gs7_11 Posted October 2, 2017 Share Posted October 2, 2017 (edited) Anyone had any experience with fitting a stage 3 Dynojet kit to CV carbs like the Mik BS's? Done a search on the forum but can't find anything specific. I'm putting a set of BS34's on my GS1000, and considering my options about airboxes v. K&Ns. Does the Dynojet kit work properly? i.e. smooth carburation over the whole range. Edited October 3, 2017 by gs7_11 make title more inviting! Quote Link to comment
gs7_11 Posted October 3, 2017 Author Share Posted October 3, 2017 (edited) No-one? I need input! I-n-p-u-t! Edited October 3, 2017 by gs7_11 Quote Link to comment
pigford Posted October 4, 2017 Share Posted October 4, 2017 Got a kit on my ET..... was already fitted & set on a Dyno.... works okay, bit lumpy down low end, but they are CV's with K&N's!!! Apart from Dyna coils and an Eagel 4:1 all standard and makes 99bhp at wheel. 1 Quote Link to comment
gs7_11 Posted October 4, 2017 Author Share Posted October 4, 2017 Thanks for the reply. Hmmm. Lumpiness at the low end is exactly what I don't want. I'd hoped the Dynojet kit would deal with that. I'd be better sticking with plan A then (airbox)...don't mind giving up a few bhp. Quote Link to comment
pigford Posted October 4, 2017 Share Posted October 4, 2017 It may not be the fault of the Dynojet kit? As it was already on the bike (fitted a few years back I believe) who knows what settings were used with it??? The glitch is at slight opening of throttle - it hesitates a bit and seems a tad rich? Other than that its good..... I'm being very picky! 1 Quote Link to comment
wraith Posted October 4, 2017 Share Posted October 4, 2017 It all depends on the whole setup, as the zorst can/will make a difference as well as airbox or k&n filters. 4-1 gives more top end power and a 4-2-1gives more allover power and if you speeck to Dyna themselves they will tell you getting it spot on all the way through the revs with a 4-1 is at best hard to get. 2 Quote Link to comment
arnout Posted October 4, 2017 Share Posted October 4, 2017 21 hours ago, gs7_11 said: No-one? I need input! I-n-p-u-t! Yup.. I once (long time ago) had a "stage 3" Dynojet kit installed in the BST36ss carbs on my GSX750/1170. I think it ran quite well apart from misfiring at the top end (which I later found was caused by using copper instead of suppressor leads with a Dyna2000 ignition). Don't remember whether I was still using the airbox back then or had fitted pods. But these kits are developed for specific bike models. Carb tweaking has already been done by Dynojet. So bolt on and you're in the ballpark carb-wise. So this won't work with non-stock carbs, and the dyno-operator-guy indeed spent a lot of time on getting the settings right on my GSX. On 02/10/2017 at 12:48 PM, gs7_11 said: Does the Dynojet kit work properly? i.e. smooth carburation over the whole range. Well.. It might.. If you put in enough dyno time to get the settings right. An experienced dyno-operator/carb-tweaker may not find any use for Dynojet parts in order make the Mikunis work well though.. 1 Quote Link to comment
johnr Posted October 4, 2017 Share Posted October 4, 2017 (edited) years ago i fitted a dynojet kit to the cv carbs on a gs1000g shafty, the kit made a huge difference to the way the bike rode. i never had it on the dyno so ive no figures to back it up, and theres a huge BUT involved. at the time i was using the gs as our family car with a huge old coachbuilt sidecar attached. so, i never really pasted it at the top end, as we were usually 4 up, me and the mrs on the bike and the kids in the chair. but the hesitancy and lumpyness that the bike had before were now gone completely and it was super smooth and tractable, but i cant really comment for the top quarter of the rev range cos i never went there. sorry i cant help more than that. the bike was stock with an alfa 4 into 1 and a stock airbox with no top in it. it ran ok when i got it, and the lumpiness wasnt really a problem as a solo cos it wasnt often running that slow as a solo. having said that, im not sure you can still get th dynojet kits now. the one i had included a drill bit for opening the holes in the carb slide as well as pilot jets, needles and a selection of various mains and air screws. Edited October 4, 2017 by johnr Quote Link to comment
Dezza Posted October 4, 2017 Share Posted October 4, 2017 Such a shame there is no current equivelent of the Ledar induction kit. So simple but yet so effective. 1 Quote Link to comment
johnr Posted October 4, 2017 Share Posted October 4, 2017 so good you said it twice........ Quote Link to comment
gs7_11 Posted October 5, 2017 Author Share Posted October 5, 2017 16 hours ago, Dezza said: Such a shame there is no current equivelent of the Ledar induction kit. So simple but yet so effective. Yeh, but wasn't the LeDAR kit just for slide carbs? Quote Link to comment
gs7_11 Posted October 5, 2017 Author Share Posted October 5, 2017 (edited) 17 hours ago, arnout said: Yup.. I once (long time ago) had a "stage 3" Dynojet kit installed in the BST36ss carbs on my GSX750/1170. I think it ran quite well apart from misfiring at the top end (which I later found was caused by using copper instead of suppressor leads with a Dyna2000 ignition). Don't remember whether I was still using the airbox back then or had fitted pods. But these kits are developed for specific bike models. Carb tweaking has already been done by Dynojet. So bolt on and you're in the ballpark carb-wise. So this won't work with non-stock carbs, and the dyno-operator-guy indeed spent a lot of time on getting the settings right on my GSX. Well.. It might.. If you put in enough dyno time to get the settings right. An experienced dyno-operator/carb-tweaker may not find any use for Dynojet parts in order make the Mikunis work well though.. Well the description for the Dynojet kit Stage 3 suits my bike (or will if I keep the pod filters) so theoretically the kit should work first time. I also have a vague memory of a magazine article or something where a bike was fitted with a Dynojet(?) kit, then sent to a dyno to be tested. The operator tweaked the kit till it was right, put the standard needle, different main jet and air corrector in, thus leaving nothing of the Dynojet parts! Not exactly a ringing endorsement, so my instinct is to stick with the standard airbox. [ Incidentally, the GS1000G airbox flows better than the GS1000ET airbox....in the case of CV carbs the main jet is 107.5 or the chain drive bike, 115 for the shafty. This was born out when I fitted a stock set of VM28 carbs to my bike, when it had a standard slide carb head, with a GS750/850 airbox (and 1000G rubbers of course) and on the dyno it was lean, ahd to go up a few sizes on the mains at which point the power was up a fair bit. So there you go.] Edited October 5, 2017 by gs7_11 Quote Link to comment
