Runs on regular/87 Octane fuel only.
Would run to 9000RPM easily, not too happy about being pushed past that.
Symptoms
Popping on deceleration...this came on rather quickly.
Increase in fuel consumption by about 25%
Bike used to start with only a sharp push of the start button, hot or cold.
It began taking a bit longer when cold. Much longer at or below freezing.
Treatment
Air cleaner checked.....OK, not due for cleaning, but replaced the stock cleaner with a new K & N free flow.
NGK B8ES Plugs all checked out medium to dark tan, electrodes OK, with little wear, but plug bodies are getting corroded on outside.
Replace with new NGK B8ES
Install new fuel filter.
New Symptoms
Bike starts OK, idles fine, pulls fairly well at low RPM, but will not tolerate open throttle.
Bogs badly above 3/4 throttle opening until over 5000RPM.
Max available RPM 8500.
Pull carbs and open them up.
Two have tiny bits in the pilot jet. Blow clean, check all through. All working fine.
Reassemble. Remount carbs on bike.
Check all fittings. All OK.
Bike starts well, still bogs in any gear when throttle is opened sharply, but will rev if allowed to run up slowly. On medium throttle, it pulls OK under 5000, but power curve is not as good as it was before.
At 5500/6000 at full throttle it changes personality....from there it revs very strongly to 10500 in 2,3, and I did not take it above 9000 in 4. Never saw 10500 before, and it never ran this well above 6000.
Gas mileage is still down, but not as bad as it was.
15 litres (4 US Gal) for 205km /125 miles.
Pull plugs.
All are the same.
Centre electrode is clean white, looks like brand new and unused, has acquired no particles or any marking. Farther down the insulator ...roughly even with the rim of the body... a soft black covering begins. (Brushes away easily with wire brush)
Body of plug, outer edge/rim has the same soft black covering. Side electrode is clean at the tip, but also has a soft black coat near the base/body.
Found a small hole in left side exhaust pipe (about 1/4 inch), just ahead of the muffler.
Nothing done about that yet.
There is obviously no fuel flow problem, as it pulls so very strongly at high RPM.
Fluffy deposits on the plugs suggest a rich mixture, but the white tip suggests too hot a plug, or timing is off, probably advanced too much, which could also contribute to the improvement at higher RPM 's, but they could have benefitted from the improved air flow of the K & N filter.
The manual says nothing about adjusting electronic ignition timing. Could this be a rotor/pickup problem? Other than visual inspection,( which I have not yet done) what is the best way to check it?
Comment