Smoking badly from right hand pipe

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kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Smoking badly from right hand pipe

#1 Post by kampinguru » Tue Sep 19, 2017 10:20 am

I have had the motor completely rebuilt and new pistons and rings with a bore. I started the bike and it smokes a little bit from the left hand pipe as expected but the right hand side has the mosquitoes running for their lives. I am also having low RPM stumble when leaving in first gear and when idling. I recognize the carburetor but have not idea how to adjust it. Anyone have any suggestions? I had a mechanic at the Yamaha dealer supposedly get it running and tuned, but it runs like S#!t now. Once it hits about 5 grand, it takes off. Any assistance on where to start would be greatly appreciated. Bike is completely stock with the exception of 1 oversize on the pistons after the rebore. Thanks.

hondaror
Posts: 2828
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Smoking badly from right hand pipe

#2 Post by hondaror » Tue Sep 19, 2017 12:05 pm

There is a chance that the piston clearance on the right size is loose compared to the left. No work is ever perfect. If that's the case, you should warm up the bike before riding, always, when it's a cold start. The air screws should be lightly screwed in all the way and then backed out 1 1/2 turns. Then with the bike running turn them out a quarter turn to see if it idles better. If it's worse, go back to the 1 1/2 and then try in 1/4 turn. You need to find the sweet spot. The stumble on launch, give it more gas. Ride the bike hard. Your jetting is likely rich. I'd bet my left nut on that.
Is the bike stock? If it is, try taking the slides out and pulling the needles. Move the clip UP one notch. When you start it and rev it, the bike should respond quicker and feel crisper from 1/4-3/4 throttle. This is because you just leaned out your fuel mixture on the needle. If this is the case, and it runs good, you also need to drop the size on the main jets. Just make one adjustment at at time to both carbs, then test ride. Have fun. This is the hardest part of tuning. A ton of work. Hint: don't pull the carbs every time you have to go in, just rotate them so you can get at the bottom to make the changes.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

MK
Posts: 814
Joined: Sat Nov 26, 2005 11:44 am
Location: Wolfenbüttel, Germany
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Re: Smoking badly from right hand pipe

#3 Post by MK » Tue Sep 19, 2017 2:27 pm

Sometimes residual oil in the cases csuses a bit more smoke. Also a too cold combustion (i.e. too rich but also too lean fuel setting can cause this)
If the smoking does not cure on it's own, read the next lines ...

With rebuild you refer to solely a top end job and didn't check the crank?
Really excessive smoke usually is caused by a damaged right crank seal. And usually that's a result of a failed bearing.
If you had it apart you may damaged the seal whilst mounting it?
Bye
Martin

kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Re: Smoking badly from right hand pipe

#4 Post by kampinguru » Tue Sep 19, 2017 4:01 pm

Thank you for your replies. This was a full engine rebuild with a new crank and all new seals and gaskets as well as new pistons rings and a bore. The rebore was done by a reputable machine shop in the area. The rebuild was done by a Yamaha mechanic who is familiar with the bikes and worked on them before.
Sounds like I first need to take it out and run it like I stole it. Not sure if that is the best way to break the engine in but I will get it warmed up and take it for a squirt tonight. I hate carb work. But it is part of owning a smoker. I never had to touch them when I was racing. They were set and forgotten about and the bike ran great on the track.

AlexG
Posts: 35
Joined: Sun Jul 31, 2016 8:32 am

Re: Smoking badly from right hand pipe

#5 Post by AlexG » Tue Sep 19, 2017 6:19 pm

Can it be the crank seal from that side allowing oil from the gearbox to be sucked in?


