[snowmad]

Ah you let him loose on your carbs then. yes it sounds like his work!
Take photos of the choke plunger, side view and end on so i can see the condition and also the carb body seating.

 

[chronyx]

@snowmad

I just found this thread via the search and have a quick question if you don't mind. I think I have identified a small intake leak on my RD07A, spraying brake cleaner around the rubber carb to inlet manifold rubbers. However it also seems like the carbs themselves are drawing in air, if I spray around the centre of the carb assembly I also get a rise in RPM, although it is hard to be precise with the spray.

Does this sound possible/likely to you? If so would it just be some sort of O ring that has perished? Or would the carbs need a specialist rebuild?

Idle speed doesn't seem to hang, although there is some backfiring just revving in neutral.

Thanks for any help!

 

[chronyx]

I just took the carbs off again and found some play in the throttle plate mechanism. I wonder if air could be drawn in here? I have videoed it as best as I could with one hand!

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[snowmad]

Well as you say you have found a small air leak in the carb rubbers, this would draw in the brake cleaner as some of it will quickly turn to gas even if you are just spraying around the carbs but also the rubbers to the airbox. Either of these would lead to a rise in RPM. Take it step by step and after fitting new rubbers, try the brake cleaner test again. If it still rises i would suspect its entering via a leak on the airbox rubbers side. If your idle is stable (when warm) it is unlikely to be leaking serious amounts (or any ) air in where it shouldnt. The backfiring on throttle shutting from raised RPM will be air being drawn in via the air leaks you have found after the throttle butterfly, in the rubbers, so fitting new ones should eliminate that. As for play in the throttle plate shaft, some wear is likely to be there, but as long as when you blip the engine it always settles to a steady idle within a few seconds, not maintaining an elevated idle or erratic idle then there is nothing to worry about.
Sorry cant see your video as i dont have Veed. Post it as something standard like MPEG4, AVI etc. If you still have the carbs off it would be a good idea to go through them and replace whatever gaskets and seals you can. Probably a good idea to replace the float needle valve as yours are bound to be old and who knows how long they will be available. Either way check the float height (refer to manual) as many people overlook this and then have fuel mixture issues on all sorts of petrol engines! Also make sure the carb airflows are balanced and idle mixture screws adjusted and it should tick over like a Swiss watch (like mine). I extended my idle screws to make them easier to adjust by hand in the middle of the hot V twin, as shown in a previous post.
Happy twiddling !

 

[chronyx]

Well as you say you have found a small air leak in the carb rubbers, this would draw in the brake cleaner as some of it will quickly turn to gas even if you are just spraying around the carbs but also the rubbers to the airbox. Either of these would lead to a rise in RPM. Take it step by step and after fitting new rubbers, try the brake cleaner test again. If it still rises i would suspect its entering via a leak on the airbox rubbers side. If your idle is stable (when warm) it is unlikely to be leaking serious amounts (or any ) air in where it shouldnt. The backfiring on throttle shutting from raised RPM will be air being drawn in via the air leaks you have found after the throttle butterfly, in the rubbers, so fitting new ones should eliminate that. As for play in the throttle plate shaft, some wear is likely to be there, but as long as when you blip the engine it always settles to a steady idle within a few seconds, not maintaining an elevated idle or erratic idle then there is nothing to worry about.
Sorry cant see your video as i dont have Veed. Post it as something standard like MPEG4, AVI etc. If you still have the carbs off it would be a good idea to go through them and replace whatever gaskets and seals you can. Probably a good idea to replace the float needle valve as yours are bound to be old and who knows how long they will be available. Either way check the float height (refer to manual) as many people overlook this and then have fuel mixture issues on all sorts of petrol engines! Also make sure the carb airflows are balanced and idle mixture screws adjusted and it should tick over like a Swiss watch (like mine). I extended my idle screws to make them easier to adjust by hand in the middle of the hot V twin, as shown in a previous post.
Happy twiddling !

Thank you, i am on phone at the moment since posting as PC crapped out so excuse short reply. Have ordered new rubbers. No air box fitted at time of testing. But did settle down to a lovely smooth tickover when well warmed up. You should just be able to click on the link and close any pop ups asking to log in! If not i will see what else i can do, it was quite a large file.

 

[snowmad]

Well if tick over was smooth when hot and you have yet to fit the new carb to head rubbers then you dont have any carb issues and even the air leak you detected must be small. If you had no airbox on when you were spraying brake cleaner over carbs then some would have been entering via the intake rubbers, hence the rise in rpm. Still cant view the file, but no matter.