Home › Forums › Motorcycle help wanted › Poorly GPX600r
- This topic has 15 replies, 5 voices, and was last updated 14 years, 10 months ago by Radar.
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- January 29, 2010 at 5:26 pm #14042notlob64Participant
Right then…Where do I start.
A few months ago my 1988 GPX600r (21k on the clock) developed a problem with acceleration when petrol went onto reserve. i thought at the time that one of the fuel pipes was possibly creased due to me having the tank off to change the steering head bearings. I checked this and were no creases so just made sure that i didn’t fall into reserve. Well the problem started to happen when the tank was a quarter full so a couple of weeks ago I drained the tank and guess what….a load of rusty type crap came out. Since then it doesn’t seem to be firing properly. I have changed the plugs and today have had the carbs off and cleaned the bowls and checked the jets and all seem quite clean to me. Put them back on and still not firing right. Seems to not be missing (have checked for sparks on all 4 plugs and all ok) just sounds sluggish and runs poorly at low and high speed. There is no damage to any of the fuel pipes or vacuum pipes, the fuel filter seems ok and clean.
Anyone got any ideas of what i can look at next – Thanks Tonyps – if the valve clearances arn’t right would this cause the above, although i do feel it’s something to do with the fuel intake due to everything being ok before the dirty tank…[]
January 29, 2010 at 8:45 pm #60231HippoDronesParticipantis there a diaphragm after the fuel tank but before the carb?
January 29, 2010 at 8:59 pm #60232notlob64Participanthi Pete…
no just a fuel line and a vacuum line into the filter
January 29, 2010 at 9:23 pm #60233imperialdataKeymasterHad the carbs off my GPZ a few months back, I’m pretty sure the arrangement is the same on your GPX. Very likely the rusty crap has made its way south…..
I’d take the carbs off again and clean the fuel shut-off valves (float valves) which need to shut fully to avoid flooding. Check their height with feelers but it’s unlikely they will need adjustment unless knocked. Remove the jets and blow them through. After all those years of unleaded fuel, you’ll probably be moving some crap around the carbs so a couple of clean-outs is normal.
You can check the diaphragms as well while you’re there, always worth a look for tears or splits.
I put a fuel filter from a large Suzuki onto my line from the tank to carbs. This was a big enough flow rate to cope with the GPZ (important) and allowed for some trapping of tank crap where required. Filter was about £6.
Check the vacuum pipe from the tank is not split or kinked, this draws the fuel through the system when not on ‘prime’.
I’d stick a fuel tap repair kit on after a good clean-out too, worth it for a few quid.
Hope this helps!
January 29, 2010 at 11:23 pm #60234RadarModeratorI was going to suggeat an in line filter too funnily enough. I would also clean the tank again and consider buying one of those tank sealing gels to prevent any further debris/rust getting into the system
January 30, 2010 at 12:15 am #60235RadarModeratorThis link might be useful too
January 30, 2010 at 9:26 pm #60236notlob64ParticipantOdd question and maybe slightly embarrassing, but would having Redex in my tank have any cause for the above. I think maybe !!!
January 30, 2010 at 10:13 pm #60237RadarModeratorI dont think it would to be honest, but have you tried it without and the bike run ok?
January 31, 2010 at 10:17 am #60238imperialdataKeymasterThe newer Redex stuff for cleaning injectors/carbs or the older one for ‘decoking’? The carb cleaning one will doubtless be shifting some crap around and it doesn’t take much to block a jet or float valve seat.
January 31, 2010 at 3:44 pm #60239RadarModeratorquote:
Originally posted by imperialdataThe newer Redex stuff for cleaning injectors/carbs or the older one for ‘decoking’? The carb cleaning one will doubtless be shifting some crap around and it doesn’t take much to block a jet or float valve seat.
Good point ID
January 31, 2010 at 3:49 pm #60240notlob64ParticipantIt’s the older Redex i used. taken the carbs off again and they seem fine. draining the tank again and rechecking the filter. A mate from work has mentioned an Italian cleaner (can’t think on the name) say’s it shifts anything…Any idea?
February 1, 2010 at 6:05 pm #60241imperialdataKeymasterLocal bike shop recommended Motrax carb cleaner to me. Ultrasonic bath is worth doing if you want to be sure. I think ‘Katana’ on here would recommend them and maybe tell you a bit more about them.
February 2, 2010 at 9:10 pm #60242katanaParticipantUltrasonic is definatlely the way to go. Even then I had to clean the blades carbs out a couple of times before I got rid of everything.
have a look at at the results here:
https://bikemeet.net/forums/topic/the-new-project-1994-fireblade/If you can get your carbs over to Evesham I’ll stick them in my Ultrasonic for you.
February 3, 2010 at 7:22 pm #60243notlob64ParticipantStill not fixed. Went to work on it today and it sounded like a bleeding taxi…There is one thing I have noticed however. When i start him up with the choke on there is a few ‘pops’ coming out of one of the exhausts. Any ideas ? Thanks for all your suggestions up to now chaps. i will take the carbs off again and completely strip down soon – Tony
February 3, 2010 at 11:39 pm #60244RadarModeratorWhen did you last balance the carbs?
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