www.zxrworld.co.uk

My totally standard L5 is playing up big time and after spending all day on it, i have no idea what is wrong with it.

It was laid up for 8 years, i have totally stripped the carbs (3 times now) and cleaned them and they are gleaming inside.

When you start it, it fires up, wont idle properly, even with the idle screw right in.

If you rev it, the revs hang at 3k and take forever to drop back down.

I have tried the pilot screws from 1 turn out to 3 turns out and it makes no difference.

Checked for air leaks, have put gasket sealer around the o rings to be sure.

If you start it for 30 seconds or so the shut off and feel the downpipes, number 2 and 3 are bearly warm, 1 and 4 red hot.

When it does idle you can pull the ht leads of number 2, number 3 cylinders (or both) and the idle does not change, but if you try and rev it with either of them out it cuts out.

I have checked for sparks on all 4 plugs and they are fine.

Stripped the cabs down again just now and they look perfect to me.

Have tried balancing the carbs, but they just dont want to balance properly.

I have been riding it for the last week, it has some power,(struggles to reach 70mph) but stalls every time you come to a junction, i was hoping a dose of Redex would help, but i have done 200 miles on it with no change.

I have had the cam chain tensioner off and then refitted it, but the bike was never started while it was off.

Any ideas, i need it to get me to work?

have you checked the diaphfragm's for splits?

edl wrote:have you checked the diaphfragm's for splits?

Yep, all good.

Forgot to say, it was running fine before it was laid up 8 years ago.

sounds like a mixture problem to me

If 2 and 3 arent firing properly it might be the coil. Have you tried swapping the coils over to see if problem becomes 1 and 4. I know you have checked the spark but the coil (or the CDI) might be playing up.

masterofinsanity wrote:sounds like a mixture problem to me

Do you mean the pilot screw or do you think the carbs may still be gummed up somewhere?

Davw wrote:If 2 and 3 arent firing properly it might be the coil. Have you tried swapping the coils over to see if problem becomes 1 and 4. I know you have checked the spark but the coil (or the CDI) might be playing up.

Will try that, thanks.

My guess is frayeddying throttle cables for the revs hanging, and serious problems with the valves/shims.

Have you checked the clearences?

Davw wrote:If 2 and 3 arent firing properly it might be the coil. Have you tried swapping the coils over to see if problem becomes 1 and 4. I know you have checked the spark but the coil (or the CDI) might be playing up.

That sounds like the best idea to try to me. Sort that first then see if it sorts anything else. Id also set everything to standard settings too than trying to problem solve with everything adjusted to god knows where.

Surely it could not be valve clearaces as the bike was fine when it was laid up 8 years ago.

I'll swap the coils over and see what difference that makes.

I'm not sure of the standard pilot screw settings, the manuals only show up to L3, but the Autodata book at the local bike shop says 1 and 3/4 turns so i'll use that.

bikenut wrote:Surely it could not be valve clearaces as the bike was fine when it was laid up 8 years ago.

I'd agree it does sound unlikely, but remember that materials do expand/degrade etc over time. I'm no expert, and know even less about the coil side of things, but the varying heat levels you described would definitely have me checking the clearances at the very least. You've already got most of it apart so shoving a few feeler gauges in has to be worth the time?

Go with what Dave w said and check the coils.It aint gonna be the clearences as they wont of changed with it sitting idle.

Will swap the coils this week.

Also, could perished o-rings on the pilot screws cause this?
Not checked them closely, but they are the original ones.

Update:

Have just swapped the coils over but the fault stays where it is, so they are okay.

Am stripping the carbs again for the fourth time

bikenut wrote:Update:

Have just swapped the coils over but the fault stays where it is, so they are okay.

Am stripping the carbs again for the fourth time

Sorry that didnt help but if the electrics are ok it must be the carbs. - make sure that number 2 and 3 carbs are:-

1) Getting fuel to the float bowl

2) That the float/ float valve is working properly - ie not flooding 2 and 3