As discussed before my RE plugs are very sooty.
120/38 jets VD83 carbs venting to atmosphere.
Float heights all good, choke circuits all good and operating in sync. Valve guides do not appear oily and bike uses little oil. Idle mixture adjustments make no difference. Bike runs throughout rev range with no problems.
Any suggestions on what I might try next?
Do you know if the needles have circlip type or the normal “flat-top” type.?? Do they have any shims underneath their heads…??
If the idle mixture screws make no difference, the fuel must be getting in through somewhere else. If I screw my mixture screws in too far, the engine will stall. 2 to 2-1/2 turns out is the stock setting.
Smithy.
Needles are held in by a nylon lock piece - no circlip. No shims on needles. Idle mixture adjustments do change engine revs but leaning mixture does not stop the sooty plugs. Idle mixture set to get best idle.
Needles have a 1H5 stamped on them.
Hmmm. I have 140/40 main and pilot jets in mine and the plugs come out with a tan colour to them. I have a Factory-Pro jet kit with the needles on the “mid” circlip position…but I do have a set of stainless “cross-over” headers and high flow air filter fitted…
Pic below is looking from underneath rear towards front.
Smithy.
Thanks for the reply. I think I might have to accept the fact that the engine is burning some oil via the rings or valve guide seals and that this is the cause of the problem.
Is it using a silly amount of oil…?? Mine uses a very small amount, negligible though…and certainly not enough to worry about…
Smithy.
It does not use a lot of oil - never have to top up between oil changes but I do not do big kms between oil changes. Might take a long shot and drain some oil from the engine to see if having the oil level at a lower level helps.
In my experience, running the oil lower than mid point of the dip stick is not good…when the engine is running, much of the oil is up in the heads and rocker covers, takes a while for it to drain back…this leaves precious little for the bottom end and gearbox…oiling is poor at best on these engines to start with. I run an oil pressure guage on mine so I can keep an eye on things on the fly.
Smithy.