2639 Posted November 11, 2009 Report Share Posted November 11, 2009 Old GPz1100, 1982. DFI long gone, Mikiuni's now. Just fitted Dyna S. It's hardly turned a wheel for ages, indeed sat for over a year due to ignition hassle - so I sold the belt driven magneto and fitted Dyna S. Problem. It spits back through the carbs occaisionally, mostly at tickover, but also does it at mid revs too. Not sure about high since it never gets revved. It's not a regular thing though, it doesn't stick to 1 cyl, although 1 and 2 seem more prone to it at tickover, no idea if this changes up the revs. Its not constant. Sometimes it'll run clean for a 30 seconds then spit, 30 then spit, others it does it much more frequesntly. Plan/Solution.... The Dyna is timed as per the instructions, However does anyone have a sensible timing figure for the bike. Manual says 'leave the DFI alone'. Dyna instructions are for earlier Zeds - might be a mismatch here. Valve clearances. This could cause it to spit if the clearances have closed up, right? Cam timing, if it had got put backtogether a tooth out? Just possible it has slotted sprockets - don't think so - but. Air leaks - shouldn't be, new clips, good condition rubbers, correct carbs spacing - how would I check for sure? What else could cause intermittant spitting back through the carbs? I ask cos the R1 is so simple, and never goes wrong, forgotten the basics a bit. Cheers Andy Link to comment Share on other sites More sharing options...
fran9r Posted November 11, 2009 Report Share Posted November 11, 2009 Did it run properly with the old ignition? What Mikuni's are fitted, and have they been jetted to suit. Link to comment Share on other sites More sharing options...
tootall Posted November 11, 2009 Report Share Posted November 11, 2009 They all do that sir. Mine has exactly the same probs. Gpz1100b2 running carbs and pod filters. Standard ign though. I'm going to play around with some jets and needles tomorrow so will let you know how I get on. The trouble is that the carbs are usually from a z1 and not jetted right for the 11, and certainly not for pod filters. There's also a chance you've got gs1000 carbs on there, or gsxr750 so jetting could be way out. I'm hoping its a jetting prob rather than ign with mine. Link to comment Share on other sites More sharing options...
spacemonkey Posted November 11, 2009 Report Share Posted November 11, 2009 They all do that sir. Mine has exactly the same probs. Gpz1100b2 running carbs and pod filters. Standard ign though. I'm going to play around with some jets and needles tomorrow so will let you know how I get on. The trouble is that the carbs are usually from a z1 and not jetted right for the 11, and certainly not for pod filters. There's also a chance you've got gs1000 carbs on there, or gsxr750 so jetting could be way out. I'm hoping its a jetting prob rather than ign with mine. I think the igntion would have to be way out to cause that... Lean running sounds like suspect number one... Unless your camcam timing is out.... Is this happening under zero load? If so, start with bigger pilots. Link to comment Share on other sites More sharing options...
tootall Posted November 11, 2009 Report Share Posted November 11, 2009 I think the igntion would have to be way out to cause that... Lean running sounds like suspect number one... Unless your camcam timing is out.... Is this happening under zero load? If so, start with bigger pilots. Well, thats a bugger, not got any bigger pilots! Got a dynojet kit and thats it for the mo. Link to comment Share on other sites More sharing options...
2639 Posted November 11, 2009 Author Report Share Posted November 11, 2009 Did it run properly with the old ignition? What Mikuni's are fitted, and have they been jetted to suit. Define properly... it never really ran enough, it's didn't run at all since June 08 until 2 weeks ago. And stuff all in 06 and 07. I can't recall if iy spat back or not. I think it did, but not as much as now. It's got flatslides on it, Allens supplied some new slides and jets ti siut after a nitrous burp ate number 1 slide. They knew what I wanted and supplied bits / instructions. They're not GS etc carbs. That siad its thirsty. And seems smoky at the exhaust. Never been able to make inroads at getting it to run right as the mag was a menace for the street. Plan. Swing the ign back plate a few degrees. If it is only timing then retarding the ign should eliminate the spitting. Colour tune plug in each cyl. Compression test each cyl See if anything arises. Next step? Valve clearance check / check cam timing and see if cams are slotted. How would you test to see if the inlet stubs are leaking air? --------------------- Mines on pod filters, how should jetting be compensated? Should the spitting back change with filters on or off? Link to comment Share on other sites More sharing options...
Jay Posted November 11, 2009 Report Share Posted November 11, 2009 How would you test to see if the inlet stubs are leaking air? This would be my first guess, dunno how you check though other than taking them off and looking for cracks due to perishing. Link to comment Share on other sites More sharing options...
lorenzo Posted November 11, 2009 Report Share Posted November 11, 2009 Spray the inlet stubs with something flammable, wd40 or something, see if it changes the engines running and what not? Link to comment Share on other sites More sharing options...
spacemonkey Posted November 11, 2009 Report Share Posted November 11, 2009 Well, thats a bugger, not got any bigger pilots! Got a dynojet kit and thats it for the mo. Have you tried winding out the mixture screws as a bit of an experiment? For airleak testing I think the idea is to use something like WD40 that will seal the cracks for a few seconds but won't do any harm inside the motor.... You see if it runs better with WD all over it... Link to comment Share on other sites More sharing options...
fran9r Posted November 11, 2009 Report Share Posted November 11, 2009 Well, thats a bugger, not got any bigger pilots! Got a dynojet kit and thats it for the mo. How to cure all those prob in 3 easy steps. Step 1: Locate bin Step 2: Place all dynojet products in bin. Step 3: Purchase new pilots. Link to comment Share on other sites More sharing options...
fran9r Posted November 11, 2009 Report Share Posted November 11, 2009 Define properly... it never really ran enough, it's didn't run at all since June 08 until 2 weeks ago. And stuff all in 06 and 07. I can't recall if iy spat back or not. I think it did, but not as much as now. It's got flatslides on it, Allens supplied some new slides and jets ti siut after a nitrous burp ate number 1 slide. They knew what I wanted and supplied bits / instructions. They're not GS etc carbs. That siad its thirsty. And seems smoky at the exhaust. Never been able to make inroads at getting it to run right as the mag was a menace for the street. Plan. Swing the ign back plate a few degrees. If it is only timing then retarding the ign should eliminate the spitting. Colour tune plug in each cyl. Compression test each cyl See if anything arises. Next step? Valve clearance check / check cam timing and see if cams are slotted. How would you test to see if the inlet stubs are leaking air? --------------------- Mines on pod filters, how should jetting be compensated? Should the spitting back change with filters on or off? Yep your going about it the right way with proper carbs. CVs don't have availability of parts. Check the timing just to make sure, there is no point playing with the jetting to then find the timing is incorrect. Then you can start with pilots. Once that is done, check the plugs. May be worth some dyno time too. Link to comment Share on other sites More sharing options...
Number 6 Posted November 12, 2009 Report Share Posted November 12, 2009 Did you set up the ignition using a test light? Also maybe a stupid question but did you use fresh fuel? you say the bikes sat for a year Have you cleaned the carbs since it's been sat? Are you running stacks or filters? Link to comment Share on other sites More sharing options...
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