Spark Plugs keep fouling

[uknowme2goog]

I have 1980 xs and the spark plugs only last about 200 miles before there are shot. I am a using the factory plug NGK BPR7ES with a gap of 027-031. When I install a new set of plugs the bike turns over on the second or third kick and after a fewe rides it just gets worse...i have to kick it 20 times before it turns over...it has become to much of a work out...When i remove the plugs the normally white insulator is black and there is a little wet oil on the elextrode, other than that the plug looks finne.....sometimes if i clean the plug i can get a few more rides... What do think is the cause...

 

[5twins]

BPR7ES are not the factory plugs, they are the resistor version. You should be running the plain BP7ES.

 

[jayel]

you don't say what like of riding you do, short low speed, highway burner, ect but a oiled plug isn't good could be oil rings or valve guides if you're just short hopping you might drop a heat range BP6ES but keep a eye on they to see how they look after running

 

[uknowme2goog]

My local bike shop recommended that i use the BPR7ES because it was a better plug...in the shop manual you are correct.. BP7ES are the stock plugs.... Do you really think it will make a diffeance??? If so i can order them....

I do alot of short rides like 20 mins each way on the weekends...there was very little oil on the plugs...nothing crazy but still there....but why are the plugs turning black so fast?

What is the differance of the BP67ES plugs..are they better for short rides?

 

[jayel]

My local bike shop recommended that i use the BPR7ES because it was a better plug...in the shop manual you are correct.. BP7ES are the stock plugs.... Do you really think it will make a diffeance??? If so i can order them....

I do alot of short rides like 20 mins each way on the weekends...there was very little oil on the plugs...nothing crazy but still there....but why are the plugs turning black so fast?
What is the differance of the BP67ES plugs..are they better for short rides?

could be overly rich on the jetting, what are your jet sizes? your needle setting? what kind of gas mileage are you getting?

 

[uknowme2goog]

I have a set of MIKUNI VM34 on the bike. i guess the stardard jet size that came with the carbs..not too sure...Once the bike is running and warm the idle is fine..very smooth and will not stall...i was playing with the mixing screws and both screws are about 4 turn out from the bottom, both are about even...is that good or bad?...Gas mileage...i have no idea i have spoty tank on and 6 dollars of gas last me a while...any information on the proper mixing adjustment?...any one else use the other plugs BP67ES?

 

[Patches]

If I recall correctly the stock setting for those carbs is is three turns out from bottom. Also, what type of filter and exhaust are you running?

 

[jayel]

BP6(no 7)ES is one heat range hotter than the BP7ES the R in BPR plug(s) stands for Resistor you don't need resistor plugs unless you're running a radio or stereo it reduces the electricial pop you would hear in a unshielded radio system.... pilot screws are supposed to be about (damn just looked and Haynes says preset) but http://xs650temp.proboards.com/index.cgi?board=carbfaq&action=display&thread=730 guide says 3/4 turns out (will vary carb to carb) to properly sync carbs... if you are getting less than 45-50 mpg I would say you are running rich (black plugs)

 

[uknowme2goog]

Jayel.....I am going to take one turn off the mixing screws..three turns from bottom and see how she runs.

Patches...I have drag pipes...filter what filter...

I am going to get a new set of plugs without the R for sure...However, why do you think i should get to a BP6ES then an 7. You think i am running the bike to hot?

 

[jayel]

Jayel.....I am going to take one turn off the mixing screws..three turns from bottom and see how she runs.

Patches...I have drag pipes...filter what filter...

I am going to get a new set of plugs without the R for sure...However, why do you think i should get to a BP6ES then an 7. You think i am running the bike to hot?

NO the 6 plug is (runs) hotter than the 7, if you are short hopping the bike may do better with a HOTTER plug but straighten out your carbs first and try the BP7ES's first before going to the hotter BP6ES's

 

[uknowme2goog]

i just checked the mixing screws and they were about 2 complete turns from the bottom .. i readjusted the screws to three complete turns... also i checked both of the carbs idle doors and at rest they are open about 11/64". I used a drill bit and it slides in nice. Both doors are opening and closing at the same time my idle seems fine. Tomorrow i will change the plugs..keep u posted.

 

[jayel]

you really need to find out which jets you have in those VM's too, if they are Sporting for Less's VM34's they may not have the correct jetting for your 650

 

[Tomterrific]

You can use the BP6ES if you use premium gas and don't ride fast on the freeway. The #6 heat range will run hotter and burn off more of the carbon. A properly tuned engine works fine with #7 but in your case the #6 might get you better running. The R plug kills the spark energy, something in short supply.

Like has been mentioned. if you didn't get the VM34's from MMM at 650 Central you probably didn't get the correct jetting.

Do you run straight pipes? If I had a dollar for every poor running bike with straig.....

Tom

 

[5twins]

I don't hold out much hope for this guy. Several months back he couldn't find the sync nipples on his carbs even after being shown pictures. Now he's going to tune custom high performance VM carbs? I don't think so, lol, lol. He can't even understand the difference between spark plugs.

 

[uknowme2goog]

yo..5twins relax..not everyone is a xs guru...my carbs didnt have a sync nipple thats why i couldnt find them... so all the pictures in the world woulnt help me .. i understand the differance between the spark plugs now that a few guys explained it...

Today, i installed the #6 plugs and readjusted the mixing screws...seems alot better..the bike is starting on the first/second kick...when the motor is either hot or cold. The only issue now is that in 2 or 3 gear at high rpm's it feels like the bike is stalling or lossing gas and if i change to the next highter gear and the rpms lower and the bike feels fine...only at a very high rpm does it feel funny.. I have straight pipes...

 

[Panabikerxs650]

Im having the same problem with my 81 heritage special, dude did you finally fixed this issue?

 

[timbeck]

7 year old post.......
tim

 

[skidfrog]

BP6(no 7)ES is one heat range hotter than the BP7ES the R in BPR plug(s) stands for Resistor you don't need resistor plugs unless you're running a radio or stereo it reduces the electricial pop you would hear in a unshielded radio system.... pilot screws are supposed to be about (damn just looked and Haynes says preset) but http://xs650temp.proboards.com/index.cgi?board=carbfaq&action=display&thread=730 guide says 3/4 turns out (will vary carb to carb) to properly sync carbs... if you are getting less than 45-50 mpg I would say you are running rich (black plugs)

I just fired mine up for the first time in a long while with my Mikes XS 34 Mikunis. It was a tough thing to get it started.....but once I cleaned plugs.....let it dry out and tried again it fired up nicely. I checked the air screws and they were both out about two turns. I started over with just 1/2 turn out hours later once the motor had completely cooled and this time it fired right up second try. Pilot was recommended as a 15.....I'll have to look and see.