I've had my 3 1/2 Strada for many a year and upped it to 378 more years ago than I care to remember (378 barrels and pistons). I didn't change the carb jetting and it ran OK - not earth shattering but different in a good way.
Should I change the jetting and if so what to? Any suggestions gratefully received!
John.
Jetting for 378 Engine
Re: Jetting for 378 Engine
If the jetting doesn't have any obvious faults, then making it 'better' is going to be difficult without diagnostic equipment.
The old school approach is to use 'plug cuts' but for that you need a long straight level road with little traffic.
You run along with the throttle held constant at the point you are interested in before cutting the ignition and pulling in the clutch.
The plug colour would then be examined to determine the mixture, but modern fuel can lead to the plug looking just black over quite a wide range.
A rolling road is one approach, but ideally an 'absorbtion' type where the engine can be held at a constant load or constant rpm and not the more common inertia type. The results will depend a lot on the skill and experience of the operator and the costs can be quite high. One limitation is the lack of airflow past the bike, not so much for cooling, but for its effects on carburation. On the road the air entering the carbs may be cool and turbulent, whilst on the dyno it may be hot and relatively still.
You can now buy portable exhaust gas analysers that can be used whilst the bike is being ridden. I believe NLM can offer this service and it's probably the most cost effective solution although you're not going to get any power figures to use as 'bragging rights'.
The old school approach is to use 'plug cuts' but for that you need a long straight level road with little traffic.
You run along with the throttle held constant at the point you are interested in before cutting the ignition and pulling in the clutch.
The plug colour would then be examined to determine the mixture, but modern fuel can lead to the plug looking just black over quite a wide range.
A rolling road is one approach, but ideally an 'absorbtion' type where the engine can be held at a constant load or constant rpm and not the more common inertia type. The results will depend a lot on the skill and experience of the operator and the costs can be quite high. One limitation is the lack of airflow past the bike, not so much for cooling, but for its effects on carburation. On the road the air entering the carbs may be cool and turbulent, whilst on the dyno it may be hot and relatively still.
You can now buy portable exhaust gas analysers that can be used whilst the bike is being ridden. I believe NLM can offer this service and it's probably the most cost effective solution although you're not going to get any power figures to use as 'bragging rights'.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru