Jump to content
Sign in to follow this  

bike kills plugs

Recommended Posts

i posted before and fixed the bike up but this problem still happens

new piston

good reeds

yamalube 32:1

stock main

48 pilot

1500ft above sea level

02 yz250

clean air filter with filter skin.

runs fine and then it just dies, put a new plug in and its starts up. plug lasts an hour or so of trail riding and some logging roads, i am thinking electrical since it just started out of the blue. what should i replace first? i was going to take it into a shop but thaught i would ask here again first.

:lol::p

Share this post


Link to post
Share on other sites
i posted before and fixed the bike up but this problem still happens

new piston

good reeds

yamalube 32:1

stock main

48 pilot

1500ft above sea level

02 yz250

clean air filter with filter skin.

runs fine and then it just dies, put a new plug in and its starts up. plug lasts an hour or so of trail riding and some logging roads, i am thinking electrical since it just started out of the blue. what should i replace first? i was going to take it into a shop but thaught i would ask here again first.

:lol::p

I had a similar problem and the issue was the brand new aftermarket reed cage and reeds I installed (V-Force.) The reeds would not seat properly on the reed cage body. This caused the plug to be doused in raw gas all the time. The plug never got up to proper operating temperature and it eventually fouled after a couple of hours. When I switched back to the stock reed the problem resolved itself.

Share this post


Link to post
Share on other sites
i posted before and fixed the bike up but this problem still happens

new piston

good reeds

yamalube 32:1

stock main

48 pilot

1500ft above sea level

02 yz250

clean air filter with filter skin.

runs fine and then it just dies, put a new plug in and its starts up. plug lasts an hour or so of trail riding and some logging roads, i am thinking electrical since it just started out of the blue. what should i replace first? i was going to take it into a shop but thaught i would ask here again first.

:lol::p

This sounds like a jetting issue. Electrical system parts are expensive and probably will not solve your problem. How abotu your main jet and needle position. As mentioned before , how about the reeds???

Share this post


Link to post
Share on other sites

Your jetting looks ok. I would adjust your air screw as this is mostly the cause of spooge and fouling problems. How far out is the air screw?

Share this post


Link to post
Share on other sites

the reeds are stock and in good condition and so is the cage since i just replaced them.

i run 91 if i can;t get 94.

needle is on the second clip i havn;t changed that

air screw was 2.5 turns out. if i have time tomorrow i will do the Idle test in the faq.

i used to run the stock 50 pilot and changed to the 48. a few hours ago but it still happened.

someone suggested changing from a br8es to a br8eg what would that do?

Share this post


Link to post
Share on other sites

a br8eg will run a bit better responsive "suppsosed to be a bit better to less foul plugs but if you foul plugs constantly you will still foul them , if have ran es and eg plugs im my bike rm250 and i still foul plugs , its your jetting

Share this post


Link to post
Share on other sites

2 1/2 turns is getting out there. I'm currently running a 45 pilot jet and ride from 1000'-4500' without problems on my 06. The bike is pretty much stock. Main jet is currently 172 but will be change back to a 175 main when it cools down a little more. I would change to a leaner pilot jet and adjust to throttle response. If the bike bogs its too lean, adjust the A.S so that it runs clean.

Share this post


Link to post
Share on other sites

An FMF pipe and silencer also make the bike run rich. Is your muffler packing fresh enough? I'd try a 45 PJ, one clip position higher on the needle and a 175 MJ. But start with the PJ first. Try the 45 with 1 to 1.5 turns on the AS.

Share this post


Link to post
Share on other sites

I know fouling is normally attributed to plug temp. rating, jetting or other intake issues causing the plug to run cold but in my experience (five different bikes, same issue of around 3hrs out of a plug) NGK plugs of late have become very prone to failure of the suppression resistor inside them.

The way I found this out was by accident as my MZ used BR7 ES but the shop only had B7 ES so I bought that as the only difference is the lack of 'R' in the number meant no suppressor... It still runs fine hundreds of miles later & I soon "deleted" the R from the plugs in my other bikes and have had no plug fouling issues at all, even on my town hack scooter that does regular 1/2 to 5 mile trips in traffic and used to eat plugs for breakfast.

Share this post


Link to post
Share on other sites

Yup, jetting it is. My 06 250 almost made me a stockholder in NGK till I sorted out the jetting for my riding style. Sounds like pilot and main too rich for trails and woods type riding. Whats the plug look like colorwise, under the wet oily sheen?

Share this post


Link to post
Share on other sites

FYI, Another thing to look at would be float level. It may also be a cause of problem, but I would check it while changing the pilot jet.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×