Vintage Grumble Posted September 7, 2011 Share Posted September 7, 2011 Hi! The old 12R has a problem, at open road speeds it surges slightly, and it has decided it wont idle at all, and choke seems to have no effect when cold. what is the most likely cause of this? Just a bit of shit in a jet? I tried winding the idle up a fair bit to get it to run, and it will start with a bit of welly, and run at a high idle, but fades out an dies after about 20secs, does this everytime. It was running fine, but over a week or so, the idle got lower and lower until it would cut out, and it starter a gentle surge'in on the open road, so I changed to my back up carb, it then ran swell for one day, now its started to do the same as before, but much worse. I'm 99% sure its carb related, as all the electrics check out A O KAY. Quote Link to comment Share on other sites More sharing options...
Poo Posted September 7, 2011 Share Posted September 7, 2011 is the fuel filter, pump and airfilter in good nick? Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 is the fuel filter, pump and airfilter in good nick? I took the filter out to make sure it wasnt that, and the air filter is brand spanks, pump seems to be pumping sweet, it runs ok at speed/when flooring it. Quote Link to comment Share on other sites More sharing options...
Beaver Posted September 7, 2011 Share Posted September 7, 2011 so two carbs do the same problem? Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 Kinda, second carb is worse, but worked fine for a day and a bit after I put it on. Quote Link to comment Share on other sites More sharing options...
Beaver Posted September 7, 2011 Share Posted September 7, 2011 maybe leak in the intake manifold? Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 7, 2011 Share Posted September 7, 2011 When did you last replace points and condensor? Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 Yeh, air leak was my first thought because of the surge, but I cant find one, and that shouldnt cause it to not idle? Mr KK, I have not replaced them, but they both seem to be working spot on/everything checks out ok/they look brand spanks. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 7, 2011 Share Posted September 7, 2011 Replace them mate - symptoms sound to me like a shitty condensor.. (they should always be replaced as a pair and they shouldn't cost more than $30 to buy) Also get J5 to install while yelling instructions to him through a large road cone - I find its an effective motivator to get it right the first time. Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 Rodger! Will do sir. I'll also clean out the original carb and slap that back on. Hope it makes it to Tauranga and back tonight, puhuhuhuhu. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted September 7, 2011 Share Posted September 7, 2011 Text me if it doesn't and you get stranded/need a tow.. I'll send you back a text LOL. Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 Haha, cheers boss, I look forward to said text. Quote Link to comment Share on other sites More sharing options...
BlownCorona Posted September 7, 2011 Share Posted September 7, 2011 when i had a vac leak in my r series carb it wouldnt idle right. Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 7, 2011 Share Posted September 7, 2011 Yea do that spark system first, get it tip top. Then make sure you dont have any vacuum leaks, then hit that carb Get a kit for it before you do, as there's a high chance it will be due for a needle, accelerator pump and chances are the gaskets wont come apart well. Also check out the primary throttle shaft, 99% of old carbs are worn out in the throttle shaft bushes Also soak it real good in carb cleaner over night and blow every passage out with air after, use tight fitting screw drivers (grind them down if you have to) or you will fuck a jet/something Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 Yeh, I'll get stuck into it this weekend, cos its a CUNT to drive at the mo. Mind you, just went to tga and back sweet as (apart from not idling) the surging seems to have stopped for the time being. Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 7, 2011 Share Posted September 7, 2011 Yea but kit that carb and chuck some points at it anyway Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 7, 2011 Author Share Posted September 7, 2011 Will do, hopefully it will keep it happy for 6 months, then BAM, v8 time. Quote Link to comment Share on other sites More sharing options...
Spencer Posted September 7, 2011 Share Posted September 7, 2011 It will run like never before if you rebuild that carb properly and get the spark system lush. Quote Link to comment Share on other sites More sharing options...
Vintage Grumble Posted September 10, 2011 Author Share Posted September 10, 2011 Ok, rebuilt the carb, fitted it, still runs like shit. Fit new points + condensor, still runs like shit, re-check fuel flow/timing/dizzy weights/make sure theres good spark and check plugs, still runs like shit. Go to father inlaws and check compression: 20 170 50 170 Mother fucker. Go home, reset the tappet clearances, two valves have no clearance even with the adjuster backed rite off tho, start it up, sounds like a fucked diesel but runs/idles sweet as, just a bit gutless. Just waiting for someone to come round so I can recheck comp. Fucked if im taking the head off, it can stay as is regardless of compression TBH. I'm guessing the two bung valves have suffered "valve seat recession" ?? Quote Link to comment Share on other sites More sharing options...
Beaver Posted September 10, 2011 Share Posted September 10, 2011 lol. should have suggested that, my avenger did the exact same thing, idles like a bag and missfired at constant revs. turned out one of the valves was way to tight and not shutting properly etc. Quote Link to comment Share on other sites More sharing options...
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