XTZ 660 3YF Idling issues please help!!

[Flight666]

HI all well briefly I bought my 1993 XTZ 660 as a project and to restore and have fun with after a 20 year break from biking. Anyway I`ve stripped cleaned the carb and set up as per the manual. Also I gave the bike a full service.. I havent set tappets/timing as at the moment this is beyond me. The issue is the bike starts fine (ish) but the revs are lumpy and seems happier at 1500rpm-1700rpm tickover. To ride the bike is great pulls quickly and without issue through the rev range no hesitation at all and the engine sounds fantastic very quiet changes gear great but on tickover the idle is lumpy and stalls easily. re-start and the same again till it stalls anywhere from, 30seconds to a minute but does improve when engine is warm. The bike is all stock apart from a Micron tail pipe. Any help very much appreciated..many thanks in advance Nick

[xtzrick]

Hi Nick


Possibly fuel starvation or an air leak.

Are there any cracks in the carb mounting rubbers?

When you cleaned the jets did you use a carb cleaner spray?
I had to soak my pilot jet in carb cleaner then poke through with a bristle from an old toothbrush to remove the old petrol varnish.

Tickover is meant to be 1250-1350rpm.

To do the valve clearances take the seat, fairing & tank off.
Remove the ignition coil & tappet covers (the manual says unbolt & lower the radiator, I just use a bent feeler gauge )
Remove the center plug & brass screw from the left engine casing then turn the crank anti-clockwise until the "T" mark is inline with the notch in the crankcase cover (it's the single line that appears after the double ignition marks).
Check there's play in the rockers so you know you are on the compression stroke, turn the engine through 360degs if no movement.
Inlets are 0.10 - 0.15mm
Exhausts are 0.15 - 0.20mm

Rick

[Flight666]

Hi Rick Thanks for the welcome and the info

Are there any cracks in the carb mounting rubbers?
To be honest I never really gave that a great deal of thought I will double check next week although I didnt notice anything obvious


When you cleaned the jets did you use a carb cleaner spray?
I had to soak my pilot jet in carb cleaner then poke through with a bristle from an old toothbrush to remove the old petrol varnish.

I stripped all jets out and gave everything a very generous dose of carb cleaner and blew everything out with an air line..then repeated again.but no I didnt poke anything down the jets at all..I Set float and pilot screw as per manual again same with the plunger/adjuster to 6mm etc


Tickover is meant to be 1250-1350rpm.
This would be nigh on impossible at the moment. I did notice once everything was hot and after a quick ride around it did idle a bit better ie without stalling



To do the valve clearance
Could this affect my issue at the moment. I didnt want to start to many things at once (cock up a few jobs and try and backtrack things) as the bike was bought with this idling/cutting out issues Previous owner thought it was maybe an engine cut out switch issue then gave up . I did open up the switch and give a good clean out with electrical cleaner.
I did find the neutral switch was duff so replaced that. The bike does start and run better now I`ve done the above work. Just need to sort out this issue before I move on to other jobs around the bike.. The bike was a £500 buy off e bay and I bought it to learn and as a long term project..Thanks again ..Nick

[xtzrick]

Valve clearances are unlikely the cause of your stalling problem, the problem would get worse as the engine got warm.

Rick

[Flight666]

Thanks Rick I will leave those alone until I solve the idling issue. As it definitely got better as it got warm infact I`m very surprised how well the motor sounded and how well the bike pulled through the gears it certainly had some grunt (I was a 2 stroke fan as a lad and never ridden a large single) will start by looking for air leaks..thanks again

[Elbetzzz]

Same thing here. The bike starts well, but when idling at 1500 or lower, the revs are not constant, and suddenly stalls. There's a little "click" sound, before stalling. When idling at 1500-1700 the "click" is still present, and the revs go lower but it keeps running. The bike is happy at 2000 rpm. Any ideas?

Greetings from Mexico!

[donnybach]

I’d look at two areas. Stator and carb. As it’s low revs it’s pilot jet or pilot fuel screw (if all the carb is correct and clean). Easiest and cheapest is adjusting pilot screw to nicest idle and low running.
Sometimes a sticky float needle or float height.
I was chasing a carb fault around for ages, before Mezo suggested the stator. It was earthing so the pick up for the spark was weak. New stator, new bike.
Test the stator, clean carb and reset to factory settings for your place and it should be fine.
Unless this is where you tell me it’s fuel injected?

[Elbetzzz]

hahahaha, no no... it is carbed off course. thanks for the tips. I'll look into it. Hope it's not the stator. I guess the manual settings (2.5 turns out) are for sea level conditions, right?

Cheers!

[donnybach]

Usually yes. I upped my jets to the larger listed size (150 and 48 pilot) due to the arrow can and open air box, but not sure I’ll keep them. Problem is I’m now comparing it back to back with the 700, and it feels tiny and underpowered. Still love it though. Bet the 660 pulls a lot better.
Stator change is not a bother. Just about £100 for the 600. Electrex. Fairly quick job. Only mess about was crimping the new terminals on.

[Elbetzzz]

will the 600. Electrex. fit on a 4my? i guess it's the same as 3yf, right?