Revs not dropping

[widget]

Got a mate ...oh ok, someone I have met.......who has a Kettle that has had lots of money spent on it. It was rebuilt as it had this fault that could not be cured.....unfortunately it sill has the same fault......

After a run,(bike goes really well) the bike will not settle to tickover..

So... it has rebuilt crank, carbs, new lectric ignition, new sris valves , a different set of carbs has been tried, exhausts are clean, bikes charging well (lucky git)...new plugs....in fact there isn't much that has not been replaced...

Of course, the crank may be at fault, but would be unlucky for two cranks to have the same problem..though not out of the realms of possibilty. or possibly a crank case crack or fault....or a badly fitted crank that has pinched a seal....

We would like try absolutely anything to fix this bike as it is the chaps pride and joy and is a lovely bike.

Any thoughts or suggestions gratefully received..

[teazer]

Most often, revs not falling are caused by an air leak in the inlet system. That should be the first thing to check.

But it is also possible that the carbs need adjusting. L models on have push-pull cables and if incorrectly adjusted, the butterflies can remain partially open. There are adjusters on both ends of both cables to take care of and it's easy to get just the right amount of free play but have the throttles partly open.

On J/K models it is easy to check for free play and to ensure that the slides close fully.

After checking all the above, if you still have a problem, conduct both compression test and leak down test to see if you have a leaking seal. Early models used a steel plate to retain one of the oil seals. Later models used a different seal that is harder to displace and a rebuilt crank should have that upgrade. If the crank was rebuilt with the older style seal, the crank builder needs to be called out.

[widget]

Thanks for the reply...Air getting somewhere it shouldn't is my thoughts. Have checked cables, carbs snap shut quite well. Have tried pushing them shut just to make sure, and the other set of carbs were ok, but still get the same problem. I didn't see the crank before it went in so can't say what was done. He doesn't want to pull the motor apart until we have exhausted all other possibilities......It has new carb rubbers, new air filter....

[martyducati]

With the motor running spray easystart(other products are available )around the induction side of the engine and see if the revs rise/change,if there's a change try and isolate the problem area (separate the carbs with cardboard ect)IF there's a leak it will suck any gas in and cause the revs to rise hopefully finding your problem

[widget]

Thanks, will pass that on and get him to try it..

[PaulD738]

Carb cleaner works well too

[yeadon_m]

If its the later Kettle, has he tried opening up the fuel screws at the front of the carbs? you should be able to enrichen the idle to the point that it stalls. Try 3/4 turn out from gently seated (1/4 turn if its an L model) and then progressively more.
Good luck!
Mike

[widget]

Tis an A....all suggestions passed on..cheers..

[widget]

tried the easy start,,,,no pick up of revs...

[Waterbuffalo]

When you say not settle to tickover, what rev range are you referring to.