need help?

[cobraR]

i have a 1989 cr125r it runs good for about 1-2 hours but then it stalls out because i keep fouling out the plugs. When i remove the plug it is all wet. I am running NGK B8ES plug and my ful is mixed at 40/1 ratio. I have a FMF gold series fatty pipe with a DG shorty silencer on the bike which i am gonna take off and install a FMF silencer. I don't know if its something to do with the carb or the jetting please help thank you

 

[cr25096er]

sounds like it could be jetting. what jetts do u have in it?

 

[atc3434`]

Here, this is a link to Eric Gorr's article on jetting, that is on his website. You sound like you have to rich of jetting. Possibly a bad seal, but more than likely just some carb work is in order. Read that article. YES, that WHOLE thing. Then go buy some jets and get to work. ;) :confused:

Eric Gorr's Carb Tuning Guide

 

[cobraR]

i have the original jets in the carb. does my fuel to air ratio sound right or should i go to 50/1 ratio?

 

[Studboy]

cobraR, going to a 50:1 oil/fuel ratio will only RICHEN your Air/Fuel ratio (due to the higher spec. gravity of the oil). So, if you run 50:1 you will only aggrivate your problems, and possibly promote engine wear.
I suggest that you read Eric-Gorr's jetting guide (stated above) and get to work! As to my opinion on your oil/fuel ratio, I would be running at least 32:1 in your bike, maybe more if you race hardcore MX or something. A good rule of thumb is the higher the engine revs, the more lubrication it needs.

 

[cobraR]

thank you i been thinking about this so much what i mean't to say was 32/1 not 50/1 my bad. but thaks for the help. i guess i better get started on the jetting sounds like alot of fun.

 

[1999RM125]

Dont complain lol, i had to rejet my snowmobile... 3 carbs to drain and take apart!

 

[cobraR]

ok i looked up what jet settings my carb has. It said main jet is #152, slow jet is #55. where do i start i don't want to have to buy a whole lot of jets and ideas. i live in michigan and its just starting to get nice out now. 65-90 degrees. please help. also where is a good place to buy jets and do i have to get specific jets for my carb. oh one more thing how do i find out what size my carb is i think its a 34mm but i know there is 36mm and 38mm. could i put a newer carb from a newer cr125?

 

[Studboy]

cobraR, yes you could put a newer carb on your CR if you feel that you need more topend power and want to dump the money into the bike. I would start with the pilot circuit, go buy a #50 and #45 or so for starters, as soon as you get that figured out move onto the needle, then the main. Follow the jetting guide and you will be fine! You will be surpised at how much better your bike will run once you get it jetted at least in the ballpark. Good luck! :thumb:

1999RM125, I know your pain! My T-Cat has 3 carbs also, all in a rack. The best thing I ever did was rid myself of that impossible to remove airbox!

 

[cobraR]

what is the pilot circuit? also where is a good pplace to buy jets?