Working on Honda Spada. All electrics functioning, big fat spark on both plugs, carbs disassembled, comprehensively cleaned.. still running smoothly only on rear cylinder, not a backfire, pop, stutter, absolutely no life on front cylinder.. only 24,000 kms on bike. Also changed front plug.. I’m wondering if valve closure or something similar could be the culprit.. any ideas, never seen this on a Spada before,,, also changed black box for known good one.
Compression would be the obvious one to check. If it's toasted properly, you may be able to hear that only one cylinder alone has compression when turning it over on the starter. If it's as dead as a dead thing I'd be checking that the cams are turning on that head. Do they have separate cam drives to each head or is it common? Helpful to know when the problem started.
Yep, see Cams turning, cam chain nice n tight, valves within spec, sparking, fuel present, going to have to find the compression tester I guess. History is the owner was riding to me yesterday, bike cut onto one cylinder on the way and that's the condition it arrived to me in. He reckons it had be en parked outside at his place for 10 years, he has cleaned out tank, installed iradium plugs, replaced regulator, oil etc. Registered it, put a few thousand kms on it, its had an irregular idle and a pronounced flat spot. He did tell me he put a bottle and a half of fuel injector cleaner in the tank, realised the error of his ways after riding it for a while, flushed the tank out and refilled with fresh fuel..The dead cylinder is pumping air out the sparkplug hole when turned over. I have a brand new set of spada carbs, i'm still suspecting a carb issue, first job if I can"t find compression tester and adaptors this morning will be to fit new carbs and see if these bring the front cylinder back to life. I did blow compressed air through all air passages, set float heights, clean and check jets,(carb cleaner and hydrasonic clean and visually inspect), clean out float bowls which were filthy.
Blocked jets judging by that buildup in the float bowl, probably blocked passageways in the carb body, too.
Yep, I agree, except I’ve already disassembled carbs, cleaned jets, blown compressed air through all airways etc, etc..just about to fit my good, “carb testing “ set of carbs to see if that cures the problem..
Yep, already installed normal plugs, I reckon in a little commuter bike iradium plugs are a waste of money
Does the plug get wet from fuel on the dead cylinder? Can you see atomised fuel being sucked into the engine when you open the throttle (need tank and air cleaner removed)?
I’m stumped. Took carbs off again, blew all air passages out again, then looked inside idle jet and there was no clear passage.. cleaned it , again. Put bike back together and this time the problematic cylinder fired,,,,and the other one didn’t.. took around 3 mins of one cylinder running and it burst back into life. Been running perfectly since but WOW,, anyway, seems all good now.
No, fuel feed was a 250mm gravity bottle.. I wondered if , maybe there was crap inside the fuel pipe that locates between both carbs and supplies them with fuel.. but the front cylinder was totally dead, no splutters or signs of life,, and everything that’s usually the problem had been thoroughly cleaned once already. Anyway,, all running well now. It’s actually a great motor, only has 25,000 kms on it. Thanks everyone for your ideas and suggestions.
Yep, still waiting on parts to get mine going. I am getting a bit sick of looking at it in the garage with no engine in it.
The VT250F has two TCI boxes (one for each coil/cylinder). Weird setup. Is the Spada the same? @jmw76 I hear you buddy. I've been waiting for ages for some bits from OS. Even the tracking systems aren't working properly. I contacted a seller to cancel my order because the tracking said the items were still in the country of origin. The seller refused to give me a refund and asked if I could wait a little longer. The next day the goods arrived? Normally, I get SMS messages saying "they're on there way" or "have been delivered"... nothing!
Yep, postage is a total, random mystery atm. USA tracking info is based on where the parcel should be, not where it actually is. Recent battery delivery from Sydney supplier arrived in 18 hours by courier, recent fuel tank from India arrived in 7 days.. recent delivery from Bombaderry to sutherland took 15 days.. no rhyme or reason.
Did you check both Pulse generator connections? Although I think you mentioned you had spark on the front but I could also be wrong...lol
Yep, spark was perfect.. outside chance it was happening at the wrong time , replaced tci box and had a look at ignition pickups which appeared as they should be ,made no improvement. 2nd carb clean seems to have resolved all issues, purring like a kitten atm and running beautifully.
Agreed, postage is all over the place. I've had to cancel some O/S orders as the tracking said they were still in the country of origin after 2 months. Yet other stuff I bought through Aliexpress has arrived really quickly and with constant tracking updates. I got a deal on some panniers in Brisbane. Tracking said they were still sitting at the post office in Brisbane after 3 1/2 weeks. Had to put in an investigation on them. Next day they arrived. My son finished his advanced diploma course with a uni in Canberra. They have sent his certifications in the mail 3 times and never arrived - done over a period of 3 months. So luckily a friend of mine in Canberra, went to the Uni, waited until they printed the certifications again and has now put them in the mail to us, registered with tracking. I've received emails from Auspost saying that the problem is the lack of air-flights to transport the mail.. all due to Covid19.