Possible air leak

jas328sport · Post by **jas328sport** » Fri Jun 01, 2018 8:45 pm

Well it's all done and a massive sense of satisfaction, a bit of a ball ache to get the carbs back on and a couple of chewed up screws on the carbs that needed the chisel treatment but all in all not too difficult. I have not ridden it yet but it sounds lovely and smooth and idles really nicely.

jas328sport · Post by **jas328sport** » Sun Jun 03, 2018 1:08 pm

Scrub that as I have just taken it apart again,
I cleaned all of the jets with carb cleaner and blew an air line through them.
I then adjusted 3 of the pilot screws as the 4th was seized solid and the screw head was mangled where someone had obviously had a go at it before.
I then removed the inlet rubbers again and fitted them to the carbs first and then pushed them onto the inlets which I actually found much easier to do.
The results are that it now runs beautifully and pulls cleanly from as low as 1500rpm. No idea what I did yesterday other than do it in the garage which was a bit dark whereas today I did it outside in the sun so could see everything much better. I am thinking that perhaps the carbs weren't pushed on as far as they should have been.

jas328sport · Post by **jas328sport** » Sun Jun 03, 2018 10:51 pm

Arrgghhh this sodding bike, went out this evening and it ran perfectly for the first 20 minutes before it started missing on low revs again. On the plus side it feels way quicker than it ever has but I am getting really frustrated with it now though, I am sure that it isn't fuel related as surely it would start playing up straight away, I am convinced I must have a coil that is breaking down when it gets hot so I guess that changing them is the only way to rule them out.

jas328sport · Post by **jas328sport** » Tue Jun 05, 2018 4:54 am

Just one more thing that I noticed the other day is that my optimate was telling me that my battery is weak, it still turns over fine but could a weak battery mean a lack of power to the coils on low revs as it wouldn't be generating much of its own power on low revs would it.

Post by **Stig** » Tue Jun 05, 2018 7:53 am

A low battery won't help. My bike will cut out if voltage low

jas328sport · Post by **jas328sport** » Tue Jun 05, 2018 1:35 pm

Stig wrote:A low battery won't help. My bike will cut out if voltage low

Cheers Stig, I have ordered myself a cheap multi-meter from argos so will at least be able to check what voltage it is putting out.

jas328sport · Post by **jas328sport** » Tue Jun 05, 2018 7:18 pm

Well surprisingly it is still putting out 12.5v which I guess isnt too bad. The connections were a bit corroded so will clean them up but i dont think the battery is the cause. I have ordered a used pair of coils to try but does anyone know what the resistance should read on a decent working coil.

jas328sport · Post by **jas328sport** » Fri Jun 08, 2018 3:02 pm

So that's new coils and properly gapped plugs, new toobs, inlet rubbers, fuel and air filters as well as all jets cleaned.
If this thing still plays up when I try it later then it is getting a feckin match.

Teego · Post by **Teego** » Fri Jun 08, 2018 6:42 pm

jas328sport wrote:So that's new coils and properly gapped plugs, new toobs, inlet rubbers, fuel and air filters as well as all jets cleaned.
If this thing still plays up when I try it later then it is getting a feckin match.

Hmmmmmmmm.
Fresh fuel - Vpower to get it going?
Valve clearances?

jas328sport · Post by **jas328sport** » Fri Jun 08, 2018 8:09 pm

Teego wrote:
jas328sport wrote:So that's new coils and properly gapped plugs, new toobs, inlet rubbers, fuel and air filters as well as all jets cleaned.
If this thing still plays up when I try it later then it is getting a feckin match.
Hmmmmmmmm.
Fresh fuel - Vpower to get it going?
Valve clearances?

Well I have still failed to sort it, it runs absolutely spot on for the first 10 miles or so and then it starts to play up, the hotter it gets the worse it gets. It is at its worst when hot and in traffic and trying to pull away gently, as soon as you put it under load by feeding in the clutch you can feel it missing until it has cleared about 2500 revs and then it is fine. Anything over 3000 revs and it runs perfectly.
It has new fuel and I must admit it definitely ran worse when I put standard fuel in the other day as they were out of V power, I filled up again tonight with tescos momentum and it wasn't as bad but was still doing it.
The only things I haven't done are balance the carbs and get the valve clearances checked, maybe I should look into getting the clearances checked although I get no other symptoms of valve clearance problems as it starts straight away whether hot or cold or is that not really an indication of all being well.

Teego · Post by **Teego** » Fri Jun 08, 2018 8:22 pm

I remember when my exup had tight valves at about 35000 miles.
It was an absolute bastard doing hill starts. Had to rev the tits off it to stop it bogging down. It was fine at speed.
I had the valves done and carbs balanced and all was good again. But that's just my experience for what it's worth.

jas328sport · Post by **jas328sport** » Fri Jun 08, 2018 8:50 pm

Cheers mate I am, beginning to think that I am going to have to get it done if only for piece of mind as it has now done over 40k. I did have them checked many years ago and if I remember correctly there were a few that were a bit tight but at the time I was told that they weren't that bad. I have just watched a couple of vids on how to do it and it looks way more involved than I would ever be happy attempting so it definitely looks like a job for the pro's.
Any idea how much I should expect to have to pay to get it done.