Sooty Exhaust

I know I ride dead slow not really going more than 40 anywhere but would this cause the bike to run rich ?, my tail piece seems rather sooty inside ?....not much of an A/F guru so over to you lot ?

Mine was the same when i was running the " by the book " jetting , you need to lean it down one notch , going by your riding style i would say the pilot jet and you could try to drop the needle down one slot and see how it runs , even better would be if you know someone with the proper equipement to get the jetting spot on .

Keep in mind that the most common jetting ( 68s - 3clip - 170/175 )  comes from the USA  so even at the same altitude the conditions over here are slightly different ( atmospheric pressure , humidity , temperature )  so the recomended jetting its just a guide to get you somewhere near ( and it works )  but as i and other UK owners have found out it is slighly Rich for us over here .

Even drilling one small hole in your air filter cover would lean it out slightly , so if you have a old one you can try it to see if it runs good   

Could I use the mixture screw to lean the bike out ?.....

i believe that it only affects the iddle circuit .

Yes, it would....
You see, you also have a rather (read: farging) short gearing, which probably means you ride 40 in 5th..... which is potting around, and zero offense pls.
The result will be that the engine doesn't get hot enough to burn clean/dry like the average hooligan's bike does.
Remedy it with a notch leaner main circuit (drop needle)?

Edith (n0 speling eror): leave the screw set at 'correct', you'll effect nothing by fiddling with it

USA jetting always seems to be excessively rich when in the UK? On my SE I had the head2wind kit which is the miracle cure in USA, however was WAY too rich. Similar to the BRP recommended jetting - I ended up dropping the needle a slot, and going to a smaller main (165) not the 170/175.

Are you running the right plug? Just a thought....

Stock plug and standard jetting from memory I think I dropped the clip position to 3 or might have moved it up.....sorry was a few years ago as she did a lot of popping on de-acceleration whatever I did seemed to virtually stop it .....she runs great just a sooty tip don't think she will get any harm done running rich ?, air filters clean and she normally starts first kick. Might drill a hole in the side of the carb so i can easily tell what position the clip is in ?.....  

Popping at deceleration is normal for XR i dont know why is everybody trying to " Cure it " , its a race bike folks it does pop and shoots sometimes no need to run it rich  

To try to remedy a sooty plug by installing a warmer one (ie longer insulation nose) is risky, and might cost you a piston - pls know this, and ESPECIALLY SO when we're talking 2stoke!!
Colder one may go but this obviously won't help.

Lean it out Maus, you don't use the WO circuit anyway.
Popping on overrun is normal, and if this bothers you then seal off the small leaks in the exhaust, the slipjoints for instance - a smear of silicone works well.

"Might drill a hole in the side of the carb so i can easily tell what position the clip is in ?"

Nope, not good enough - you'd need to make a hole in the slide then as well!
Come to think of it, if you do this on either side of the carb you could see through it, maybe a better idea as this would allow you to more easily communicate with your son who undoubtedly attends dad's spannering sessions so as to learn the correct way for later.




Ahem...   

Drop the needle one notch Mausie and see if it pulls better , and as Burpsa said if you dont like the popping sound you can seal the exhaust with this stuff , i forgott how you call it but its a special white paste for exhaust systems which goes hard when you heat it up , i have loads left from when i did my new exhaust install so you can have it if you want ( no jokes i am serious ) , Its funny that i actualy loved the racing sound /popping of my piggy  and never realized that if i seal the joint on the exhaust it will go completely silent    , but for those who like it silent its much better solution that running too rich and having big carbon deposits build up inside the engine ( no good trust me ) .

Sounds to me like it just needs a good run on the highway for an hr, stretch its legs..

That should clear things up.

Zoro wrote:Sounds to me like it just needs a good run on the highway for an hr, stretch its legs..

That should clear things up.

Ahhhh   another speed freak lol, I don't mind the popping as long as its not all the time....the XJR is fantastic at popping lol.....must make the effort and pull the plug after a normal ride and post a picture for you guys....plugs best way to get an idea of mixture surely ?.

Frost, you're certified mad indeed - that 'white stuff' you use on cars, FOUR wheels, and NOT on yer bike!
It cakes & glues & sticks like hell, a torture to get it off again - contrary to a thin smear of silicone inbetween the sliding parts, which will easily turn & come off when dismantling.
In the not-so-likely event you're talking about the white (and super rare & costly!) ceramic paste used on titanium exhausts then.... only on titanium systems, duh   

Yeah you are right it does stick rather well as i have found out , but it seals really well too   

Mauser wrote:

Zoro wrote:Sounds to me like it just needs a good run on the highway for an hr, stretch its legs..

That should clear things up.

Ahhhh   another speed freak lol, I don't mind the popping as long as its not all the time....the XJR is fantastic at popping lol.....must make the effort and pull the plug after a normal ride and post a picture for you guys....plugs best way to get an idea of mixture surely ?.

100kph/60mph, for an hr once a month.
Should keep the pipe clean, most likely stop some of the crap from building up on the back of the valves too.
Poor thing must feel like a caged animal potting around at 40 all the time, stretch her legs.