Topic: Problems after carb rebuild

[janne_83]

Cool! Huge progress after changing the rubber carb insulators! A lot better but still I have to collect the rpms carefully ’cause if I turn the throttle quickly, it’s not gonna build the rpms; it almost sounds like it’s gonna stall.

So I have to be careful raising the rpms and I cannot get past 4500 - 5000. This is really strange but I’m gonna test the old gas tube next. Probably I should mess with the mixture screws wadda ya think? I think that it’s not actually a mixture screw, rather a screw for the amount of gas, but which way does it work; loose-more, tight-less?

[janne_83]

Okay, think I’m very close now. I’m missing the parts 20,21 and 22 and I thought this wasn’t an issue since I’ve never owned those parts and the bike was ok before. But the old air filter was from K2 and it didn’t have a hole in the bottom like the correct K3 filter that I have now. So as I’m missing the parts 20,21 and 22 the engine is getting too much unfiltered fresh air from the tube of part nr. 19. I took away the filter and stuck my hand in to block the venthole and the throttle responded nicely just like it should and the revs came back. I did not have any idea that the air intake details make such a huge difference and that this would cause huge problems.

If I’m not mistaken it’s really common to have those parts missing and just own the part 19 so now I would like to hear what material you’ve been using to replace the filter element etc. I think it requires a material of specific density to get the balance correct.

Oh and btw. the breather hose is not connected to the air box, it’s hanging loose so also this is not like in the original setup

[Deltarider]

... I’m missing the parts 20,21 and 22 ...

Good.

... So as I’m missing the parts 20,21 and 22 the engine is getting too much unfiltered fresh air from the tube of part nr. 19. I took away the filter and stuck my hand in to block the venthole and the throttle responded nicely just like it should and the revs came back. I did not have any idea that the air intake details make such a huge difference and that this would cause huge problems. ...

Can't you just block that hole in the bottom of the filter element? Or use the old type CB500 filter element?

Oh and btw. the breather hose is not connected to the air box, it’s hanging loose so also this is not like in the original setup

Perfect, keep it like that.

[janne_83]

Can't you just block that hole in the bottom of the filter element? Or use the old type CB500 filter element?

The metal tube of part nr.19 goes through the hole of the air filter element so if I would block the hole of the filter I would have to leave out the part nr. 19 also. Probably the easier way would be to block the breather tube hole and the drain hole, both on the bottom of the airbox.

The old type filter element doesn’t fit perfectly and the old filter was smashed from the bottom by the part nr 19. The old type is paper all the way and no hole so the tube stucks inside the paper filter.

I think I should start to investigate the ways of blocking the breather hose connection and drain hole if this sounds safe and ok. This would have the same effect of blocking the hole of the air filter and this would mean no air flow at all from underneath the filter.

I’m pretty happy I did not open the carbs once again or start to play with the screws on the PD carbs yet, whatever they are meant for 😅