commando carb on honda

My Commando Amal MK2 34mm carb was on the shelf, removed because it didnt prove good, poor tickover etc.
I have a Honda pc800 [dont :lol: ] they are a fantastic engine...some covering 300,000 miles...200000 common ,,,anyway the pc was crap running, it would'nt rev up above 1500 rpm...purchased like that...i though a carb clean and its a go'er? NO no the carbs cleaned and the engine was no better..
Now heres the interesting bit: i stripped out the original carbs and made up a mainfold the take the commando amal, as the tank is low in the frame fuel is pumped up.
So when my mate turned up i asked him the hold the carb in his hand upright while i checked the float would seal against the pressurized supply. i connected the fual line and turned on the power ..The carb held the fuel in check, and no flooding!
So i said to my mate "just hold the carb onto the manifold! bare in mind there is no rubber connector ,the carb is just placed near the inlet with a gap between the carb and manifold, the gap is 10-15 thou ..the Honda FIRED up!!! and ticked over fantasticly :roll: better than the norton had ever done...Well "we" where just blow away at this...an engine ticking over with NO rubber connector! Just held near enough in my mate's hand :!: All the Forum posts about carb-inlet air leaks :!:
Must admit the PC 800 is a tractor 40 odd brake ,7500 top RPM ...next the see if it will run on heating oil, dribbled in with a can :lol:

anyway the pc was crap running, it would'nt rev up above 1500 rpm

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If its a CV carb those are classic symptoms of a punctured diafram.

The bike is a cal-aforni model with 500 feet of pipe work, 50 Evap valves ,evap caniaster, total un adjustable , more drilled and plugged passageways than the London underground! The original carbs are set super LEAN, and slight gumming causes mayhem! Diaphrams are ok and going on ebay!

Well what do ya know John but crazy experiments that lead the way to new insights or just how fussy a Commando engine is on its fueling compared to the Honda or the Amal 2 has too much idle fuel flow for either engine unless its leaking extra air. Your state of mind to try this is entertaining-confusing, hm didn't work on Commando so will it on something else...
Loved your description of the smog proofing plumbing we are fortunate to miss out on old Norton polluters. Might have to diddle tunes at some point as radiation levels increases air ionization and O2 levels fall.
https://www.google.com/#psj=1&q=oxygen+ ... decreasing

Steve

I have noticed the carb as a lot of Suck, maytby less on Norton :?: High depresion advantages , i guess the Commando would start /idle better with small carb? which means the top end will suffer but more torque . Ford built small port engines for tractorbility , if the vacuum is high the gas speed increases and pulls hard on fuel meters...causing better mixture..its like a rattle can running out of pressure...end results is dribbles! The triumph saint {single smaller carb] was 5 mph slower compared to the bigger twin carb Bonneville, but the saint was a Saint to tune/ride.

hobot said:

Well what do ya know John but crazy experiments that lead the way to new insights or just how fussy a Commando engine is on its fueling compared to the Honda or the Amal 2 has too much idle fuel flow for either engine unless its leaking extra air. Your state of mind to try this is entertaining-confusing, hm didn't work on Commando so will it on something else...
Loved your description of the smog proofing plumbing we are fortunate to miss out on old Norton polluters. Might have to diddle tunes at some point as radiation levels increases air ionization and O2 levels fall.
https://www.google.com/#psj=1&q=oxygen+ ... decreasing

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I have noticed the carb as a lot of Suck, maytby less on Norton :?: High depresion advantages , i guess the Commando would start /idle better with small carb? which means the top end will suffer but more torque . Ford built small port engines for tractorbility , if the vacuum is high the gas speed increases and pulls hard on fuel meters...causing better mixture..its like a rattle can running out of pressure...end results is dribbles! The triumph saint {single smaller carb] was 5 mph slower compared to the bigger twin carb Bonneville, but the saint was a Saint to tune/ride.

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Hmuphf, Ya know there's a saying that applies here ... "If it ain't Blown, then it just Sucks"

john robert bould said:

The bike is a cal-aforni model with 500 feet of pipe work, 50 Evap valves ,evap caniaster, total un adjustable , more drilled and plugged passageways than the London underground! The original carbs are set super LEAN, and slight gumming causes mayhem! Diaphrams are ok and going on ebay!

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I used to have a Honda NX 650 thumper that was a California model, it had all of that emission crapola on it too. It took a bit of doing as I recall, but I got it to run well after removing all of that stuff. But what a pain in the neck , as I was stationed out in Guam at the time -- think lots of time waiting on the postal service.

John,

I've had some carbs that really sucked over the years

I'm not sure your test is really what you think. It's possible to get engines to run in all sorts of strange ways. Back in the early drag racing days we even put fuel lines directly into the intake ports and ran down the track...had a few fires but it worked. The real question is how would the engine perform with that carb properly mounted and run through the range of performance from idle thru all throttle positions and then under load. My guess is the result would not be very good...or you are one very lucky guy. Tuning is an art particularly when fitting different carbs or performance modifications.

How would he actually get the Amal to be roadworthy, duh, just mount with spacers for enough air gap and wrap some filter around the area, sheeze. There's tales of people with campers getting back with propane tank in the cab and hose to carb with some funny throttle practice worked till tank frooze up for a wait to warm again and keep on chug a lugging. I've kept V8's going a while just dribble gas in carb when it had fuel blocked or no fuel. Of course I don't expect that crudeness to run a Commando beyond some hick ups.

hobot said:

How would he actually get the Amal to be roadworthy, duh, just mount with spacers for enough air gap and wrap some filter around the area, sheeze. There's tales of people with campers getting back with propane tank in the cab and hose to carb with some funny throttle practice worked till tank frooze up for a wait to warm again and keep on chug a lugging. I've kept V8's going a while just dribble gas in carb when it had fuel blocked or no fuel. Of course I don't expect that crudeness to run a Commando beyond some hick ups.

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If it's just amazing that the Honda ran, I get that, but would it really run?

Its more amazing John would even try what he did and of course about flabbergasting he'd admit it and claim the Honda started and idled fine. Like the fella saying he pulled up an ancient lamp while fishing and the thing was still lit! John you got us going on your Amal connected saga so don't let us wait too long for the other shoe to drop. I've had Amal bowel hanging down on half of one screw hold splashing fuel out yet only noticed I had to stay on throttle more to run responsively and also gasket hanging completely free under a carb yet only some missfires stumbles till some normal range throttle felt fine and of course not notices on let off but intersting bubble/pops out muffler. Logic says if run ok with air gap may tend to flood once sealed up, so fit smaller pilot jet and Honda around.