80s honda Spada

[K1GxR]

hi there

i have an 80s model Honda spada sitting in my backyard. (forced air brakes thing) it's been sitting around for many years, been bought over and we managed to get it running (after rebuilding the carbs). however it does not run right, and seems to be lean on fuel, or the throttle mechanism is stuck. The guy that promised to fix it for me is nowhere in sight.

1. revving up the revs take a while to drop down
2. take it down the road and open up the throttle it runs as if it's got a 50cc motor on it, utterly gutless. hardly get out of 1st gear. doesn't splutter or misfire or anything, just gutless
3. reasonably easy to start. fresh fuel, starts pretty much the first go everytime. i start it every week or so

i'm hopeless with jets and carb tuning but i'm guessing this is a carb issue.

is there any knowledgable soul out there that knows something about this bike and can maybe lend a hand for some cash, beer etc?

[thro]

Sounds like fuel starvation to me - checked the fuel filter(s)?


If its been sitting a long time with an empty tank it could have a heap of rust in the tank which will be clogging both the filter in the fuel petcock and/or the inline fuel filter(s) on the way to the carbs....


I suspect that carb *tuning* isn't really the issue - they don't magically go out of tune by sitting there, my money is on fuel blockage somewhere.

[Rocky]

I had one of these and I had an issue with the fuel delivery too. It was a wonderful bike though, as that was the only issue it gave me, and it turned out to be a bit of dirt in one of the carbs, as it would gradually run dry and die.
It might be an idea to check how much fuel is in the visible filter that sits just under the seat (forget which side). Sometimes people take them out and connect the two lines, but if it's there it might give you an idea whether it's a fuel problem or not.

[K1GxR]

carbs been rebuilt so its not the carbs

plus the amount of fuel that comes out of the tank through the fuel lines, i doubt it's fuel starvation from the tank. i'll check it out anyway

but yea still need someone to set up the carbs because they have been rebuilt but the jets i believe are wrong.

other reason i suspect it is the carb is because it has parts from 2 carbs (best of 2 put together), needle position, float level, jets i think are wrong, plus it's not balanced.

[Loud]

Spark. Fuel. Compression. No sense focussing on tuning until you've ascertained the rest is okay.

[darkfibre]

but yea still need someone to set up the carbs because they have been rebuilt but the jets i believe are wrong.

other reason i suspect it is the carb is because it has parts from 2 carbs (best of 2 put together), needle position, float level, jets i think are wrong, plus it's not balanced.

I would confirm that the jets are correct, as you can spend a long time beating around the bush getting nowhere if they are wrong.

And if the person who 'rebuilt' the carbs is not methodical enough to have made some sort of foolproof procedure to know where each jet belongs, I would get all of their carb work rechecked.

[K1GxR]

carbs was rebuilt by experienced mechanic

jets should be correct, as we had 2 different sets of carbs for this bike to play with both had the same jets.

had a look at fuel delivery, lines look good and filter has fuel in it, fuel going to carb is pretty much pissing in, not trickling inconsistently so i'd say that's ok. at this stage it looks like it needs adjustment. it starts first go everytime now, and can rev high in neutral though it feels very lean.

[smitto81]

maybe look at how well the airbox/airfilter is attached to the carbs. it will idle fine but without the vacuum effect from the air filter, the carbs cant suck the fuel they need

[Falcore]

make sure no leaks in the boots between the carb (are these cingle cyl?) easy to change coil, lead an plug? could never hurt

valve clearances? done a compression check?

[K1GxR]

yeap V twin, 2 carbs

boots are ok. coils and leads are visibly alright, spark plugs are new. it's not arcing out and the bike is not misfiring or any indication of an electrical fault. free revving can be revved high but sounds sluggish at higher rpms. idle and low rev is fine. take it down the road and the top speed is consistently 60 km/h at best, feels like the motor is very underpowered or the bike is very heavy.

will give all them a go anyway doesn't hurt to test and swap.