HT lead and Spark plug caps - replace ?
- Thread starter aSTerix
- Start date
jfheath
John Heath
Mine failed on my first 1300 - just felt like riding on a bumpy road surface, but later I had to keep the revs high when going uphill or starting off.
The copper core of some leads had oxidized (Verdigris), some of the plug caps were showing the wrong resistance (4.5K and 5.5K) and the earth contact of the coil was suspect.
I bought one plug cap and a length of standard copper core HT lead to try to pint the fault down. Lots of testing and riding around slowly up hills and then moving the leads around to try to find which were working and which weren't. I had the one new cap and two lengths of fresh HT lead and rode it like that for a while without issues, and while I waited for the full set of leads and plugs caps. I decided it wasn't worth messing around and risking being stranded.
If they are working, they look good and the cap resistances are 5K ohms give or take a smidgeon, you're OK. I was riding through winter on wet, mucky salty roads for much of the life of this bike.
They are quite expensive to change all 4. But so was I on my 1100 and they never failed on me. Doubtless they would have at some point. Although they have an NGK code on the caps, there is no NGK cap that would do the job on the 1300. Don't know about the 1100.
The copper core of some leads had oxidized (Verdigris), some of the plug caps were showing the wrong resistance (4.5K and 5.5K) and the earth contact of the coil was suspect.
I bought one plug cap and a length of standard copper core HT lead to try to pint the fault down. Lots of testing and riding around slowly up hills and then moving the leads around to try to find which were working and which weren't. I had the one new cap and two lengths of fresh HT lead and rode it like that for a while without issues, and while I waited for the full set of leads and plugs caps. I decided it wasn't worth messing around and risking being stranded.
If they are working, they look good and the cap resistances are 5K ohms give or take a smidgeon, you're OK. I was riding through winter on wet, mucky salty roads for much of the life of this bike.
They are quite expensive to change all 4. But so was I on my 1100 and they never failed on me. Doubtless they would have at some point. Although they have an NGK code on the caps, there is no NGK cap that would do the job on the 1300. Don't know about the 1100.
Certainly on the 1100, you can unscrew the insides of the HT cap from the sparkplug end. There will be a connector, resistor and a spring fall out. Likely the resistor is mucky and the electrical connections mucky too. I scraped everything clean and greased everything on mine before reassembly. If I remember right, end to end resistance - that's cap>ign. coil>cap is about 25kohms.
Couldn't you find out by carefully touching exhaust tubes after a cool start?
Can you recall which grease you used for this purpose ?
Could have been axle grease or petroleum jelly - I can't remember! And... - I added a short length of copper mesh - stripped from some old aerial coax - to bridge the internal spring. Totally superfluous, but it gave me some comfort! A bit like a bypass....
We have added the coil and HT to the bypass list !A bit like a bypass....
I hadn't thought of petroleum jelly, thats a good suggestion
jfheath
John Heath
No. Not that I thought of doing that at the time.
The cylinders were firing, but the failure / intermittent fires started when it was put under load. To get it to do it reliably, I had to go uphill in a higher than normal gear. At normal riding there was an odd sensation that the road surface was a bit rough, I wouldn't have put that down to faulty plugs / leads.