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Re: Revs Trouble Climbing
Posted: Sun Dec 20, 2009 3:22 pm
by DoktorMandrake
Also... how big should the hole in the pilot jets be? Less than a pinhead? Can't tell if it's fully clear or not. Can see daylight and then sometimes nothing. Guess there's a bit of crab in there somewhere.
Re: Revs Trouble Climbing
Posted: Sun Dec 20, 2009 4:14 pm
by Neosophist
Everything is fully screwed in apart from the pilot screws.
If their loose theres something wrong.
Are you confusing parts?
If you remove the pilot screw you'll find theres a spring / washer and rubber o-ring on the end of it. Don't loose these.
Screw the pilot screws fully in (gently, dont tighten them up, you'll knacker them) and then back them out 2 turns to start with. i've seen some people class half a turn as a full turn before, so if you have any doubts, put a coloured dot on your screwdriver and turn it until the dot is back in the same place for 1 turn, then do it once more.
The main jet unscrews off the emulsion tube, then the emulsion tube can be unscrewed too.
Also take out the pilot jet.
Soak everything in carb cleaner and blast it with compressed air.
Check all your emulsion tubes are in the right order, if you have 2 with more holes in them, they go in the rear carbs.
Make sure everythings clean and put it all back together, check the float heights while you have them in pieces too.
Finally, when re-fitting to the bike make sure they have a good seal around the rubbers and fire her up and fine tune :-) (i.e balance, pilot screws)
Re: Revs Trouble Climbing
Posted: Sun Dec 20, 2009 10:10 pm
by CMSMJ1
You are confusing pilot jet and pilot/air screw mate.
Inside the float boals you have the main jet which screws into the emulsion tube and then an air/pilot jet - prob sized 35 - which is a small hole.
On the body of the carb you have a flat head screw that alters idle circuit - have a look in Viper's thread at his pictures of the carbs - that will sort your head out.
Everything in the flaot bowls that screws in gets screwed in nice and snug - nothing a set turn here or there.
Re: Revs Trouble Climbing
Posted: Sun Dec 20, 2009 11:58 pm
by DoktorMandrake
Yup you're right. So much for skim reading the Haynes. My bad. I was all ready to go on a 'I have taken carbs apart before, y'know' rant

However, I did indeed confuse the two. Oh and as for the emulsion tubes, the reason I was wondering about how many turns out they're set is as some of the threaded section is visible when they're tightened/it doesn't screw in fully. Or rather it does, but some of the threaded section is presumably visible as the tube is designed for a few different carbs. All sorted now though.
It's all back together and tomorrow I shall reassemble and hope for the best. One pilot jet was a bit blocked, several others gummy (they would appear to clear, so I could see light through them but then next minute I couldn't see a lot, so I got them as best as I could as I didn't have anything thin enough to poke through, then set the pilot mix screws to 2.25 turns out) but the emulsion tubes were in the right carbs and none of the holes were blocked, main jets were all fine too. Once I get her running sweet (fingers crossed) will probably have a look at jetting properly using DataRacer's guide.
Thanks for ya input chaps. Deffo appreciated. Will let you know how it all goes when I fire her up tomorrow. Fingers crossed.
Re: Revs Trouble Climbing
Posted: Mon Dec 21, 2009 12:19 am
by Neosophist
2.25 turns might be a bit rich depending on your exhaust system but it's a good basis to start from.
Crank the starter a few times (say for 3 or 4 seconds) then leave the bike for about 5 minutes to allow fuel to drain into the empty carbs.
Full choke no throttle and crank it till she fires.
If you don't allow the few mins for the fuel to drain into the carbs you'll run the battery down :-)
Good look :-)
Re: Revs Trouble Climbing
Posted: Mon Dec 21, 2009 12:57 am
by DoktorMandrake
Thanks for the advice, mate. Will do.
Just have a Scorpion end can on. So should I set the pilot mix screws at 2 turns out then? Don't really want to be faffing about with the pilot mixes if I don't have to. Will be doing it properly for real in the Spring (new jets, needle washer, slide drilled etc.) but for now I just want a bike that runs as sweet as poss with as little effort as poss to get me through winter.
Re: Revs Trouble Climbing
Posted: Tue Jan 05, 2010 11:12 pm
by DoktorMandrake
Neosophist wrote:2.25 turns might be a bit rich depending on your exhaust system but it's a good basis to start from.
Crank the starter a few times (say for 3 or 4 seconds) then leave the bike for about 5 minutes to allow fuel to drain into the empty carbs.
Full choke no throttle and crank it till she fires.
If you don't allow the few mins for the fuel to drain into the carbs you'll run the battery down :-)
Good look :-)
Neo, how come it takes such a long time for the fuel to drain into the empty carbs? I actually slide my gsxr down the road on ice yesterday with your words ringing in my ears. I had been due to take the VFR but unfortunately like a complete plum I forgot to turn her fuel on. So she fired straight up with a bit of choke like a good gal but as I was shutting the garage door she gurgled and started dying. Took me a min to realise why and flicked the fuel on but was too late. So then I did as you mentioned. Cranked the starter and left her but maybe got impatient and ended up flattening the batt so I had to take the otehr bike. Just wondering why it takes so long for the carbs/lines to get fuel back in em?
Re: Revs Trouble Climbing
Posted: Wed Jan 06, 2010 2:53 am
by Cammo
If you still have teh standard fuel tap then no fuel enters the carbs when you turn the tap on (they don't fill up).
Fuel will only enter the carbs when the engine is turning over as engine vacuum opens up the fuel tap diaphram allowing fuel through to the carbs.
If you have no diaphram (hrc tap mod) then fuel flows as soon as you turn the tap to on (or plug it in if you have it disconnected - smarter option by far!).
Re: Revs Trouble Climbing
Posted: Thu Jan 07, 2010 5:10 am
by Neosophist
It's becuase of the vaccumn operated tap.
If you crank it for 5 or 6 seconds then leave it a few mins some fuel will trickle into the cabrs.. this will be enough to fire up the bike, before that bit of fuel runs out more will be coming on the way :D