Steamchick
Just got it firing!
Hi all... I'm new to this chat-line so forgive me for having "zero" background. - My assumptions are all probably off-target?
Also, I couldn't find a "Model specific" V50II sub-site...? - Any suggestions?
I have owned a V50II for 23 years... used small-time for commuting and local trips... but until 2018 the commuting etc. was mostly 3 miles town/dual carriage-way, then a 3 mile blast at up to legal speeds (honestly, your honour...). But traffic had been getting very thick so in the last few years I had been spending more and more time trying to keep the idle working usefully, and minimising "pops" on over-run.
So retirement came, and I'm down to a couple of hundred miles a year (local town work mostly) - and have finally reached a fairly usable tick-over!
But the bike has always had a huge flat-spot below 2500rpm... where opening the throttle too much ay low revs (1500rpm~2500rpm) it makes a hell of a lot of intake noise with very little increase of performance.
Now I worked in engine design on cars back in the late 1980s~90s. I've been around engines and bikes for over 50 years, but am always willing to learn - especially about carbs - as I have never had to do much real carb tuning. (mostly "stock bikes and a lot of use", rather than "a lot of tuning and rarely used").
During recent pandemic restrictions I spent a bit of time studying the mixtures I get - because the bike doesn't suit the congested city driving I do mostly... which seldom gets to the 30mph limit, and when it does the speed cameras are everywhere!!! So this riding is a common thing for me now, so instead of blasting around at 1/2 throttle and up I am tootling along at barely a crack of throttle. Something the Original designers (nor I) ever envisaged for this bike.
The idle - being set, working and stable, and showing a good burn with the optimate (glass spark=plug), just doesn't like the throttle being open slightly. The mixture goes exceedingly rich until about 1/4 throttle - which I understand is the slide cut-away ratio along with the pick-up orifice just up-stream of the slide.
The bike has VHB carbs.
From 1/4 throttle upwards everything is fine, and in tune. Carbs have been cleaned, (Ultrasonic and chemical) and I am now sure all passages are as "originally intended".
I suspect the rich mixture - just off idle before the slide opens 1/4 or more - is a "fuel boost" to prevent the engine dying when pulling away moderately (The new experience for me..). I had learned (20-odd years ago) to feather the throttle to get past the flat-spot, but now, with heavier town traffic, I am riding more and more at low speeds just using that part of the throttle constantly, rather than driving through it to a place where the carb is OK....
What are the "simplest" and "Best" solutions to my dilema? - I'm sure I'm not the first to need improvement of the factory tuning for low-speed urban use?
I see I can buy some 26mm PHBL carbs on e&@y for just over £50 each... Dell-Orto copies of for 125cc 4-stroke singles.... but will they be better for the "town" riding I now find myself doing more and more? The cost of buying lots of jets and slides from Dell-Orto suppliers for my carbs is seriously worth more than the expected improvement, which is probably something that is cast/drilled into the main body anyway...?
ebay.co.uk/itm/124813341223?3D%
I have found the bike to be "more reliable" than bikes I had in earlier life... But mostly because I needed reliability above performance for the commute to work. Guzzis are somehow endearing - with their quirks of the heavy throttle springs (Italian law = quick close), Italian law quick release side-stands, coupled braking, Italian police riding position and all the other things the press find to be "not Japanese" (I.E. Easy and finely tuned) ... But "That's why I like it!" - But now I need a town "crawler" so I can be smoother and easier (like I had with the many Japanese machines) without constantly de-clutching, revving - and now I have to clean the plugs often from the soot caused just off idle! - I'm just not riding on open roads every journey to burn away all the soot from the plugs.
Cheers!
Steamchick
Also, I couldn't find a "Model specific" V50II sub-site...? - Any suggestions?
I have owned a V50II for 23 years... used small-time for commuting and local trips... but until 2018 the commuting etc. was mostly 3 miles town/dual carriage-way, then a 3 mile blast at up to legal speeds (honestly, your honour...). But traffic had been getting very thick so in the last few years I had been spending more and more time trying to keep the idle working usefully, and minimising "pops" on over-run.
So retirement came, and I'm down to a couple of hundred miles a year (local town work mostly) - and have finally reached a fairly usable tick-over!
But the bike has always had a huge flat-spot below 2500rpm... where opening the throttle too much ay low revs (1500rpm~2500rpm) it makes a hell of a lot of intake noise with very little increase of performance.
Now I worked in engine design on cars back in the late 1980s~90s. I've been around engines and bikes for over 50 years, but am always willing to learn - especially about carbs - as I have never had to do much real carb tuning. (mostly "stock bikes and a lot of use", rather than "a lot of tuning and rarely used").
During recent pandemic restrictions I spent a bit of time studying the mixtures I get - because the bike doesn't suit the congested city driving I do mostly... which seldom gets to the 30mph limit, and when it does the speed cameras are everywhere!!! So this riding is a common thing for me now, so instead of blasting around at 1/2 throttle and up I am tootling along at barely a crack of throttle. Something the Original designers (nor I) ever envisaged for this bike.
The idle - being set, working and stable, and showing a good burn with the optimate (glass spark=plug), just doesn't like the throttle being open slightly. The mixture goes exceedingly rich until about 1/4 throttle - which I understand is the slide cut-away ratio along with the pick-up orifice just up-stream of the slide.
The bike has VHB carbs.
From 1/4 throttle upwards everything is fine, and in tune. Carbs have been cleaned, (Ultrasonic and chemical) and I am now sure all passages are as "originally intended".
I suspect the rich mixture - just off idle before the slide opens 1/4 or more - is a "fuel boost" to prevent the engine dying when pulling away moderately (The new experience for me..). I had learned (20-odd years ago) to feather the throttle to get past the flat-spot, but now, with heavier town traffic, I am riding more and more at low speeds just using that part of the throttle constantly, rather than driving through it to a place where the carb is OK....
What are the "simplest" and "Best" solutions to my dilema? - I'm sure I'm not the first to need improvement of the factory tuning for low-speed urban use?
I see I can buy some 26mm PHBL carbs on e&@y for just over £50 each... Dell-Orto copies of for 125cc 4-stroke singles.... but will they be better for the "town" riding I now find myself doing more and more? The cost of buying lots of jets and slides from Dell-Orto suppliers for my carbs is seriously worth more than the expected improvement, which is probably something that is cast/drilled into the main body anyway...?
ebay.co.uk/itm/124813341223?3D%
I have found the bike to be "more reliable" than bikes I had in earlier life... But mostly because I needed reliability above performance for the commute to work. Guzzis are somehow endearing - with their quirks of the heavy throttle springs (Italian law = quick close), Italian law quick release side-stands, coupled braking, Italian police riding position and all the other things the press find to be "not Japanese" (I.E. Easy and finely tuned) ... But "That's why I like it!" - But now I need a town "crawler" so I can be smoother and easier (like I had with the many Japanese machines) without constantly de-clutching, revving - and now I have to clean the plugs often from the soot caused just off idle! - I'm just not riding on open roads every journey to burn away all the soot from the plugs.
Cheers!
Steamchick