Problems with surging

[Varadero]

I have an 88 vmax. It has a problem running evenly and in 5th gear there are noticeable surges every few seconds. There has been extensive work done on the engine however no one here seems to know why this is happening . Can anyone help?
Thomas

 

[MaxMidnight]

It would help if you could say what the 'extensive' work consisted of.

 

[Varadero]

The engines carbs have been rebuilt with new vacuum rubber and points, the fuel lines have been replaced. This may not be extensive for some but it is for me.

 

[Varadero]

Can't remember what else but there is more.

 

[MaxMidnight]

Have you checked the basics, I.e. carb. synchronisation, fuel and air filter have been changed or cleaned in .Ivinghoe memory?

 

[tvmax]

Fresh set of plugs. I would clean the carbs again. Float not right or a clog in a passage.

 

[Fire-medic]

Suspecting a partially-plugged fuel filter, or possibly diaphragm is out of place in the fuel pump, both easy fixes, involving labor more-than $$$ parts, tools, and intimate knowledge of the bike.

http://vmoa.net/VMX12-Service-Manual01.pdf

 

[one2dmax]

If you can give it just a slight bit more throttle to even out then it might just need a shim or clip adjustment on the needle. OR, we've had that issue in the past with a bad main slide rubber.

 

[Varadero]

Have you checked the basics, I.e. carb. synchronisation, fuel and air filter have been changed or cleaned in .Ivinghoe memory?

Thanks. Carb sync hasn't been checked. I'll look into that. Let you know if that works.

 

[Maxnewby]

I hate when this happens post for help and after not even courteous enough to say if it did help.

 

[Fire-medic]

Yes that would be good to hear/see.