1982 xr100 running rich, need help

[sm7482]

Frustrated please look! 1982 xr100 running rich, need help

hi im new to this forum, anyway ill start from the begening.
Im 14 and was given an xr100 for free because previous owner didnt need it. it didnt run cause they messed up the carb. after a while my buddy and i got it running but it smoked like crazy. i decided to do a restoration to pass time. i got it nice and proceeded with the engine. i had it bored to .50 new gaskets whole nine yards. i put the engine back in the bike and too my suprise it was smoking again. i tried the idle screw, pilot screw and it helped but still smoked. I talked to my dad and he said th float might be adjusted wrong. I started toying with it and it helped but still was either to lean or a tad to rich. I adjusted the float, pilotscrew and idle screw to the shop manuals specsbut its still to rich. I adjusted the valve clearence but did no good. The plug comes out chared and its not oil because the smoke is a gray black. am i missing somthing? clymer manuals arent really clear in that section. Ive been close but no go. any help appreciated.

might the points be dirty not supplying a strong spark?

 

[RM85rider123]

you should clean the carb very well and see if that would work

 

[sm7482]

ive already done that. ive soaked it in parts dip, and carb cleaner than blew it out with compressed air.

 

[RM85rider123]

ahhhhh, you made me remember, i had a 1994 xr100 and it smoked black a little. it only happened after i washed it though for some reason. it might be a problem with water or something.

 

[sm7482]

i guess, the fuel has been in the tank a while, everyone knows it develops moisture but would i need to rejet after the bore. it has a .50 piston now but everything else is stock such as the carb jets

 

[RM85rider123]

i dont think it would hurt, but I would have rejetted just to be careful.

 

[sm7482]

ill have to try. well it is my first bike so any information on jet sizes i could try? if its running to rich should i go biger or smaller?

 

[RM85rider123]

i truly dont know about what size you should switch to, you should ask somebody more smarter and mechanicly inclined than me, i know the basic stuff.

 

[sm7482]

me to thats why i came here. ive practically torn the engine apart and put it back to gether more times then ive riden it all for that problem. i know its probally somthing simple like the points too but i always over look those little things.

 

[BigRedAF]

Believe it or not sometimes a bigger motor requires smaller jets due to the increase in intake vacuum. That will cause more fuel being drawn in during the intake stroke.

That being said, I don't believe that your problem is the stock jetting. Those bikes are very solid. If your plug is black and you just had it rebuilt I'm puzzled. Your description is a bit shy on details.

You said black smoke so I'll assume it's not oil. You said you adjusted the valves, I'll assume they are correct.

You said it's lean or rich, sounds like you don't know.

Weak spark wont cause it to smoke!

Did you get a valve job or valve guides and seals?

They messed up the carb... What did they do to it?

Can you fix it?

If it's so rich that it's blowing black smoke and you can't adjust it take it to a shop and pay a tech an hours worth of labor to figure it out for you.

 

[sm7482]

well its running rich. the valves do leak a little and as for the carb they lost a couple parts like the main jet holder, you know the white piece that goes around it like a funnel, and messed up all the settings. they said it was rained on once but theres no rust in the engine or any wear cause of it. except the carb has pitting in the float bowl area and the carb body where the float is ill post a pic. it looks like it deteriated the main jet threads. They dont make new carbs either.

 

[sm7482]

well for missing parts, the main jet holder is missing, they also told me it needs a new float, suposedly it was rained on aswell but there was no water damage in the engine. the places where the jets scre into on the carb looks deteriated. i think water may have got into the carb but not sure, they lost some parts aswell so if any of you see aomthing i dont tell me please.
heres some pics