Popping


15 replies to this topic
  • RX808

Posted June 12, 2006 - 03:49 AM

#1

I opened up my can on 05 wr450 and removed only the 1st baffle, left the spark arrestor in and have no tail pipe. It has really opened up the bike.

Now I went for a ride yesterday and the bike runs great but when the bike really started to warm upit started to pop on decel and wouldnt idle so i upped the idle and then the revs started hanging . The bike also became harder to start and when the bike was hot the hotstart still wasnt needed. I could also pull the hotstart in at idle and the revs wouldnt rise. I admit I wound up the idle abit to keep it from stalling but today I wound it back down.

Ive already got a 48 pilot in so I think a 50 will be over kill, needle is a red #4,
and bike runs great wide open so main doesnt have to be changed. I had the fuel screw set at 2 out and wound it to 2 1/2 and it didnt really change. The bike runs great all round bar the popping and hanging

Ive only got this week to sort it out coz theres a race on sunday, and i dont really have any ride time through the week> I havent played yet but I am thinking of richening the needle 1 clip, but apart from that this thing got me a bit stoked coz I think the jetting is rich enough, any thoughts??

I posted this in the exhaust mod thread yesterday but moved it to a new one today. What I did today was wash the bike and let it warm for a bit and took it for a ride round the block. Now there ws no popping and when I pul the hot start the idle rises which all seems fine, but the bike was not really warm like when you go for a good ride.????

  • Yamahondaha

Posted June 12, 2006 - 08:07 AM

#2

I opened up my can on 05 wr450 and removed only the 1st baffle, left the spark arrestor in and have no tail pipe. It has really opened up the bike.

Now I went for a ride yesterday and the bike runs great but when the bike really started to warm upit started to pop on decel and wouldnt idle so i upped the idle and then the revs started hanging . The bike also became harder to start and when the bike was hot the hotstart still wasnt needed. I could also pull the hotstart in at idle and the revs wouldnt rise. I admit I wound up the idle abit to keep it from stalling but today I wound it back down.

Ive already got a 48 pilot in so I think a 50 will be over kill, needle is a red #4,
and bike runs great wide open so main doesnt have to be changed. I had the fuel screw set at 2 out and wound it to 2 1/2 and it didnt really change. The bike runs great all round bar the popping and hanging

Ive only got this week to sort it out coz theres a race on sunday, and i dont really have any ride time through the week> I havent played yet but I am thinking of richening the needle 1 clip, but apart from that this thing got me a bit stoked coz I think the jetting is rich enough, any thoughts??

I posted this in the exhaust mod thread yesterday but moved it to a new one today. What I did today was wash the bike and let it warm for a bit and took it for a ride round the block. Now there ws no popping and when I pul the hot start the idle rises which all seems fine, but the bike was not really warm like when you go for a good ride.????

I thought my jetting was good till I installed an extended fuel screw. If you adjust the fuel screw past 2.5 turns you can probably use a bigger pilot jet and turn the screw in.

Since the carb was out I thought to raise the main needle clip by one position. Now it runs better and cooler so I might raise it one more at a time till it shows signs of too much fuel then back it up one position.

I have a tachometer on my Husky and it helps to dial in the fuel screw position. I am going to get a portable tach that connects to the plug wire for adjusting the fuel screw on the Yamaha. I would highly recommend using a tach to adjust the fuel screw position since it is much more accurate than your ear. On the Husky I tunned it by ear then turned the screw till I had the highest RPM. It sounded the same but the screw ended up 1/2 turn out from my hearing only adjustment.

  • Matty05

Posted June 12, 2006 - 02:22 PM

#3

Popping and hanging definately lean, as you know.

Get an adjustable fuel screw as mentioned before, they are seriously great!

If you need a 50 pilot, you need a 50 pilot.

Try going to #5 clip since it is getting cold here now. This might make a bit of difference to the hanging.

  • Dodjy

Posted June 12, 2006 - 05:14 PM

#4

As the others said, definitely lean. The hanging idle will be because you have adjusted the throttle position off the idle circuit (pilot) and are now using the needle to control the idle mixture. You need to back off the idle speed screw and work out why it is lean. At sea level a 48 should be fine so I'd be looking for a leak between the carby and cylinder, blocked pilot jet, missing o-ring in the fuel screw. Have you had the fuel screw out before? Is it the standard one or an aftermarket one?

