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proskaterdp

Joined:

Aug 12

Posts: 10

proskaterdp says:

bike cuts out

my 1988 honda bros is cutting out. its been uber reliable but recently has been cutting out when riding it. it will run for hours but sometimes out of the blue will cut out. no matter how long i hold the throttle on for it will still cut out. it will then promptly start and run fine for a while and then cut out again. i was thinking it could be dirty fuel but its gone through about 3 tanks of fuel now and its still doing it. ive also noticed fuel coming out of the filler cap as if the tank has been pressurized? i dont think its electrical although i have had some issues in the past. its very strange and no one knows why its doing it?

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  • Posted 2 years ago (15 July 2013 16:49)

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kcmc

Joined:

Jan 08

Posts: 7549

kcmc says:

Honda Bros 1988??--400 or 650?

Hi Proskaterdp

A 25 year old japanese market gray import bike with a intermittent cutting out problem could be difficult to track down on the bench let alone over a post on the net,so you may need to take it to a bike only repair shop if you don't know where to start(check the fuel tank breather is free from debris?,could be rust in the fuel tank blocking the fuel tap filter?check the battery terminals are tight and free from corrosion?could be lots more other faults with a bike of this vintage).Good Luck

KCMC:tongue:

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proskaterdp

Joined:

Aug 12

Posts: 10

proskaterdp says:

honda bros 650

hi KCMC, thanks for your reply. im reasonably competent at doing the work my self. ive had this bike apart quite a few times and quite a few of my friends are mechanics, ive also asked a couple of local bike mechanics who cant provide me with an awnser. its the sort of thing they could spend weeks on and then never find a solution either.

 i was thinking it could be electrical but its strange how it  starts and runs great again after cutting out. you would think if its an electrical fault it would stop and not work again.
i did at first also recon it was dirty fuel but you would think that would have cleared by now. and if it was something in the carb it would drop onto one carb and run on one cylinder?
the main clue i can see to what it is is that its blowing fuel out of the filler cap when the fuel tank is full. it only does this when it starts to cut out. it also seems to cut out more often after giving it a bit of hard throttle but it has done it at cruising speeds too. you can tell when its going to do it cos it runs crappy for a couple of secs and no mater what you do (hold throttle on or back of) it cuts out then starts again after a couple of secs?

the only thing i could think of is that its somehow building a positive pressure in the tank which starves both carbs of fuel meaning the engine would cut out but then it releases the pressure allowing the engine to run again. would this make sense and what do you think would cause this to happen?there is also a sticky red residue i have found around the air filter in the air box? i did 300 miles the other day and the bike ran like a dream until 10 miles from home. its driving me mad! thanks guys i appreciate any reply!:blink:

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kcmc

Joined:

Jan 08

Posts: 7549

kcmc says:

Honda NT 650V Bros 1988

Hi again

As you are competent with carrying out your own work,it sounds like you're going to have to go through everything to find this problem.Only advice i can give is as i said before,check the fuel tank breath as this could be the reason for the fuel is spewing out of the filler cap?.Also could be a fuel pump problem or a fuel cut out relay problem?can also be a poor connection from the pulse generator(corrosion etc?)(infact check all the main electrical connections)don't think it would be a defective pulse generator as if i remember the 650 has two,so would only go off on one cylinder.Has it got its original exhaust still fitted?if so?it is not a commen problem but does happen with these old exhaust,the baffles collapse,and ever so often a piece of the old baffle flips up and blocks the exhaust effectively suffocating the engine and stopping it,then the piece of baffle falls back into the bottom of the collector box having no exhaust pressure to hold it there,and the bike starts like there was nothing wrong.anyway something to think about and keep you busy:biggrin: Good Luck 

KCMC:tongue:     

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proskaterdp

Joined:

Aug 12

Posts: 10

proskaterdp says:

thanks

thanks kcmc, that's some pretty sound advice.ill run through all the major connections and check the breather.ur right on my model there is 2 generator coils.its an aftermarket exhuast but that's interesting about the standard one.but just out of interest would having an aftermarket one affect the fueling?thanks for your advise anyway and I'll let you know how I get on when I get the time to sort it out.

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