapt" your riding style a bit.

IIRC, you can do 50 mph with no sweat in 4TH gear and even 60 for short periods. That gives you a jump on 5th and might solve most of your problem. You also need to learn to anticipate the hills and build up a little extra speed going in. I found that I could pull most hills in 5th but had to run it up to 60-65 going IN to be able to maintain 55 going up.

If you change to something like a K&N filter, you should consider doing ALL the power mods; needle shim, jet change and idle air adjustment........but even with all three, most folks don't notice much difference. If you are not experienced in working with carbs, I would recommend that you NOT try it yourself. The actual changes are fairly simple but getting it all back together right can be somewhat of a challange.

P.S. As there are NO hills to speak of in Illinios, my experience was on a trip to Atlanta. There were some places that I had to run in 4th.....but not many....if there was no traffic pushing me to go more than 50.