spark plugs

[gravelman]

hi guys just finished my boyer install on my xs2 havent put strobe on yet just set at facory setting started third kick runs nice feels tad bit on the retarted side but once i strobe it i will know anyways my question is i found my bike seems to like the b7es plug more so then the b8es but for some reason b7es are hard to come buy other then in resistor has anyone tried the crossover bosch w5cc?? ot would i be ok with br7es resistor plugs next question is mikuni round slides does anyone know if they fit the 72 xs2 and still let u use original side covers without cutting them up i tried the flatslides from mikes but they wont clear cause the carbs are spaced back so far and last questuion anyone ever figured why these things stall if they are below 1200 idle i have tried everything i thought the boyer may clear it up but it hasent sorry bout being long inded here thanks for ur help joe

 

[cra-z1]

I have not had a problem with the idle. I did make sure the carbs were very clean. New or good carb boots. JBM industries offerers them for the early models. Pay close attention to all adjustments. I did add vacuum ports to the intake at the flat spot on the bottom of the head. With these you are able to adjust the vacuum on each carb close to the other. My bike will idle at 900-1000 RPM. I have posted instructions on how I added the ports about about a year or so ago. Make sure your cam chain is in adjustment and your clearances are correct. I am also running iridium plugs and 3.0 OHM Dyna coil and Pamco ignition. I believe your Boyer gets rid of the points and advancer, right?

 

[gggGary]

Your won't idle below 1200 is most likely carburation related. Is your battery good? Below about 1200RPM the stock charging system will not keep up with demand and the bike starts to pull the battery down. Are your carbs synched, idle and choke circuits clear, correct parts for your year carbs installed? My XS's will idle well below 1000 when the carbs are set up properly.

 

[gravelman]

thanks guys ya the carbs are clean vales st 3@6 cam chain is perfect it will sit there and idle just lovely then just quits like u turned the key off no stumbling or flucuation just stops kinda got me baffled the bike runs and pulls hard no hikups just has its mood swings at idle
thanks for ur help i will keep tinkering joe

 

[5twins]

The idle spec is 1200 for these bikes and for good reason. If you set it lower, they can and often will just up and die for no apparent reason. There's nothing wrong with the bike, that's just the way they are. Wait a minute, you'll never understand this reply because I actually used some punctuation and proper sentence structures, lol. Here .... this is more YOUR style .....


..... the idle spec is 1200 for these bikes and 4 good reason if u set it lower they can and often will just up and die for no apparent reason there's nothing wrong with the bike thats just the way they are

 

[gravelman]

lol ya sorry bout the spelling and typing and sentence structure.but i just type as i think and it just comes out like that lol but thanks for ur help .but u are proply rite cause at 12 rpm it does work fine .its just odd how it does it u would think it would stumble and die but no it just shuts off just like u turned the key .buthey its a pleashure to drive in its stock form and where ever the bike goes its lots of attention and brings back the past for many people makes it all worth while thanks again joe

 

[glennpd]

I converted to 5/8 plugs to allow greater selection of "modern" spark plugs.


Pamcopete shared his knowledge re. sparkplugs in the following post:

"You may want to consider changing over to 5/8 Hex spark plugs instead of the stock 13/16 because of the greater variety of new plugs that are available in the 5/8th hex style. Here is a quick guide to plugs that are compatible. They are all resistor plugs, as are all new design plugs.

NGK Stock

FR4 5155
FR5 7373 (Hotter)

NGK Stock

BCPR7ES
BCPR5ES 7496 (Hotter)

Bosh Stock

FR8DPX 4202 (Platinum)

Bosch Stock

FR8DCX 7557
FR10DCX 7563 (Hotter)

These are 13/16ths

AutoLite #63

NGK BPR7EIX Iridium

NGK BPR8EIX Iridium ('70 - '72)

I have tested all of these plugs with the PAMCO ignition, of course, and they all work great, but the Iridium plugs actually produced a 4% increase in gas mileage, which equates to better fuel burn and potentially greater power."

Thanks to Pamcopete for all this good info. One great sidebar to this analyswis is that when you change plug wire caps to match impedance with old cap and sparkplug you do not have to mess with the nipple screw on the top of the plug.

In addition to this list NGK has a compatible Iridium plug "BCPR7EIX". I picked up 2 of these on Amazon for $7 each.

Glenn

 

[cra-z1]

Just checked my gas mileage and I am getting a solid 60MPG with the NGK iridiums

 

[5twins]

If you need these "fancy" plugs to make your bike run right then I think there's something else off in the "tune-up" equation. All my bikes start almost instantly, tick over like a Swiss watch, and rev from idle to redline without a stumble or sputter. All run just standard NGKs - but the timing, valves, carbs are all set correctly.

 

[cra-z1]

I agree the bike should run just fine with the std plugs if everything is in adjustment. Just saying the iridium plugs just give you a better fuel burn for optimum performance.

 

[glennpd]

If you need these "fancy" plugs to make your bike run right then I think there's something else off in the "tune-up" equation. All my bikes start almost instantly, tick over like a Swiss watch, and rev from idle to redline without a stumble or sputter. All run just standard NGKs - but the timing, valves, carbs are all set correctly.

Yes, I agree 5twins. With stock NGK plugs my bike like yours starts immediately, runs cleanly from idle to redline. I switched from stock plugs to the 5/8th variety to allow easy access to a broader selection plugs and potentially take advantage of more modern technology.

I bought and installed the Iridium plugs as an experiment and found "some" improvement in performance. For my riding style the difference does not justify the price difference. The longevity may justify the price but I cannot tell yet.