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The 2-Stroke Garage => Turning Wrenches => Topic started by: patastinky on December 07, 2020, 01:14:38 PM

Title: Bike started, but only one side smoking
Post by: patastinky on December 07, 2020, 01:14:38 PM
So I have spark at the plug on the left side. However I'm thinking maybe fuel is the problem so I'll need to take apart the carb I guess and see if there is any fuel in the bowl?

Also at first it felt like it was going to run away from me so I had to cut the power by turning the key to the off position.

Any tips on trouble shooting this further?

Here's a video

https://youtu.be/19Sstl-_fFQ

Covering the exhaust with hand
https://youtu.be/72ZLv4qH6zY

Title: Re: Bike started, but only one side smoking
Post by: SoCal250 on December 07, 2020, 01:35:46 PM
You have multiple issues from the sound of it -- high idle on the right and no fire on the left.
Is fuel flowing from the petcock to the left carb?
Check float levels and valves. (float level is ~15mm for a RD350)
Make sure the jets are completely clean, especially pilots. Have these carbs been cleaned recently?
Do the the slides move freely through their range and are they seated all the way down at idle?
Are the idle screws set correctly?
Is the crossover tube between the carbs connected?

Is this with the bad battery you recently posted about? A weak/faulty battery can cause it to run on one cylinder.
Title: Re: Bike started, but only one side smoking
Post by: patastinky on December 07, 2020, 01:57:22 PM
Quote from: SoCal250 on December 07, 2020, 01:35:46 PM
You have multiple issues from the sound of it -- high idle on the right and no fire on the left.
Is fuel flowing from the petcock to the left carb?
Check float levels and valves. (float level is ~15mm for a RD350)
Make sure the jets are completely clean, especially pilots. Have these carbs been cleaned recently?
Do the the slides move freely through their range and are they seated all the way down at idle?
Are the idle screws set correctly?
Is the crossover tube between the carbs connected?

Is this with the bad battery you recently posted about? A weak/faulty battery can cause it to run on one cylinder.

Hey Socal- thanks for your help with this. I've answered your questions below.
Title: Re: Bike started, but only one side smoking
Post by: rodneya on December 07, 2020, 03:47:42 PM
What does the plug on the non running side look like?
have you done a leak down test?
Title: Re: Bike started, but only one side smoking
Post by: patastinky on December 07, 2020, 04:10:34 PM
Quote from: rodneya on December 07, 2020, 03:47:42 PM
What does the plug on the non running side look like?
have you done a leak down test?

Looks dry. They leak down do you mean compression test? The motor was rebuilt. Installed installed new piston and rings. Plus cylinder bore and crank rebuild. I can do a compression test tonight
Title: Re: Bike started, but only one side smoking
Post by: Arrow on December 07, 2020, 04:19:58 PM
A leak down test is not a compression test. It checks for any leaks in the crankcase or any where in the 2 stroke pumping area, intakes etc, etc.

Sent from my SM-G973F using Tapatalk

Title: Re: Bike started, but only one side smoking
Post by: rodneya on December 07, 2020, 04:21:03 PM
Quote from: patastinky on December 07, 2020, 04:10:34 PM
Quote from: rodneya on December 07, 2020, 03:47:42 PM
What does the plug on the non running side look like?
have you done a leak down test?

Looks dry. They leak down do you mean compression test? The motor was rebuilt. Installed installed new piston and rings. Plus cylinder bore and crank rebuild. I can do a compression test tonight

Nope, leak down you plug the intakes and exhaust ports and pressurize to 6 psi for 6 to 10 mins to check for air leaks.
Title: Re: Bike started, but only one side smoking
Post by: SoCal250 on December 07, 2020, 06:34:50 PM
I agree, needs a leakdown performed. I think there are several things going on, air leak is possibly one of them.
Here's some info to help out with the test: THE TECH LIBRARY »ENGINE (http://www.2strokeworld.net/forum/index.php?topic=55.msg233#msg233)
Title: Re: Bike started, but only one side smoking
Post by: patastinky on December 07, 2020, 07:38:34 PM
Quote from: SoCal250 on December 07, 2020, 06:34:50 PM
I agree, needs a leakdown performed. I think there are several things going on, air leak is possibly one of them.
Here's some info to help out with the test: THE TECH LIBRARY »ENGINE (http://www.2strokeworld.net/forum/index.php?topic=55.msg233#msg233)

Cool. I downloaded the PDF and will build the tool to leak down test

Otherwise, is there anything else I can check too?
Title: Re: Bike started, but only one side smoking
Post by: Djg8493 on December 08, 2020, 12:20:57 PM
As an FYI Dorman makes the expansion plugs that fit the exhaust ports, they are part number 570-008 1 3/8 is the size. 
Title: Re: Bike started, but only one side smoking
Post by: patastinky on December 08, 2020, 12:29:51 PM
Quote from: Djg8493 on December 08, 2020, 12:20:57 PM
As an FYI Dorman makes the expansion plugs that fit the exhaust ports, they are part number 570-008 1 3/8 is the size.

thank you
Title: Re: Bike started, but only one side smoking
Post by: AAAltered on December 09, 2020, 01:19:46 PM
Take Joes advice and check your slides.  Backward slides are a simple mistake that can be part of your running problem.  I've seen it.  "Cutouts face rear"
Title: Re: Bike started, but only one side smoking
Post by: Nkreig on December 09, 2020, 03:58:30 PM
Just like Ed and Joe mentioned.  Check the slides are in properly with cutout facing the air filter side.  Also, check your cables where they seat into the top of the carb.  I've had them hang up on the top of the adjuster and hold the slide up a little causing the same issue you're having.  Good luck
Title: Re: Bike started, but only one side smoking
Post by: Greaser Greg on December 09, 2020, 07:32:53 PM
Quote from: Djg8493 on December 08, 2020, 12:20:57 PM
As an FYI Dorman makes the expansion plugs that fit the exhaust ports, they are part number 570-008 1 3/8 is the size.
I made rubber gaskets out of inner tube that when sandwiched between header, or an exhaust bracket and cylinder seal it as well.   :twocents:
Title: Re: Bike started, but only one side smoking
Post by: paul1478 on December 10, 2020, 08:07:35 AM
Quote from: AAAltered on December 09, 2020, 01:19:46 PM
Take Joes advice and check your slides.  Backward slides are a simple mistake that can be part of your running problem.  I've seen it.  "Cutouts face rear"

WAW back when, around 79 when I rebuilt my 350, I put it all back together, ran like shit. I could not figure it out. I called the guys who bored it and asked if it could need a bigger jet due to the new size. He said, you have your slides in the wrong carbs. I thought no, not posable.
Yep.
Title: Re: Bike started, but only one side smoking
Post by: NYSingh on December 15, 2020, 04:57:06 PM
In addition to what everyone else said: