Carb problems with saturno 500

[Husky]

Hi I m Thomas from Norway new member both here and at "I gotta Gilera".
I ve had a 89 500 saturno since 2001 and it has gone 16 000 km.
I have several issues, but my main problem is ( at least I m quite convinced it is) the carb.
I just can t seem to get it right. The bike coughs and spits when I accelerate. Not if I give full power but lets say I go on I higway and want to overtake a car smoothly (when engine is fully warm) relaxes a bit on the throttle first then give like 2/3 of power..cough cough and then it comes.It got better when I removed the accelerator pump , but then I also lost a bit "punch". It also coughs a lot when I want to go smoothly out of a tight rounndabout
If I accelerate fairly hard and then quickly releases on the throttle but not fully down it seem to choke for a split sec.
It has always been like this and I know the former owner had the problem too, but he was dead when I bought the bike from a mcshop.(it then had 2000 km).
The floats in the carb seemed to have been fiddled with so I did my best to get the float level in it to specified in manual.
It has the Dellorto that was fitted when new..(phm 40 something?I don t have the manual by my side )
when I sloooooowly give power from zero throttle in neutral gear, the revs drops and it runs uneven around 2000 rpm before it suddenly increases rpm when I reach enough throttle.
I have the needle on 2 nd notch..but I ve tried different without success.
I t also quite often gives a bang or two when I deccelerate from high revs with zero throttle(kinda braking with geardownshifts).
I could write forever but this should cover mainproblem. I tried to fit one of those fancy small airfilters, but then it got worse and it coughed black smoke.
I ve inspected the sparkplug, and it seem ok in color.
I think the place of the airintake is weird since I imagine the air must be very hot there just behind the engine.
I consider bying new carb, but don t know what to go for.
I f anyone can bear to read all this and have any suggestions, I would be very thankful.
I m also curious if removing accelerator pump can be harmful cause of leaner mix when accelerating.
yes..another thing...seem like the bike doesn t get enough fuel sometimes when gas level in tank is low..It sometimes stops and it need to rest. That was a terror before I adjusted the floatlevel, but now that problem also is creeping back. No problem with fuelflow from the tank or dirt in the carb as far as I can see...
Regards Thomas

[Joachim]

hmmm... sometimes it sounds like it runs to lean, sometimes like to rich

I suppose that you have checked the carb setting (see workshop manual)
The last thing would be to check if there is something blocked in the carb.
You have done a propper cleaning? Maybe with something like supersonic?

And do not forget the filter of the fuel tap (located in the fuel tank)

Good luck

ciao joachim

[Husky]

Thx for answer. Yes ..my headache comes from it seams it s to rich and to lean at same time. But thats possible I think if it goes f example to lean with little throttle and too rich when accelerator pump pumps in fuel.
Yes I ve done my best reading the manual and I find settings for idle screw, needle and float level. I m not a total newbie to maintenance, but I m far from expert.
I ll do a new clean on both filters and carb and remove the accelerator pump again and see how it goes(I haven t even heard of supersonic..I just use fuel ).sadly I don t have time to do it first couple off weeks . the spitting that comes when I accelerate from a little throttle up to 1/2-2/3 then went away last time I did it.thats not from a standstill but when I for example have 5000 rpms,rest the throttle till it s down to for example 4-4500 then give throttle again(not full)
that happens a lot during normal driving.
Do you know if removing the accelerator pump can be harmful in any way?
and ..I just use random adds I find on gasstations because of the unleaded fuel..should I stick to one brand? do you know if some are better than others?
Thomas

[pppdrive]

Hi Thomas,

Have you tried using lead replacement addition to fuel. I know that Castrol do one; Castrol Valvemaster Lead Replacement Petrol Additive; and other companies do similar. If your fuel is a little low on octain rating the lead replacement may help. I used to use it in my Saturno but no longer need to.
Paul

[Husky]

yes I use leadsubstitute adds . I have several different (because I seem to forget to bring it when I need to tank up. ) . I drive on 98 octane unleaded. I don t think thers anything wrong with the fuel and adds. my carb is just a disaster. The former owner couldn t get it right either.(I ve heard from a friend of him).
maybe I should try and buy a mikuni or something?

[Joachim]

or you should watch out for a standard DellOrto which might be much cheaper
There is no one close by which you could lend for a test?
Not that you will end up in even more problems with a Mikuni etc, because it's some other fault

As said before... cleaning

ciao Joachim

[CB]

Hi Husky

I would check ignition system also, including new spark plug (although it looks perfect) and checking high tension cable, plug cap etc. Remember that a weak mixture is more difficult to ignite than a fat mixture. The ignition system of the Saturno is not very powerful and can be sensitive to using spark plugs without resistor combined with plug caps also without resistor. This goes for all CD ignition systems!

Also check (or remove) the two valves in the petrol tank cap. There are two pressure valves there,- one for letting pressure out just before the tank explode when left in the sun, and one for letting air in just before the tank collapse.

I guess you are using standard exhaust system? as this can affect carb setting a lot.

Good luck
Christian

[Husky]

I ll try and look into all of it thx:)

[Joachim]

ciao Joachim