needle jets

Need to know the difference between the 4GZ11(SECA) and the 4GH15(maxim) needle jet. As far as i can figure out it has to do with time of transition between idle and main. The power band comes in quicker. Dirty

 

you are correct in your thoughts of taper transition. it has been said in the forums that yamaha did not publish the taper codes

http://www.iwt.com.au/mikunicarb.htm has needle info

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html more info sub links

i have read that the last number is the clip position if i find the link i will post it

http://www.iwt.com.au/techinfo.htm links to info

sorry i could not be of more help

 

There is no clip position on either of these needles. Dirty

 

Tried shimming but no positive result.

 

Found the 4GZ11(SECA) needle on Ebay for 12.00$ for one. Man these are expensive. How about that XJ4ever, what is the price. Dirty

 

1 for 21.95 or 4 for 79.95

 

The other option is to swap cams.
You won't be able to set them right by shimming. The taper is too dissimilar between the two.

 

he started by switching to seca cams then converting his carbs to seca
http://www.xjbikes.com/forums/threads/pilot-air-jets.76315/#post-487662

 

Well then (for perspective's sake) the cost of needles is not a huge deal. If it were me I'd look for a spare rack from a Seca. They run about the same price as a set of new needles and you get a set of spare parts along with.

 

Cant figure out why these needles are so more expensive than any other. Supply and demand i guess. Got the hanging idle fixed. The throttle response is good. I just cant get it ti idle unless i twist the idle screw between 2 and 3 up, then it idles high. Guess ill try the needles. The answer is here somewhere, just have to be patient. Dirty

 

So the only difference is the taper. Looks like the 4GZ11(SECA) had a steep cut while the 4GH15(maxim) needle has very little.

 

Are the emulsion tubes are the same on the maxim and saca. Smile Dirty

 

I am assuming you mean the idle knob in the back. on my maxim side cover it says idle is 1200 rpm which is different than the manual at 1050
have you running synced the the carbs yet?

 

on the wiki site page http://xjbikes.wikidot.com/carb-specs
for 81 to 83 maxim and seca
Main needle JET Size: #O-8 (the main needle JET is also known as the "power valve" or "emulsion tube").

 

Only difference i see is the Pilot AIR Jet Size: #170 and main jet nedle. Changed the model number for just for pilot air jet size and needle. The carb body is the body is the same.

 

Adjust the throttle cable at the grip.

Gary H.

 

Throttle cable slack is adjusted at the hand control, Idle RPM is adjusted at the carburetor.

 

so you have slack at the carb linkage?
this happened to me the po had the cable so tight to keep bike running, that when i rebuilt the carbs rpms soared

 

correct the pilot air jet and slide needle are the only differences in the carbs

 

I think he's saying both the cable and knob are adjusted.

Gary H.

 

You are correct Gary H. The SM states that the idle RPM (not idle mixture) is adjusted at the single adjustment idle screw between No 2 and 3 for the BS28 on the XJ550 maxim. The cable slack is adjusted at the hand control. As time progresses the cable stretches, hence the 3/8 adjustment at the hand control.

 

could be or was making a statement of where to do it

 

Yes.