Spark plugs

[Tim L]

Everbody is right.
I installed it last month and the Pamco electronic ignition is fantastic, my XS2 has never run so good. No fouling, no farting, and a definite improvement in starting and performance.
Now I have another problem. An addiction.
I have just bought another XS650 project bike offf of ebay. I just can't stop myself. The XS650 is like crack to me.

 

[lopejd01]

I just put new plugs in. I'm using autolite xp63's.

 

[XSLeo]

Wal Mart sells a two pack of the Autolight AP63 for $4.86. I have been using them for a couple years and they work very well.
Leo

 

[Christen]

I'm having some trouble with my left cylinder not firing, vibration and fuel consumption.
Some history: I bought this '75 XS650 B last August, site unseen (10,000 miles). It sat in a garage for 20+ years with gas and oil and brake fluid in it. Among other things, I totally cleaned the tank of rust and re-lined it with POR-15 tank sealer, rebuilt the carbs (using original main jet needles) & petcocks, replaced fuel and vent hoses, new coils (4.0 Ohm), points, condenser, plugs (NGK LB05EP) and wires (7mm), adjusted valves, gapped points and plugs, adjusted timing (timing light), balanced carbs (manual method-adjusted idle screw on each cylinder to stall, then both equal turns back to 1000 rpm). It kick stared and idled nicely and the plugs are both a chalk brown color, however after 150+ miles of local riding, it no longer starts on first kick and the left cylinder takes 5-10 seconds to fire. After the 5-10 seconds, it idles evenly at 1000 rpm. My first thought is to replace the plugs and re-trim the plug wires. My second thought is the left carb may have flooding / fuel flow problems (float level adjustment, etc.).

It's been 44 years since I had my 1971 XS-1 650, but I don't recall the vibration that this '75 has. 4000 rpm is very smooth, everything else below and above is a bit rough, (rear view mirrors are showing two of everything). I also think the bike is burning through fuel quickly and is slower than my '71 was. At 4000 rpm, I'm going about 52 mph in 4th and 62 mph in 5th. I'll check the fuel consumption over the next few weeks but I would be grateful for any thoughts on these symptoms from you who know the bike and haven't taken a 44 year break. Thanks!

 

[5twins]

Sometimes when you clean up old carbs that have been sitting a long time, you need to go back into them again after a short while and clean some more. I'm renovating an '83 that sat for 12 years. I've had to go back into the right carb twice already. Symptoms were similar to yours, bike would not fire on that cylinder initially but it would kick in after running a short time and revving it a few times. I found the pilot jet partially plugged, and the choke jet too.

 

[Christen]

Thanks for your suggestion. I'll check that carb and post results. Have a great 4th of July.

 

[5twins]

Looking at the service data chart for your model, I see a B8ES plug is recommended. If that's what you're using, I suggest changing to a BP7ES. The "BP" indicates a projected tip, which will give a better burn, and the 7 is a step hotter which will burn cleaner. All the early models up to yours call for 8 heat range plugs but it's become standard practice to run 7's. They also call for a standard electrode "B" type plug. I think this is mainly because they weren't making the projected tip "BP" type yet. You can get the NGK BP7ES plugs right at your local auto parts store for about $2 each. Get a couple sets since you're still shaking the bugs out of the bike. Also, I find the old stock ignition is rather tough on plugs. You'll want to be replacing them every 3 to 4K miles.

 

[xjwmx]

NGK BP7ES plugs right at your local auto parts store for about $2 each.

I think there's also a BPR7ES, with R for resistor. I might move my resistor from the cap to the plug for better long term reliability and a quick fix in the field where you can just strip the wire and connect it to the plug...

 

[Christen]

5 Twins, Check/clean left carb and new plugs. Got it, thanks.

xjwmx, Not sure I understand moving the resistor from cap to plug. If I install resistor plugs, do I need to change the plug caps on the plug wires?

Thanks,
Christen

 

[xjwmx]

I don't know if it would hurt to have resistor plugs and caps both, but you do need one or the other. I've had NGK resistor caps become electrically open a couple of times. I like the idea of being able to fix it in the field with a pocket knife and vice grips and maybe some duct tape... Resistor in the plug would facilitate that. Also, it seems like some of the more easily available (e.g. from walmart) plugs that fit are resistor plugs.

 

[5twins]

With your wimpy stock ignition, I wouldn't recommend doubling up the resistance in the system. In fact, with the points system, you really don't need any resistance at all. The manufacturers put it there to avoid interference with people's radio and TV signals. When I still had points, I switched to zero ohm (no resistance) caps. NGK makes a very nice one .....

That wimpy stock system can use all the help it can get, lol.

 

[xjwmx]

For our concerns, the resistor seems to be about kickback in the coil. A mechanical opening is slow and ragged unlike a firing transistor so might not cause that.
I wonder if their zero-ohm caps are made the same way but with a zero-ohm resistor, meaning they can go open too. I guess you could always get a couple of those lawnmower clips...

 

[Christen]

I got the following from Mike's XS 650 - Spark Plug Cap - 14mm - 90 Degree Elbow - LB05EP - NGK. I believe they are resistor caps. So changing the plugs and going with non-resistor caps may help but the fact that the left side firing is a slight problem may still be a carburetor issue. I'll make one change at a time top see if I can isolate the problem and fix.

Thanks again,

 

[5twins]

Yes, the "05" in the part number indicates it's a 5K ohm cap. The "E" after it indicates it fits plugs with a terminal nut. I prefer the "F" type that fit the terminal stud, the threaded stud left after you remove the nut. I think they grip it better.

 

[kiwi]

I change the resistor cap to non resistor. Look inside the cap to see if the brass plug connector is the screw type. If it is, unscrew it, remove the resistor part, and cut a brass screw the same length. Put it back together the same way you took it apart. Looks stock, and now you can run resistor plugs, which for me are easier to find. When I am at the motorcycle recyclers I always am on the look out for caps like that. Grab a few, and sometimes no charge. All is good.