exhaust flame

[lee]

I removed the baffles from my AN Smoothness today and put in the washer / screw set up - I took it for a ride this afternoon and fine - I took it out again tonight and when I started it up there was a loud pop from the exhaust - when I got back and turned the bike off I noticed a small blue flame pop out the exhaust - any ideas??

Many thanks
Lee

 

[Gas Man]

Less backpressure and a little decel poping? Did you re-adjust the carb after you did this mod?

 

[lee]

I'm not sure there is less backpressure - I have the washer at 90 degrees to the pipe - I say I removed the "baffle" but this was simply a cone shaped piece of metal mesh near the end of the exhaust - not sure how much back pressure that would produce - I should try to get a picture of it on here - there is popping on decel but possibly less than there was before - looking at the plugs before and after, the mod seems to have leaned the mixture although I am running a 31 and a 78 - I haven't adjusted the carb as I have no spare jets - I do have some on order though for when I fit the triple X - it was also very cold yesterday
Thanks Gas Man - any further thoughts armed with the above info?

 

[mudslinger]

Give the washer's a little turn.

 

[lee]

Give the washer's a little turn.

but to do what? If I don't know what the symptoms are telling me how can I adjust to get things right? The bike seems to be running fine although as i say may now be a bit on the lean side whereas before the plugs looked as though I was maybe running a little rich

I know the washers going across increases torque (which I think it possibly did do) and running parallel increases top end power but I don't know what affect this has on the mixture

thanks Mud

 

[lee]

Thanks Sul

 

[slowrower]

Temperature range for Jets!

Any idea what the temp range is for say the 78? I went from a 76 to a 78 the other day and all is well. Of course it was 80F out, today high 60s ..

 

[Gas Man]

Sul is right on obviously and as normal...

 

[lee]

lee,

being cold the air is denser. could cause a leaner condition. if you plan to ride in cold weather then a jet change is in order.

i had the ness stacker long drag pipes. on the big inch motors they are not recommended by s&s. couldnt get them not to backfire. quieted them down some by tq cones and baffles. you might just be chasing your tail with those pipes. also check for an exhaust leak. the backfire is caused by air getting too high up the pipe. either from a leak or from coming back up the pipe on the compression stroke. this is why the 2-1 are so much better cause its constantly firing and no air can come up the pipe.

i put the stackers on my 88" fatboy and they were great.

sorry Sul I missed this part first time round - so you ran with baffles and cones at the same time? I got some Samson cones yesterday and was going to put them in with the washer set up but some people say don't do that (only use one or the other) and others say it won't hurt - Ray has heard the cones do nothing in big inch motors

 

[PROFLYER]

Mine shoots out a blue flame when I let off from the back pipe which is shorter. It's tuned perfectly, just happens with some pipes. The unburnt mixture that's left mixes with outside air and it ignites. Your old baffles prob kept just enough more back pressure to keep outside air from getting in the pipe exit, it looks sick at night I think, so I left it alone, plugs look great.

 

[slowrower]

there is no set range per jet. it matters how your motor "flows" on what jets you use. when i had my xxx G on i had a 70 main and a 29.5 int jet after a dyno showed the gain.

just figure that cold air is denser so you'll need more fuel to the mixture. if your riding a lot in 45 degree and down i'd re-jet.


of course all of this is IMO.

Thanks Sul, I am waiting until spring for dyno tuning.

 

[mudslinger]

I had that happen on my honda when I took out the baffles on the drags and used the washer setup.
Seemed that the washers were backing it up abit. It stopped when I turned my washers a little.
It also has to do with heat too.
Bike ran fine for years.
Sounded great too.
That's why I said to turn them to let the unburnt fumes out a little more.
That way they will not ignite.

But Sull is right you do need a rejet.

 

[lee]

Thanks Mud - I got a Triple X on its way so I'll leave it until that goes on - I'm gonna change the exhaust in the new year as well

 

[mudslinger]

I don't have all the answers Lee.
I just know what worked for me in real life.
I'm only speeking from my experiances.
And trying to help when I can.

That's Great your getting the new XXX!
Keep us posted on the install and actual tunning of the bike.:2thumbs:
Hope it is awsome for you!!!!