Can't get jetkit set up right (B12 '98)

[Unruled]

Hi Guys,

I'm new to these boards, been around other places but have come to the conclusion that some more solid knowledge can be found here. I hope you can help me with my new problem...

The thing is I've recently bought Dual K&N fully open filters (look awesome, basically). Thus; I've ripped out the standard airbox (there was really no other way, literally had to pretty much cut the damn thing in half to get it out, is that normal? :P ) which still had the standard filter (in good condition). Now before I did this you should know the bike was running great, it just lacked some proper punch. It already had an open exhaust (Leo Vince SBK) and popped a bit on hard decelleration but that was the only problem.

Anyway, having replaced the airfilter with the K&Ns, everything went crappy, no surprise there, so I bought a Dynojet kit and slotted it in. It immediately was a lot better. After a lot of tinkering around with it I've come to the point where I have a few questions left.

The second carburettor (from the left, rider's perspective) continuously loses it's damn vacuum ring. I place it meticulously, caaaaarefully close the slide cover, ride a few miles and the next time I check the damn ring has just vanished. Audibly noticable too, it leaks even at idle. No surprise then that when this happens I lose all power in the high revs and my top speed is suddenly limited to roughly 80mph. I seem to have this particular problem fixed now, but putting a random piece of rubber in there that's a bit thicker than the standard ring. It no longer leaks and the 'new ring' hasn't yet flown away. New problem: The problem remains At around 70mph now, it just stutters and shudders, but there's no significant 'go'. No matter which gear I'm in, but it's worst in fifth. The silly thing is that full throttle in first effortlessly results in powerwheelies. The power is there, it just seems to disappear at speed...

Aside from that problem, there's the sound. Don't get me wrong, it's awesome, but I'm not sure it's what it's supposed to be. It's not a standard smooth 4-in-line sound, but there's a notable rough edge. Almost as if it's not running nice and round. If this is supposed to sound this way that's quite alright, it sounds cool in the same way that running on 3 cilinders sounds cool, but isn't very helpful in going fast. It does, btw, run on all cilinders. I just have no way of checking how efficiently each cilinder works individually, or is there an easy way to do that?

My last questions is about riding away from standstill. When I do that, obviously you rev to 2.000rpm or so and release the clutch accordingly. The moment I do that it sounds as if my vacuum leak has returned. This particular sound happens at no other point but riding away from standstill (quickly). The sound isn't present when you roll aways slowly.

If anyone of you could answer one or all of the above questions I'd be very grateful. Also, I'd like to know what remedies I could try... I have a GSX-R 750 camshaft (comes from a Bandit 1216, so I'm sure it fits) coming this way, and I'd like to know if I can mount it, or if I should wait and fix this first. Bike uses no oil (for as far as that's relevant info) and none of said problems were present before I changed to the K&N's with a Dynojet kit.

[Red01]

With your jet kit properly dialed in, it should be just as smooth as before.  Since you kept loosing the #2 O-ring, it begs the questions, "Why?" and "Where is it going?"
Seems like something isn't right with how that carb is working and my desktop guess is it is the reason you're having issues. 
  Have you sync'd the carbs since installing the kit?
The DJ kits for the B12 do seem to have more issues for some folks dialing in perfectly than Ivans, Holeshot or Factory-Pro.
With the new cam on the way, you might want to wait until you get it installed and then try dialing it in since it will have an effect.

[Unruled]

Hey,

No I haven't synched the carbs since I placed the kit, could that really be relevant as it ran completely smooth before? I'll run by the dealer to get it done then. I received the cams in the mail yesterday, I'll try and put them in friday, see how that works out :)

[Red01]

Yes, it could be relevant.  Wait until you put the cams in to do it.

[smooth operator]

  I also don't understand how you could loose the O-ring? While your waiting for your cams, maybe get 4 new o-rings (can't be much) and change out the srews on the bottom of the carbs to allen bolts.
  With the K&N pods,full ehaust,cams,timing addvancer, I was running 150 mains. That was what was recomended but I dropped doew to 147.5 mains. I pretty sure I have 32 piolots in, but I'd have to check to make sure, seems like I had tried 27.5s befor and was popping) (I should have notes somewhere) I have my holeshot needles on the 2nd knotch from the top, but I can go as far down as 1.5 from the top using the top clip and 4 washers to go 1/2 clips. The farther down the needles the better fuel mileage you'll get.(check and measure the washers till you get them all the same) Its easiest to adjust the screws in the front of the carbs on the bottom while you have them out. I'm at 2 3/4 turns out. There are many at 3 turns out,but that seems to be where mine wants to be. Don't bottom them down too hard, just till they touch and don't boogger up those screws.  Hope this helps ,Dan

[Unruled]

I have no idea how I keep losing the damn o-rings either, they just disappear :P I've now got a smaller but 'fatter' ring in there, that seems to stay seated... The philips heads under the float covers have already been replaced with allen bolts, big improvement :P

I've now got 155 main jets, needles in de second ring from the top, no extra spacers or anything. I've borrowed a carbtune from a friend of mine, so I'm now going to sync the carbs (if I figure out how that works, but apparently it's peanuts). I'll try turning the mixture screws out a bit, I've got them at 2 full rotations out right now, didn't quite feel right indeed.

