tuning an xtz
 

hi people, after riding my bike from london to india ,the old girl is starting to misfire everynow and then and she could really do with a tune up, is it tricky to tune up these twin carby motors or is it a pretty simple procedure, should i just experiment with tips in the "pilot screw" post... its the twin carb thing thats got me a bit confused..

i was thinking of pulling the carb off giving it a thorough clean and putting it back on ( my choke is getting stuck on) im not sure if this is a good idea thanks boys...........phil..

[This message has been edited by futronix (edited 18 May 2005).]

First port of call fit a new plug. Cheap and usally does the trick. The plugs take a hammering on a single doing about 4x the work of one on a 4 o2 cylinder bike.

BD

Is it a 660?
Then adjust the pilot mixture screw.
And fix the choke plunger. Secret agent WD-40 usually does the job.
Check if the shaft of the shutter of the 2nd carb is worn out in the housing. Just look at it and then open the throttle about 6 mm. and see if the shaft first goes up and then turns. If that's the case you need a new carb or a miracle-job on the carb housing and the shaft. Symptoms would be irregular idle and a lot of explosions in the exhaust with throttle closed.
Don't take the carb off or apart unless you really have to. If you don't know what you're doing it usually doesn't get any better. Cleaning jobs usually only disperse the dirt. Just leave it where it is if it doesn't cause problems.


------------------
Fred, XTZ660, Holland.

ok, so i did pull the carb off just to work out what was going on but decided against pulling it to pieces just yet,a little bit of dust and grime but not bad considering what its been through.
one question has come from my fooling around...
to tune the pilot screw do i need a screw driver on a 90 drgree bend as the screw is on the underneath of the carb and very difficult to get into...or is there another way???

the choke was easy, wd40 and a rag...no problems.
a new airfilter has done wonders aswell...thanks for the replys, any more tuning tips HIGHLY appreciated.
i put a laser produro race pipe on this bike months ago but did not change any settings, bike still runs great, but do you think i should get someone to tune the old girl to suit the pipe...or can i do this myself????
thanks again....phil.(gotta love the xtz660)

I use a small screwdriver from a sewing machine with the plastic cut in half and a piece of rubber hose around the remains of the plastic.
Before you mount the carb, set the opening moment of the 2nd carb's butterfly. Put a 5 mm. drill under the 1st slide and adjust. Also adjust so that the butterfly opens fully horizontal when the 1st slide is open. And adjust so that the 1st slide opens exactly 100%, no less and no more.
Then when you have the idle mixture ok, get the bike on a Dynojet bench [or similar] to check carb settings.
And get rid of the Produro because amongst other symptoms it makes the 2nd carb hunt. It has too little volume for a 660. Try to get a Laser Duo-Tech. My torque went from 43 to 52 Nm.
Do upgrade the air hole in the 2nd slide to 4 mm. It gets you quicker throttle response.

------------------
Fred, XTZ660, Holland.

Fred, can you explain more in detail difference between Produro i Duotech? What is bigger advantage using Duotech and why? Why is volume of Produro too small for XTZ 660?

AnteK

If you look at the shear size of the thing and compare this with the size of the original one [which Mr. Yamaha has surely studied and found out that it was the best compromise in economy/power/silence etc] you can easily imagine that something is wrong.
On a Dynojet test run it turned out that the second carb was hunting because of the small volume of the end can. And the loss of power and torque when you mount the Produro is evident, especially in the lower revs.
The only advantage of the Produro is that it is so small that you have more space for luggage. If that is what you need.
The biggest advantage of the Duo-Tech is the increase of torque. And the idea to have a real exhaust with nice sound, either loud or silent, depending on which insert you use.
The Produro is either an absorbtion type, which is always too loud, or a reflection type which has no nice sound. The Duo-Tech [as the name says] is a combination of both.

------------------
Fred, XTZ660, Holland.

Thx Fred! Can you mail me some photos of Duo-Tech mounted on your bike? My real mail is ante.kardum@os.htnet.hr.

Regards,
AnteK

hello fred ,i have an xtz with that massive monster exhaust on it ,are you a mechanic if so can i get one of these exhausts fitted by you in holland ,i am an aussie and heading towards thailand and will be in holland area next week ,wood like some tips if you have any
david

David, it's not as simple as it seems because the piece inbetween the manifold and the can has to be made and/or modified. We have bought this piece from a FZR600 which fits on the manifold and on the can, but the curve has to be modified.
Furthermore I have tested the Duo-Tech in Morocco and the problem weas that it separates from the bike. That is, we haven't found the fixation yet that endures jumping the Moroccan stones.
But make sure you do come and see us next week! Where will you be? We are in Hendrik Ido Ambacht, which is near Rotterdam.

------------------
Fred, XTZ660, Holland.

well i got to say that ive yet to have any problems with my pro duro exhaust , however it is very loud... but it has certainly given my bike a huge increase in power and fuel economy, and yes the reduced volume is brilliant for panniers.
i bought the exhaust in england then road my bike to india with this can fitted.i thought it was brilliant.
im going to get my bike dyno tuned so i will let you know the results when i do...
phil.

hello fred xtz
i amcurrently in germany but willl be coming through holland next week ,around 20 th i think ,will you be around then at all
david

Yes, we'll be here. Let me know when.

------------------
Fred, XTZ660, Holland.