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kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Re: Smoking badly from right hand pipe

#6 Post by kampinguru » Tue Sep 19, 2017 6:27 pm

It was a new seal when the engine was rebuilt so unless the tech tore it when he installed it, i dont suspect that. I am leaning towards Rory and his running rich theory. It was smoking badly from that pipe when i parked it 18 years ago so with the rebuild and still smoking, it is probably jetting. I used 185 mains which were in it from the factory when i rebuilt the carbs and left the needles in the stock position where they were when i took it apart.

hondaror
Posts: 2828
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Smoking badly from right hand pipe

#7 Post by hondaror » Tue Sep 19, 2017 10:51 pm

kampinguru wrote:It was a new seal when the engine was rebuilt so unless the tech tore it when he installed it, i dont suspect that. I am leaning towards Rory and his running rich theory. It was smoking badly from that pipe when i parked it 18 years ago so with the rebuild and still smoking, it is probably jetting. I used 185 mains which were in it from the factory when i rebuilt the carbs and left the needles in the stock position where they were when i took it apart.
Información is good. Is the bike an F1 or F2?
What pipes are you running?
If the pipes are stock and you were rich back then, they will be plugged up with oil. A new set of chambers will remedy that quickly. It helped mine. You can always try to unplug them. High heat burns off the oil. I'm going to soak mine in a solvent to try and clean them out. I'd like to use them on one of my stock builds.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Re: Smoking badly from right hand pipe

#8 Post by kampinguru » Wed Sep 20, 2017 7:27 am

The bike is a 1989 F2 with stock pipes. I took it for a ride last night and the smoking got less once it was good and hot but it was unrideable below 5K. I had a hard time keeping it running when i slowed down for a light. Almost stalled it a couple times pulling away from a light then it would take off all of a sudden and almost wheelie. When you say move the clip up, am i dropping the needle or are you saying to move it closer to the pointed end and this raising the needle? There is the Air screws and the Idle adjust screws. You say Air screws to adjust when the bike is running but did you mean idle adjust screws? Sorry but I have no idea on carbs. I always left that to experts. Thanks again

gpaddict
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Joined: Mon Nov 06, 2006 8:35 pm
Location: WISCONSIN

Re: Smoking badly from right hand pipe

#9 Post by gpaddict » Wed Sep 20, 2017 9:36 am

Sounds like its dropping a cylinder below a certain rpm. Check the carb slides for equal movement.
tuned to Paris Hilton specs............rich and retarded!

kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Re: Smoking badly from right hand pipe

#10 Post by kampinguru » Wed Sep 20, 2017 9:52 am

I will check those tonight. I will need to pull the slides to change the needle setting anyway. Thank you.

hondaror
Posts: 2828
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Smoking badly from right hand pipe

#11 Post by hondaror » Wed Sep 20, 2017 11:24 am

Yes, the clip up one notch. It drops the needl down to lean it out. You'll know if it was the right move.

The flat screws are the air screws, both on the same side of the carbs. You'll need a long skinny slot screw driver for those.

I think your pipes are bungged up.

Carb sync should be done with a unisyn, based on vacuum.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Re: Smoking badly from right hand pipe

#12 Post by kampinguru » Wed Sep 20, 2017 12:05 pm

Are they cleanable? How do I know if ones I buy are plugged too?

hondaror
Posts: 2828
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Smoking badly from right hand pipe

#13 Post by hondaror » Wed Sep 20, 2017 5:02 pm

Buy chambers, there's nothing to plug but the silencer.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

hondaror
Posts: 2828
Joined: Mon Mar 03, 2014 8:44 pm
Location: Alberta, Canada

Re: Smoking badly from right hand pipe

#14 Post by hondaror » Wed Sep 20, 2017 5:03 pm

My Toomey's and K&N pods were good for an additional 14 wheel hp.
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine

kampinguru
Posts: 84
Joined: Mon Dec 07, 2015 10:15 am
Location: Milton, Ontario

Re: Smoking badly from right hand pipe

#15 Post by kampinguru » Thu Sep 21, 2017 8:15 am

Well i tried the airscrew last night and that did nothing. Maybe a bit better out a 1/4 than in. I dropped the needle next and when i started the bike, it idled at 6 grand. Blipped the throttle and it settled down for a second then several more blips and it raced rhe engine. Shutting off the key didnt do anything. I blipped the throttles again and it idled down and shut off. Smoke seemed less and was even from both pipes. Ran out of time but i think i am on the right track. I think i will try the air screws again as my next step. Wo dering if the racing was caused by a sticky carb slide. May have to get the carbs cleaned ultrasonically. Might put a new 180 main jet in while i have them out to clean. Am i off base anywhere? I appreciate your help. Let me know if i am not providing enough info.

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