fromos Posted September 18, 2012 Share Posted September 18, 2012 Hey guys got a problem there i have a opportunity to buy a 1981 Suzuki gs 450 s when I went for my visit i tried out the bike and it was running great up and down the road but then next thing it cuts out and backfires.I tried to start it up but it wouldn't run so we left it to cool down for bit then she started again.The problem is when it gets warm it then cuts out im not an expert on bikes but i like the bike its condition in general is pretty dam good its just that problem there is a few things ive guessed it could be starter coil pack,letting in rich juice or possibly the floats or needles into the carb being bent or have some debris on them or possibly the sparkies but they are only 6 months old but then again its been sat outdoors for a while any ideas would be good.its a twin and has normal air box no k,ns it starts great runs great just cuts out say 5 mins of riding or just ticking over simple fix or serious? cheers dave. Quote Link to comment Share on other sites More sharing options...
Fozzie Posted September 19, 2012 Share Posted September 19, 2012 I'm dubious about it being fuelling for some reason...When it warms up it should evaporate the fuel with greater ease and in fact run better!A coil could be heating up as I know a couple of cars and bikes that warmed up and as they did the coil pack got hot and failed, however it worked at low temps. So a good starting point would be to assume the bike has a coil issue.If it runs well right up until it warms up then its unlikely to be fuelling unless its something daft like the carb inlet rubbers heat up, expand and show off lovely cracks.Check the fuelling system first for good measure as it always gets a bike running nicely.I would then check the coils to see if they are failing when warm!And if both fail, check back here and we'll move on as you'll find more symptoms as you go. Quote Link to comment Share on other sites More sharing options...
mattycoops43 Posted September 19, 2012 Share Posted September 19, 2012 Don't buy it unless it's REALLY cheap!I had a gs550 il4 and it wouldn't run right, nobody including a tuning shop could get it sorted, if it's a carb issue, unless you are happy switching to different carbs, there can be major issues with cost of some carb components on old suzuki's. Depends how much you want to fiddle. Quote Link to comment Share on other sites More sharing options...
Mrbarry Posted September 19, 2012 Share Posted September 19, 2012 Could be a million things, as said unless its almost free then walk away. If something seems too good to be true then inevitably it normaly is!It sounds fuel related and could just be running rich, but if it's been rich for long the bores will be trashed anyway so still walk unless you compression test it first (when hot) Could also be many other things. Quote Link to comment Share on other sites More sharing options...
fromos Posted September 19, 2012 Author Share Posted September 19, 2012 Cheers guys how would I check the coil pack ? Its been sat outdoors for a while like but with a cover he has good set of sparks which are only 6-9 months old could it be that at all the carb issues sounds far fetched to me aswell the coil pack is proberly the same age as the bike 1981 so its easy to assume its that is there a easy way of testing the pack out ? Cheers Quote Link to comment Share on other sites More sharing options...
oslin06 Posted September 22, 2012 Share Posted September 22, 2012 You know Fromos if you listed on your profile where you are, someone local may be able to come alomg and help you !!Keith Quote Link to comment Share on other sites More sharing options...
dave8204 Posted September 23, 2012 Share Posted September 23, 2012 Bikes of that age can be money pits no matter how cheap the seem to be.Up to the seller to make sure it's in good working order and legal before selling it,and one of those isn't worth a lot anyway no matter how good.Tell him to sort it and you'll come back for another test ride when he was.....or just walk. Quote Link to comment Share on other sites More sharing options...
fromos Posted September 25, 2012 Author Share Posted September 25, 2012 Hey guys thanks for the advice I took one of my mates to see the bike so forget it being elctrical the carbs needed cleaning and that was all sober got it for £180 as is and it needed front break pads and a petrol filter it cost me 20 quid with the parts came with log book lee Haynes Manuel etc made up haha runs fantastic thanks for the advice guys Quote Link to comment Share on other sites More sharing options...
mattycoops43 Posted September 25, 2012 Share Posted September 25, 2012 Glad you got it sorted! Should be a good little runner. Quote Link to comment Share on other sites More sharing options...
Tango Posted September 26, 2012 Share Posted September 26, 2012 Nice one mate......bit of a bargain.....enjoy it...... Quote Link to comment Share on other sites More sharing options...
fromos Posted October 2, 2012 Author Share Posted October 2, 2012 Okay had it running for a bit that day 30 minutes and haven't road it and where back to square one my friends a mechanic and even hes baffled by it he is pretty sure its electrical hes cleaned the carbs and there spotless now and there's no rubbish getting through now due to the inline fuel filter i went round again today with a different coil pack (used but working) and tried that and again it cut out within the five minutes we checked the new ignition switch that had been put on before we bought it nothing out of the ordinary there checked all the wiring to see if anything was out of place everything seems fine it starts and runs really decent until it gets to a warm tempature and then it cuts out as if someone has hit the emergency switch so we checked that and cleaned all connections and same again just dies i don't no mass amounts about bikes where he knows quite a bit when we checked the original coil packs they should of read 23-25and one side read like 10 and the other 33 i spoke to a fella who owns a motorbike shop near mine he mainly fix's Suzuki he said that it sounds like either the original bikes coil pack or the cdi unit he was pretty sure of it but when a cdi unit is faulty would it even work at all ? any help would be amazing also a post up the top i am based in Liverpool. Quote Link to comment Share on other sites More sharing options...
Fozzie Posted October 8, 2012 Share Posted October 8, 2012 Change the CDI and the coils for new ones On some cars and bikes ive known there has been a problem where the coils go but cause damage to backfire up the line and blow the ECU or a CDI.Prime example was a Fiat punto that did this. Ran fine while it was cold, but when it warmed up its mapping changed but because of its damage it didnt fuel the car correctly and that is what caused the issue.A CDI is much more simple as it doesnt change mapping, however it can still be damaged and bugger up the ignition. Quote Link to comment Share on other sites More sharing options...
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