South West Bikers | Motorcycle Forum

On my old R1 i having been experiencing some issues with pulling away.

I am in first, open in up and all it does is lurch and then die, cough a little and then pick up, all under 3000 rpm. I looked into the symptoms online and spoke to a couple of mechanics and they all said that the pilot screws were allowing too much air into the mix. Further reading through the manuals/youtube guide/various other forums stated that the screws needed to be out 2-2.5 turns from the stop.

Dive into the bike this afternoon, make it down to the carbs, get them out only to find that they were all different, varying from 4 to 7 turns out. Of course one was stuck in place so out with the WD40 and nd the screws back ive wouhey presto it moved.

I have wound the screws back in to 2.5 turns from stop and fired it up, sounds alot more responsive from stationary. Hope to get out and ride it tomorrow. I'm guessing i have reduced the air mix, will this make the ports hotter as they are burning a richer mix or should it all be ok ?
I still consider carb trickery somewhat of a dark art so am treading carefully here.

Have i done the right thing ????????????

RIcher = cooler, Leaner = hotter ;) If getting more fuel you'll be ok, its if you're leaning it off you have a problem ....

Pilot should not make a huge difference in normal running , they are basically for tickover and slow running/pulling off, give it a run and pull the plugs, if they look white then things are weak, but midrange topend are the main jets department

that's a bit useful to know, I'm planning on diving into my carbs this winter and I think I need to check my pilot jets as trundling at low revs can be a bit lurchy and lags a bit, over 3000 or so and it pulls fine. I also have had reports of my bike smelling a bit petrol rich when being followed on ride outs. Its been suggested I drop my needles one ring to lean off the mix. I'd like to get new needles but that will cost a bit seeing as I can't seem to get just needles but have to get carb rebuild kits at £12 a carb. Anyone able to suggest where I might be able to get needles separately?

I find carbs bloody scary as I don't want to ruin a fairly well running bike by cack handed messing about and a little knowledge being dangerous etc. ;) !

TBH carb rebuld kits at £12 i would stay away from , that is to cheap for carb bits ,

I would go for new needles and mains and possibly needle jets, most probably set you back more than £12 each though ,

but people on the RD forum have had problems recently with Keyster kits float needles not sealing is the biggest one

as for gen suppliers try suzuki dealers as some parts maybe exclusive suzuki,
or if you know the numbers on the stuff you need try

http://www.allensperformance.co.uk/ they mikuni and keihin
http://www.motocarb.co.uk/ seem to do just mikuni

badgerKDD wrote:that's a bit useful to know, I'm planning on diving into my carbs this winter and I think I need to check my pilot jets as trundling at low revs can be a bit lurchy and lags a bit, over 3000 or so and it pulls fine. I also have had reports of my bike smelling a bit petrol rich when being followed on ride outs. Its been suggested I drop my needles one ring to lean off the mix. I'd like to get new needles but that will cost a bit seeing as I can't seem to get just needles but have to get carb rebuild kits at £12 a carb. Anyone able to suggest where I might be able to get needles separately?

I find carbs bloody scary as I don't want to ruin a fairly well running bike by cack handed messing about and a little knowledge being dangerous etc. ;) !

Give me shout if you want a hand. Keep an eye out on ebay for a cheap dynojet kit. http://fatfingers.com/" onclick="window.open(this.href);return false; is brilliant for finding bargains.

bike back together, went for a bimble - WHAT A DIFFERENCE !

pulling away, no slipping the clutch or anything, who would have thought a couple of threads would make so much difference. certainly sorted the sub 3000 rpm kangerooing out.

, I've got no excuses now to do mine, come winter ;) ....

Cheers for the links from everyone else, I'll have a browse of those and see what new needles are available, cost etc. When my current financial drain is finished I'll look at saving the cash for a set of good needles!

Thing to remember with pilot screws is to take note where they are - as a rule of thumb, if closer to the motor then turning them out richens the motor (they let fuel through) if they're closer to the air box then unscrewing them weakens the mixture as they are air bleed jets.

If fiddling with these, don't be surprised if you need to tweek your tick over.

graham22 wrote:Thing to remember with pilot screws is to take note where they are - as a rule of thumb, if closer to the motor then turning them out richens the motor (they let fuel through) if they're closer to the air box then unscrewing them weakens the mixture as they are air bleed jets.

If fiddling with these, don't be surprised if you need to tweek your tick over.

I put my 97 Bandit 600 on the Dyno a few days ago, the result being rich right through rev range at around 10:1 air/fuel ratio. The mechanic sent me home to adjust (I fitted DynoJet stage 1 myself) and recommended putting e-clips one groove further up on needles, so needles sit lower. This part was logical, but he then said 1/4 turn anti on each pilot screw to further lean up bottom end. My pilot screws are ENGINE side of carburettor, could he have just got this mixed up or has he got this the right way round?

PS. Setting of for John O'Groats in 2 days so will not be tampering too much, Bike being a little rich shouldn't hurt the bike but it might hurt my wallet a little.

Fuel injection is all I am saying

Pilot screws should make naff all difference to the general economy of a bike - how much time do you actually spend riding between tickover and 2500-3k rpm? I bet the answer (unless you have a Harley, which I know you don't) is pretty much zero ..... lowering the needles in the mid-range will have an impact though. If the bike is that rich throughout the rev range, I'm surprised he didn't suggest dropping a main-jet size too ......

I misread graph, 10:1 was the line from a Dyno test a few months ago before I started fiddling. Currently running 12:1 throughout, main jet size was discussed but he said dropping needles should do the job - I adjusted all that he suggested earlier on (the 1/4 turn anti-clockwise included) and it went like a rocket with good throttle response above 4k, but felt a bit lumpy under and was popping and going a bit also. Think will just do pilots back up as they were, Dyno line was near enough straight so close enough me thinks