Harry66 Posted September 21, 2019 Share Posted September 21, 2019 Hi folks, still can't get the old slabby to pull cleanly. Had the carbs stripped by Allan's. Changed coils. Starts fine. Stutters at 6. Barely runs past 9. Vacuum fuel tap doesn't work on On. Use on prime. Could this be it? Is there a fuel filter somewhere that could be blocked? Plugs changed 4 years ago, but mostly parked since. Less than 1,000 miles. Could be one gone? Any suggestions welcome! Cheers Harry Quote Link to comment
canamant Posted September 21, 2019 Share Posted September 21, 2019 Daft question. Have you changed anything like airbox or filters ? What do you mean by carbs stripped ? Just stripped and re-assembled with the same bits or were new jets,needles, float valves, O rings fitted ? I'm assuming that you hav ethe standard VM29ss fitted. Easiest is try an old set of known good plugs to eliminate the plug possibility. Slabby Racer 1 and Slabby racer 2 both run standard Suzuki ON/OFF non vacuum taps. Try disconnecting the vacuum line if you have a vacuum tap and plug the carb so one carb isn't running weak. It might just be gummed up if it's been standing for 4 years so an Italian tune up might help. What was it like before you parked it up ? Is the fuel fresh ? (don't laugh - I've seen that one before !) The stutter at 6k is not unusual with some exhaust /filter combinations. Sorry it's more questions than answers Quote Link to comment
Harry66 Posted September 22, 2019 Author Share Posted September 22, 2019 Nice one. Good questions thx. Carbs are STD 29s. They were fully taken apart with various seals, needles and jets changed. STD 90 mains. They also have a rig to test and balance. I also bought a second set bored to 32 that I tried with the same results. I would not the carbs. STD airbox. Exhaust is laser end with who knows what downpipe. I fitted STD pipe, same problem. I had the fuel tap on prime, and would have thought the bowls had enough to rev up ok before starving? Not sure though. I don't know what the second into the carbs does. Is it overflow? I changed the coils thinking must be electrical. Could plugs break down so soon? I have used it each year, just not much. Clean fuel. Was running sort of ok last year. A bit rough mid but nothing like now. Next step buy other plugs. I also have a slave fuel tank to see if it is fuel tap. Just wondering what I have missed? Quote Link to comment
canamant Posted September 22, 2019 Share Posted September 22, 2019 90s are a bit small for VM29ss - I'll just check All prime does is push in the diapragm manually on a ramp - same effect as carb vacuum. Hou could just try disconnecting the fuel hose from the carbs and check the flow on prime.. I'm not sure what are vacuum pipes and what are vent pipes on the carbs when you have a vac tap set up as mine ar e factory fitted ON/OFF/RES taps.. I'll have a look at a set of carbs in a minute nd see if I can work it out. Just going out to the workshop for a root around. Quote Link to comment
canamant Posted September 22, 2019 Share Posted September 22, 2019 Main jet should be 97.5 so 90s will be lean. Also if you have a different filter to standard in the airbox that might make it even leaner which would exacerbate the problem. The 2 black T pieces beteween carbs 1/2 and 3/4 appear to be vent lines. Mine are just open with no hoses on the race bike carbs (VM29SS with 33mm face plates). I've just put a piece of tube on each one on a spare set of good carbs, sealed each pair of carbs and sucked. No vacuum generated. I'd think that the vacuum would have to be taken from one of the carb balancing plugs on the engine side of one of the carbs - thats where it has been on all vac tapped bikes I've had in the past - but you can eliminate the vacuum by doing the flow check on prime. Just a thought - have you ridden it and had these sysmptoms or just revved it up ? What jets are in the carbs with the bored faceplates ? Can't think of much else unless the Ignitor is packing up. I hope someone else can help further. Quote Link to comment
Harry66 Posted September 22, 2019 Author Share Posted September 22, 2019 Ah, bugger. I put the wrong mains in. The other carbs had 120 in. Same problem. Makes me think something electrical find. Then put the right size mains. Anyone know a dyno near Bedford who can help me set this up/fix it? Thx for your help . Quote Link to comment
Ronny Posted September 22, 2019 Share Posted September 22, 2019 Not a million miles from Bedford - Cooperized in Feltham. Quote Link to comment
p4ddy Posted September 23, 2019 Share Posted September 23, 2019 Id get stock jets first of cheapbay before spending out on a Dyno. Quote Link to comment
Harry66 Posted January 18, 2020 Author Share Posted January 18, 2020 Only taken me 4 months to get ... Seems it was de plugs. Fitted new. Fuel tap fine on prime and seems ok on On too. Changed the mains to 97.5 just so standard. Starts on the button, first time since u had it. Idles nice. And a trash up the road seems to pull cleanly Beer o'clock 2 Quote Link to comment
wsn03 Posted January 23, 2020 Share Posted January 23, 2020 That is bizarre! I had a similar issue with a 1200 Bandit years ago, really crap mechanic told me to change the plugs which had done sod all miles. It worked?! Quote Link to comment
davecara Posted January 23, 2020 Share Posted January 23, 2020 1 hour ago, wsn03 said: That is bizarre! I had a similar issue with a 1200 Bandit years ago, really crap mechanic told me to change the plugs which had done sod all miles. It worked?! Wasn't that crap then! 1 Quote Link to comment
wsn03 Posted January 23, 2020 Share Posted January 23, 2020 3 hours ago, davecara said: Wasn't that crap then! Quote Link to comment
kiwisuzuki1100nz Posted January 24, 2020 Share Posted January 24, 2020 wow. Good lesson to learn and noted. Start with the basics and trust nothing Quote Link to comment
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