More XR250 Problems!!

[RMcommando]

Hello again

i posted a thread not too long ago about some problems i was having with my xr. after much effort the problems were never rectified.

ever since i had taken the carb off cleaned it and put it back in there was an air leak. you could hear this when kicking it over and running. it cause the bike to cough, splutter and backfire and low revs and stall when idling.

i took the carb off and put it back on four times to try and sort out the seal. i even sealed it with heat proof silicon the makesure it was airtight. to my dissapoint the same a leak sound was there.

although it was not running at its best, it still went so i didnt hesitate to stop riding. one day i took it for a play in these swamp and when riding up a mountain. then rode it down a road. the bike was running bad as if the choke was on, loss of power and spluttering.

after that i took it home and it wouldnt start again. i checked the spark plug, it was black and smelt of fuel. i tried a new plug but no spark. there is power being generated from the engine because i checked it with a multi meter.

any suggestions guys? i am only at home for another three weeks and all i have to do is ride so i am very bored and frustrated at the moment. it is killing mewithout my bike running on these nice days!

cheers in advance

zoran

 

[SpeedyManiac]

It doesn't sound like an air leak. The sound was probably just the normal air sucking sound. If you had an air leak the plug should be white.

 

[TemeculaTim]

Have you checked your timing and valve adjustments? I had one of my XR's timing chain stretch and cause similar problems. I also would do a compression check.

 

[RMcommando]

Thanks for your replys.

Do you think timing and valve adjustments would fix the problem of no spark? How do i check the timing chain and compression?

Cheers

 

[Ol'89r]

Commando.

Valve clearance is one of the first things you should check. If your intake valves are too tight, it will cause air to blow back through the carburetors. Also, unscrew the spark plug cap off of the plug wire and cut about 3/8" off of the end of the wire and screw the cap back on. The end of the wire can become oxidized and weaken the spark. Inside the cap, there should be a little spring and resister. Take a screwdriver and unscrew the slotted brass screw inside the plug cap. Remove the spring and resister and replace the resister with a piece of copper rod. This will give you a hotter spark.

If the spark is still not good, remove the pick-up coil inside the right side cover. It is the little square coil that is mounted right in front of the crank pinion gear. These coils are susceptible to heat and can go bad over time reducing the spark output. If the insulation on the pick-up coil is cracked or split, replace it. These coils can check good on a tester and still be damaged.

Compression is checked by using a compression gauge that is screwed into the sparkplug hole. If you don't already have a service manual, you may want to get one.

Just my $ .02

 

[RMcommando]

thankyou very much Ol'89r, this should help me a lot.

 

[magneto]

Start with the easiest things first, check for a grounded kill switch.

 

[Yamadad]

Like has been said, get a manual and check your jetting specs. When the carb is off and apart, check the seals, slide and other internal parts for wear. If its sucked a lot of gunk, it may be toast.

Also not to mention, the stock XR carbs are junk. Either way it all could be the carb has given up. Check Al Baker's XRs only website for lots of info.

Everything said so far is good advice, I just thought I'd throw in another thought or two.