Hi everyone,
Hope you are all having a decent summer.
My 76 completely stock rd runs fine but something I have always noticed is that the left exhaust pulse is a strong POP POP POP without skipping a beat while the right side seems to be 2 little pulse per the left's, one.
I thought it was the exhaust baffle because i ordered a new one from the UK but recently I took them out and they look identical so I swapped them but the exhaust pulses didnt switch sides.
I checked timing with the timing light today and neither side has moved. Ive messed with idle screw and air jets on one side and not the other and cant get the pulses to be the same. I also tested for air leaks again and there are none.
I'm going to swap the carbs next to see if the issue switches sides as well....
Anyone ever seen anything like this?
Are your carbs synced
Hey Rodneya,
What I do to get carbs the same is when i have them out I push the slides down with my finger and put the idle screws in until they just touch then I paint a white line on the heads so they always get adjusted exactly the same.
I also took those two screws out to make sure the little dots in the slides are equal by adjusting the cables when they are full throttle.
That's about all I do. The bike certainly seems to run fine and pulls well... its just this weird idle exhaust pulse thing... and I'm not sure which side is best to have... the strong POW POW POW or the other side's double and smaller pulses.
I'm going to swap carbs today and see if the issue swaps sides.
Swap the carbs report back.
Are the air mixture screws the same for both sides?
what does it do if you raise the idle speed on the right side only?
How are the cylinder head temps are they close in temperature?
You state that it runs fine in your first post. I wouldn't do anything that might jeopardize that to just even the pulses at idle.
Quote from: pidjones on September 28, 2020, 07:18:12 AM
You state that it runs fine in your first post. I wouldn't do anything that might jeopardize that to just even the pulses at idle.
Agreed. This is just an idle sync issue most likely.
Don't worry about exact turns on the idle screws per each side with markings, do what the bike wants.
If you slowly turn one idle screw in on one side while going out on the other, you'll see a difference.
It won't take much adjustment at all.
Throttle cable free play too. :twocents:
Some common things that can cause this symptom:
1. Pilot circuit partially clogged
2. Carbs not synced properly
3. Battery weak (or beginning to fail)
All of these can cause a slight misfire :twocents:
Quote from: SoCal250 on September 28, 2020, 06:55:44 PM
Some common things that can cause this symptom:
1. Pilot circuit partially clogged
2. Carbs not synced properly
3. Battery weak (or beginning to fail)
All of these can cause a slight misfire :twocents:
+1 If the carbs have not been cleaned recently I would pull them and clean. You will probably find a pilot that is starting to clog.
Thanks for ideas everyone. I never got around to swapping carbs yet. Ya, the bike runs good... well as far as I know... first RD I have ever owned, I was just worried it was a symptom of something else... like reeds not sealing or carb not set up correctly... something wrong with ignition etc etc. I've had the carbs apart twice to check to make sure all the jets were the same size and needles are at same clip and while I was in them I compressed air the jets and passages in both.
I'm also curious... why does one side have such strong individual pulses and the other has weaker more frequent pulses? I find that really weird... and which side is the correct one at idle?
Swapping carbs seems to be an easy thing to do so I'll try just to see if it switches sides. I'm hoping to get to it this weekend.