MOTOBRICK.COM
TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Jafet on October 21, 2024, 11:10:07 PM
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Greetings,
First of all, let me introduce myself—I'm Greg from NY. I came across this community while searching for a solution to my problem and was amazed by all the information and resources here. With that said, I’ve been having an issue with Cylinder 4 at idle, where it's not showing any readings on the Carbtuner (i tested it on another bike and works perfect). I did a quick check for leaks (not as thorough as I’d like since I was short on time last week), so I plan to revisit that. In the meantime, I’m looking for suggestions on what the problem might be. I’ve also ordered a throttle body rebuild kit, though I’m not sure if that will solve the issue. Either way, the rebuild is overdue since it’s still running on stock parts. Video attached below.
Thanks in advance for any help!
https://youtu.be/lTgZC9_LWL4?si=ErwXV1RpadDbnTLx (https://youtu.be/lTgZC9_LWL4?si=ErwXV1RpadDbnTLx)
(https://youtu.be/lTgZC9_LWL4?si=ErwXV1RpadDbnTLx)
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http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/tbleak/tbleak.htm
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Also try to switch the sparkplug cable from 2 to 4 see if the problem switches cyl.
Same goes for their sparkplug.
That will be a cheaper fix than boots or any air related leaks.
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I ment cyl 1 and 4*
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I did a quick check for leaks (not as thorough as I’d like since I was short on time last week),
A "quick check for leaks" needs some fleshing out to become a useful description.
What is the production year of your Brick?, How long have you owned it? How much have you ridden it? What is the mileage on the odometer? How well was the engine running before you undertook this test? Was the exhaust pipe for cylinder #4 cooler than those of the other cylinders after idle? Do you know when the last time the valve clearances were adjusted?
If there is spark at all plugs, before I did anything else I'd warm up the engine, shut it off, then do a compression test of each cylinder with the throttle wide open.
If compression were okay, I would connect the Carbtune, start the engine, let it idle, go to the air balance screw of the throttle body #4, note the position of the air balance screw of throttle body #4, open and close—not completely—the air balance screw during idle to see if that had an effect then return the screw to its original position. If no effect, I would start the engine, let it idle, take a propane or Mapp torch and train a narrow stream of unlit gas around each rubber bushing and manifold connected to the air box to each throttle body, and listen for a change in the idle. A change would indicate a leak.
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Also try to switch the sparkplug cable from 2 to 4 see if the problem switches cyl.
Same goes for their sparkplug.
That will be a cheaper fix than boots or any air related leaks.
I don't understand your last sentence. If the issue is a leaking TB boot then you need to repair it.
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I don't understand your last sentence. If the issue is a leaking TB boot then you need to repair it.
What I ment was, check if the issue is caused by the cheaper fixes first. Before you end up replacing part that you dont need and are expensive.
Those intake manifolds or "boot" are on the expensive side
It had nothing to do with not having to repair it.
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:twothumbsupp
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Thank you all, I just got the rebuild kit for the throttle body, took the bike apart and already saw 2 vacuum hoses that might need replacing, which i ordered them both. Ill be working on the TB tomorrow and most likely putting it all together over the weekend, ill follow up with results. Thank you!