Oh yeah, I recently received the camshafts, and as per recommendation only bolted the intake shaft in, and left the outtake standard. Would you recommend replacing that one too? I've heard it means losing the mid-range, and don't really want to lose that. I'll also have to apply a helicoil to one of the cilinderhead cover bolts, which is screwed up, so I'll do that while I've got the tank off anyway. I did already readjust the valves, never ran smoother.


Oh, before I forget... A friend of mine has a B12 aswell (126hp at the rear wheel by dynojet and K&N's), but his will lift the front wheel at 7.000rpm in second gear... Mine doesn't do that. It'll lift, but only with the clutch. He does have a different chain ratio than I do, 1 tooth less at the front sprocket and 1 more at the rear. Could that make so much difference or is mine just down on power?

[smooth operator]

Most of the Banditos only switch the intake to keep the mid range. I switched both on mine, I was doing track days with it untill I picked up the SV1K.
  I'm not sure what mine would read out on a dyno. It won't come up with just a twist of the wrist in 2nd like it does in 1st. A little hump in the road in any gear will bring it up under power. Mine may still not be spot on all through the ranges. I'd like to put it on a dyno w/ the sniffer to see where its at from bottom to top. I've had the carbs in & out so many times, I just stopped when it felt smooth all the way through  w/o any hesitation. Its been a few years since I maessed with it. I had the carbs off during the winter, but it was just cleaning and lubing.

[Unruled]

Yeah, mine will come up on a bump, just not on power alone like my friend's :P Suppose we should switch bikes sometime to compare.

I installed the helicoil (no more leakage :P ) and synchronised the carbs. One was indeed out of tune, but it wasn't the one that kept popping the ring? Seen from the riders position:

1st: Left, left-middle and right were synched, the right middle one was about 4(whatever the measurement is, I forgot) higher. I set them straight and it does indeed run smoother, didn't think it could make that much difference. I haven't had a chance to ride it yet, but I suppose this could make a difference. Still don't get why the 'left-middle' cilinder kept losing rings though, this fatter one stays seated.

[Unruled]

Just did a short testdrive. It picks up a lot better than it used to. No more funny sounds, just go


One more short set-up question. When I go full throttle from 2.000rpm until the redline, there are some dips starting from 6.000 trough 9.000, and it has a slight delay in picking up in the next gear. I'm running the 155 main jets from Dynojet in combination with a GSX-R Intake shaft, K&N Dual filters and a Leovince open exhaust (stock downpipes). I have 150 jets lying around here... would they be more suitable? I have a trackday next sunday, but I'll be away from wednesday morning until saturday evening, so tonight is the last chance of slight tuning I get to do before the trackday :P It's not horrible right now, but I'd like to have it spot-on :P

Reason I ask is because one of you said you were even using the 147.5 main jets, and that's a lot smaller than what I have right now... Dynojet recommended the 155's for open exhausts, that's why I put those in.

[smooth operator]

   I was still a little rich with the 150s. Take a look at a couple of plugs to see what they look like. I tried 152.5s 150s and now 147.5s. My top end seems to be spot on with them, if I have any tweaking remaining to do it would be in the low rpm. I've went down in the piolots till it was popping from being too lean,then went up untill it stopped. (I think 32.5s) I also only get 100 miles per tank of gas. It sure would be nice to squeeze a few more miles out of her. My 1st try set up with the 152.5s and 40 piolots I was pushing the bike back empty @ 60 miles!

[Unruled]

   I was still a little rich with the 150s. Take a look at a couple of plugs to see what they look like. I tried 152.5s 150s and now 147.5s. My top end seems to be spot on with them, if I have any tweaking remaining to do it would be in the low rpm. I've went down in the piolots till it was popping from being too lean,then went up untill it stopped. (I think 32.5s) I also only get 100 miles per tank of gas. It sure would be nice to squeeze a few more miles out of her. My 1st try set up with the 152.5s and 40 piolots I was pushing the bike back empty @ 60 miles!

Wow, that's ridiculous 

I thought you weren't supposed to touch the pilot jets? I just use the screws to adjust them and my low end is awesome actually. Mileage is well, we use kilometers per liter, but 1:16 should be around 38mpg. I get about 140 miles per tank.

I'll try the smaller main jets tonight, then :)

[smooth operator]

I thought you weren't supposed to touch the pilot jets? I just use the screws to adjust them and my low end is awesome actually. Mileage is well, we use kilometers per liter, but 1:16 should be around 38mpg. I get about 140 miles per tank.

I'll try the smaller main jets tonight, then :)
  I was using a chart from Dale Walker's Holeshot Perf. I also was getting info from BanditsRUS board that used to be up. What I didn't understand is why they would go down in the piolot jets? When I did,it would pop out the exhaust wich is a sign of lean. When I went up it cleared it up. I should probably tinker with it some more and try to squeeze out some more milage.