TOPIC:

Hello

I´m going to use this post to tell how can I tune up my nordwest to return it to the road

After 4 years forget in a garage, I did this:

-New cam belt dayco
-Rebuild water pump with high temp bearings and seal
-New oil filter and motul 5100 10w40
-New paper air filter
-Clean the carb and a pair of new gaskets from yamaha
-Adjust valve clearance
-New coolant
-Clean spark plug






After this, the nordy starts without problems, but they will come later...

-from 5k rpm, it´s become faulty, doing jerks and explosions through exhaust. I remove the air box and can see the second body of the carb only open 50% and keep shaking in this point. The spark plug is very clear, so it is running lean

-The gearbox doesn´t work properly, when you step down you have to do it very slowly or the gearbox dissengage the gear and keeps in neutral. it has no problem when you step up..

a question: how many turns have to loose the screw of mixture of the carb from the totally close position?

congratulations
Ok, the diva is not running smooth until now, but when you are through with all this little faults it will be a reliable bike. And you will have a lot of fun

For me it looks like a problem with the diaphragm in the secondary carb.
It should open and close smooth.
Unfortunatelly you wil have to remove the carb again.
First check if the diaphragm sits at the right place. Sometimes the little notch slips out from the right place.
Next would be to see if the rubber is hardened.
Maybe you will still get a new one. Maybe i can send you the number tomorrow (i have it not here)
Another solution is to soak the diaphragm in silicon oil for a few days.
Maybe it will become soft again... maybe.

The idle screw is somehow not common on this bike.
3 turns out +-0,5 is the right value.
Way more than usual on other bikes.

The problem with switching gears maybe the well known 'bottle opener' problem.
Try to see if the lever has the same travel way up and down. Just move the lever by hand until you feel the resistance. If you have a bigger difference it maybe that it can be solved by adjusting the bottle opener part.
If not.... are there still new parts out there?
If not, we should think about a solution to repair the worn out parts

ciao Joachim

thanks for your answer

I checked the diaphragm and it was in his place correctly and it has no cuttings or holes. The rubber seems soft to me, but I dont know how it was when it was new...

I bought a pair of gaskets from yamaha and they are very expensive, if I have to buy several other pieces from the carb, maybe it was cheaper and easier buy a whole carburettor, that isn´t very expensive as I seen

Next day I will do a video of the carb running. Are you sure that running the engine revving it alone it has enough vacuum to open totally the second body?

I will test with a vacuum cleaner if the carb is fully open

what you mean with :"The idle screw is somehow not common on this bike."? I refer to pilot air screw, not iddle screw. this one:


I dismantled the spare engine to see the "bottler opener" and I saw how it works but I didn´t see how can be adjusted... I will check the travel in my nordy and if it´s wrong I will dismantle the system and check it (I have to collect the oil what is new...)

kike_gsi8v wrote:

I bought a pair of gaskets from yamaha and they are very expensive,

Bad luck. For the carb there is a cheap set of gaskets available. Uuups i thought it was listed in the pattern parts list. It isn't. I will see if i can find the part number, for the next time

Are you sure that running the engine revving it alone it has enough vacuum to open totally the second body?

No i am not shure. I have never tested this
Just lift up the slider with your finger. It should move down very smooth, all the way. You can also blew into the oval hole on the back side of the carb, just on the upper end of the big hole. The slider should move without any sticking up and down. Some silicone spray wil be a good idea anyway.

I refer to pilot air screw, not iddle screw. this one

ouch.... that's because of my poor english.
We are talking about the same screw

...but I didn´t see how can be adjusted...

Last time i had adjusted something there is *years* ago.
Somewhere in the middle of the hole in the bottle opener there must be a little bolt with a nut.
You can loose the nut and adjust the screw. It is somehow 'excentric'
So you can adjust the pedal into the middle of the travel way.
But be aware, in most of the cases it's the bootle opener itself
If i remember right i have adjusted the lever first, but that did not last very long, so in the end i had to replace the bootle opener part.
Maybe you wil receive a second opinion from someone else here.

ciao and happy easter, Joachim

where can I buy this set of gaskets? yamaha? I see some sets through ebay but they don´t include the diaphragm. the bigger kit I see with all jets gaskets and o-rings costs aprox 70€ and if I spend a little more I can buy a whole new carb..

About the pilot screw, I made a mistake when I cleaned the carb and loose it completely until the spring get out and this is why I need to know how is the properly setup.

to be continued...

Hi Kike I have bought these Yamaha gaskets from Yambits and ebay shop before,
you don't want the kit with jets as Gilera's use different sizes to the XT600, I have one time found the 2 carbs where they are joined together to not be inline.
good to hear that you had it running now to make it perfect
John