  • Longtimeyamahaguy

Posted June 12, 2006 - 06:52 PM

#5

Make sure you put the plate on the flat slide on the slide correctly................

  • RX808

Posted June 13, 2006 - 03:02 AM

#6

what up Matty, I knew you would reply, haha.

Yeah guys the bike runs great.It only did this last weekend when I smashed the baffle out. I have an adjustable fuel screw. Ive turned it out ot 2.5 with a 48 pilot, buit theres no way I should need a 50.

It was running spot on when it wasnt so hot so if it was running lean should it have been running worse and got better as the bike heats up???

Like i said I washed the bike last night and took it for a ride around the block and everything is sweet, but i reckon when i take it out next as it gets hotter Ive got a feeling its gonna happen again. Ill see.

Ive had the carby out and raised the pilot but that was a couple of weeks ago no chance Ive got the slide wrong way around. Maybe might be a bit of dirt some where or leak building?

  • RX808

Posted June 13, 2006 - 03:05 AM

#7

Havent had the fuel screw out for ages since i put it in so the oring has to still be there, I might go to #5 as you suggest Matty.

  • Matty05

Posted June 13, 2006 - 05:34 AM

#8

Try that and keep on going out on the fuel screw. You do know how to set the fuel screw correctly, you know, find max rpm at raised idle..........

A lot of problems can be traced back to a dirty carby, I would take it off and blow out all the passages.

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  • Yamaster

Posted June 13, 2006 - 08:27 AM

#9

A hanging idle sounds like an air leak to me, plus I live at 2500 elevation and I use a 50 pilot jet because thats just what it needed. My 05 is stock except for the free mods and a boysen cover.

  • RX808

Posted June 14, 2006 - 05:33 AM

#10

Cheers guys for all the feedback.

After going over the carby, I found the hot start nut was a turn or so loose. Could this have any affect?

  • Yamaster

Posted June 14, 2006 - 08:19 AM

#11

Yes. The hot start is just an air passage that leans out the air/fuel mixture to start a bike easier when warm or flooded. With that nut loose it opened the direct air passage up and created a vacuum leak.

  • Dodjy

Posted June 14, 2006 - 04:28 PM

#12

Cheers guys for all the feedback.

After going over the carby, I found the hot start nut was a turn or so loose. Could this have any affect?

Sure does, I'd say that was your problem. The loose nut would be pulling the hot start on, leaning things out at idle and when you back off. You gotta watch those plastic nuts, I've hit mine a few times and pulled the cable up.

  • RX808

Posted June 15, 2006 - 12:55 AM

#13

Yeah i havent had a ride yet but id imagine thats solved half of it, might still go to #5 on the needle though see what happens. Ive got an aluminium hot start nut, i overtightned the plastic one the first time back on. Just want the bike running superb its my first race on sunday and ive chose to go in ythe ironman class on a 4 hour enduro.

Do you think smashing out the second baffle will make a noticable difference power wise over knocking just the first one out.

Once again cheers for the help .

  • Matty05

Posted June 15, 2006 - 02:42 AM

#14

Do you think smashing out the second baffle will make a noticable difference power wise over knocking just the first one out.

You would have to think so.....
Go for it!

  • Yamahondaha

Posted June 15, 2006 - 09:33 AM

#15

A hanging idle sounds like an air leak to me, plus I live at 2500 elevation and I use a 50 pilot jet because thats just what it needed. My 05 is stock except for the free mods and a boysen cover.

I check for air leaks by spraying a little WD40 or cleaner around the carb(y), if it has an air leak it will stall the motor. I just spray a small burst on all possible connections and wait a second after each spray to see if the idle changes.

  • Dodjy

Posted June 15, 2006 - 05:02 PM

#16

Do you think smashing out the second baffle will make a noticable difference power wise over knocking just the first one out.

Once again cheers for the help .[/QUOTE]

I'd probably leave the second baffle in for this race, I doubt that the stock muffler, without both internal baffles, would pass the sound test. Plus if the bike was running well mid and full throttle before, leave it so you don't risk stuffing it up for the race.




 
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