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The 2-Stroke Garage => Turning Wrenches => Topic started by: KANDY on July 30, 2025, 01:34:32 PM

Title: RD400 Jerking while deceleration
Post by: KANDY on July 30, 2025, 01:34:32 PM
Hi All,
1976 RD400, the bike is Jerking on Deceleration, goes away if I give a littlte throttle. Never observed in my RD350's. What is the cause and how to reduce/eliminate. Front Tyre 100/90/18. No issues Riding at any speed from 60 to 90MPH, The issue stats when down shift and decelerate.
Thanks
Title: Re: RD400 Jerking while deceleration
Post by: scully on July 30, 2025, 04:11:10 PM
closed throttle lean. close airscrew a bit or bigger pilot jet.
Title: Re: RD400 Jerking while deceleration
Post by: KANDY on July 31, 2025, 08:54:31 AM
Will try that, Thanks Skully.
Looks like not many have this issue here.
Title: Re: RD400 Jerking while deceleration
Post by: m in sc on July 31, 2025, 09:37:30 AM
check chain adjustment as well
Title: Re: RD400 Jerking while deceleration
Post by: 2steve on July 31, 2025, 10:12:22 AM
Quote from: KANDY on July 31, 2025, 08:54:31 AMWill try that, Thanks Skully.
Looks like not many have this issue here.

I certainly had that issue. Coasting slightly downhill in a neighborhood.
Can't ever remember if it's lean, or rich - LEAN :thumbs: 
Dave F mod in the carbs still does it on a 400, too.

Loose chain is also a very real thing.