Dezza Posted October 5, 2017 Share Posted October 5, 2017 40 minutes ago, gs7_11 said: Yeh, but wasn't the LeDAR kit just for slide carbs? No, they did them for all carbs. I still have one fitted in the stock carbs on my bike which has an efe engine. It runs well with s and b filters and an unrestrictive exhaust (when I can be arsed to balance the carbs). Apparently it's all in the little brass air corrector jets supplied with the kit. You got a blind tap with the kit and had to tap a thread into the small outlet facing away from the engine on each carb. Then change the main jets and away you go. Might need some alteration with the needles but nothing like all this dynojet kit faffing about, at about 1/3rd the cost of dynojet (when each were sold at the same time). Quote Link to comment
gs7_11 Posted October 5, 2017 Author Share Posted October 5, 2017 3 hours ago, Dezza said: No, they did them for all carbs. I still have one fitted in the stock carbs on my bike which has an efe engine. It runs well with s and b filters and an unrestrictive exhaust (when I can be arsed to balance the carbs). Apparently it's all in the little brass air corrector jets supplied with the kit. You got a blind tap with the kit and had to tap a thread into the small outlet facing away from the engine on each carb. Then change the main jets and away you go. Might need some alteration with the needles but nothing like all this dynojet kit faffing about, at about 1/3rd the cost of dynojet (when each were sold at the same time). Ah, I didn't know they got round to doing them for CV carbs. It's been a while since I've heard of them. Actually, that's pretty much what they Dyno jet kit is too: main jets, air corrector jet, and with the Dyno kit you get a different needle too. Quote Link to comment
arnout Posted October 5, 2017 Share Posted October 5, 2017 5 hours ago, gs7_11 said: ...and with the Dyno kit you get a different needle too. Ah yes.. Forgot about that can of worms.. Be wary of those Dynojet needles..! Because these were (still are?) not finished smoothly they wear down emulsion tubes (needle jets) much faster than normally would be expected. (Worn oval the tubes cause the fuel mixture to become overly rich especially at low revs, which is a familiar issue particularly on the Mikuni BST carb type series having been fitted with Dynojet kits/needles). The fix is simple: gently polish the needles smooth before fitting them. Quote Link to comment
gs7_11 Posted October 6, 2017 Author Share Posted October 6, 2017 20 hours ago, arnout said: Ah yes.. Forgot about that can of worms.. Be wary of those Dynojet needles..! Because these were (still are?) not finished smoothly they wear down emulsion tubes (needle jets) much faster than normally would be expected. (Worn oval the tubes cause the fuel mixture to become overly rich especially at low revs, which is a familiar issue particularly on the Mikuni BST carb type series having been fitted with Dynojet kits/needles). The fix is simple: gently polish the needles smooth before fitting them. Well I've given up on the Dynojet kit idea. Too many meh reviews and my own limited experience. I've fitted a 1000G airbox with totally standard CV carbs. Fits the 750 frame/1000 engine combo perfectly. Smooth pick up, very light throttle and no mahoosive power loss. Bearing in mind I have Kent cams, I thought it might start to feel stifled at the top, but no, haven't felt it yet. Yay Quote Link to comment
pigford Posted October 6, 2017 Share Posted October 6, 2017 All the Dynojet needles had a more aggressive taper to eliminate the midrange "lean spot" to meet emissions regs.... but they were better than standard needles.... Main problem is the CV carbs are shite for tuning! Quote Link to comment
Gixer1460 Posted October 7, 2017 Share Posted October 7, 2017 14 hours ago, pigford said: All the Dynojet needles had a more aggressive taper to eliminate the midrange "lean spot" to meet emissions regs.... but they were better than standard needles.... Main problem is the CV carbs are shite for tuning! Depends what you call 'tuning' ! My 36mm CV's gave plenty of power with a virtual straight line from idle to max - no holes! If you know what you are doing anything can be 'tuned'! BUT they are shite for racing as they only give what the engine wants not what you want to give it - subtle difference! Quote Link to comment
pigford Posted October 7, 2017 Share Posted October 7, 2017 (edited) 9 minutes ago, Gixer1460 said: Depends what you call 'tuning' ! My 36mm CV's gave plenty of power with a virtual straight line from idle to max - no holes! If you know what you are doing anything can be 'tuned'! BUT they are shite for racing as they only give what the engine wants not what you want to give it - subtle difference! True - I was stating from my "basic" experience , ie; not having a dyno in my garage..... old skool; by the seat of your pants, ear/feel tuning. CV's prefer airbox pressure (stable air) to operate at their best. Non-CV like stable air too, but more forgiving. Us "built-in-a-shed" peeps can get faster & better results using non-CV carbs most of the time, but always exceptions. Flatslides/Smooties also look so much better! Edited October 7, 2017 by pigford 1 Quote Link to comment
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