US spec. butterfly

[Duinhoven_Hans@emc.com]

Dear list,

My HS4's still have the USA spec butterflies with a spring loaded valve.
Could this be one of the causes the engine does not run well still?

It vibrates around 2000 RPM
When cold sometimes there is a backfire in the carbs
Even when running higher revs in 4th gear I sometimes hear a backfire.

TIA


Regards,

Hans

71 BGT

///
///  mgs@autox.team.net mailing list
///  (If they are dupes, this trailer may also catch them.)