Jetting issue on my 95'

I picked up a Dyno Jet Stage 1 kit and K&N filter and finally got around to installing them yesterday. The bike has 24K miles on her and a 2Bros slip on. She now runs ok/stock below 5k RPM and definitely flattens out above 5k and mildly skips. The plugs were in good shape yesterday. I'm going to pull them to see what they tell me now. I was just wondering if anyone has had similar issues and what resolved the issue. I redrilled the inserts per the instructions w/ the included bit, set the e clip to the third from top and replaced stock main jet w/ 124s. I DID turn out the fule mix 2 1/2 turns per mechanic that I tt midway through mod. The Dyno Jet instructions only said 2 full turns.

If I'm not able to easily resolve, I think I'm going back to stock, maybe even w/ a stock filter as well. Sounds like the JB Weld will work to restore inserts to stock. I am really regrettting this move so far.

Any thoughts would be appreciated!
Thanks
Mark

 

I'm running a Two Brothers Racing Slip-on and a K&N filter and stock jetting right now, and my bike pulls like a maniac above 5k.

My only issue now is with popping and snapping on decel (bike has been de-PAIRed). At first I thought it was kind of cool, but now it's just annoying. I also have a slight surging when holding a constant speed (barely noticeable) that I am attributing to one carb slightly out of sync.

 

Maybe one or more vaccum diaphrams not seated properly would be my guess....nothin to do with mixture screws.

 

Wow. I was super careful putting them back in place. A mechanic I tt said I would prob have to do multiple "cycles" and read the plugs each time and make ONE change. I'm not "feeling" that. If I can't find out what's not right, I'd just as soon go back to stock though might leave the K$N per VT Viffer. I get a lil popping on decel w/ only the slip on. I like it

I guess I'll pull the carbs out again and check the diaphrams. If they look like they were seated ok, think I'll just JBWeld the inserts and re drill to OEM and re install old needles but, I'll leave the new springs in place. I want my old Viffer BACK!

Thanks, guys!

 

UPDATE: I installed 2 new rear plugs and did a plug chop which confirmed how lean she was running. With a week long trip in FL coming up, I wussed out and just re-installed the stock jets (which look painfully similar to the 124 DJs) and needles. I opted to forgo JB Weld on the enlarged sleeve holes just to see how it would match up with the K&N. I set the mixture screws at 2.5 which is pretty much where they were w/ the stock set up.

The Results: Fan Friggin Tastic! As VT Vifffer noted, it pulls like a BEAST above 5500. It's almost like a mini turbo boost. It did NOT do that before. In fact, I thought she was kinda lean in the 5-7k range and avoided it. Now, I don't want to leave that range (lower gears). Its incredible. I also noted my valves were fairly gunked up so, I did my first Sea Foam treatment w/ a full tank of 91. I'm probably going to get about 30 mpg on this tank cause I'm having so much fun. Its like a new bike! The DJ kit might end up being the best mod I almost did.

Of course, I did a thorough cleaning of the carbs while I had them out and installed 2 new plugs up front as well. Really wasnt as bad as I was expecting. Yanking the 14mm and losening the 8 mm (I think) on the left side, allowed me to slide the radi off the right side and managed to squirrel out enough room to get er done. I DID have to do the old coat hanger D&C to extract my socket from the head but, other than that, it was cake. It's been almost 20k since the last change so, figured she was due. even though the plugs looked great (pre DJ). I went with the Iridiums again ($28 shipped from Fleabay).

Fuel filter, brake & clutch fluids, flush n fill, were also performed. I upgraded the horn to something a lil more fierce and just ordered some Sonic springs and SS lines just so I can swap the fluids again?! So much for proper planning. I grabbed an undertail fender (as my tail was already chopped) and grabbed a Zero gravity windscreen to complete the upgrades pre FL.

I have a pretty good rear wheel hop under heavy braking and am looking to do a rebuild via Jamie upon my return from FL.

Thanks!
Mark

 

Dyno jet needles are known to not work right. When you said drill inserts did you mean the slides???
Did you just drill the existing hole larger? Hope you did not drill a new hole in each slide.
If the bike flattens out at top end it just means it is still too lean.
The bike idle ONLY is affected by the pilot air screw up to 1/4 throttle.

Does it backfire or pop on acceleration of the throttle.
I would turn the pilot air screws back to 2-1/4 instead of 2-1/2

When you drill the slide holes larger all that does is make the slides drop quicker for a crisp clean throttle shut off instead of the slide falling slowly.

 

Popping on deceleration is a TOO LEAN condition.
When you have modified intake and modified free flowing exhaust, you have to run a larger main jet. Otherwise it will be lean.
If you modify ONLY the exhaust but NOT the intake you can get away with stock mains .

 

Yes, the SLIDES, sorry. I made them slightly larger (2.17mm).
It no longer flattens out in mid range; she runs great.

It does some mild popping at times on DEceleration...same as it did w/ just the TBR slip on.

I'm in no hurry to take those carbs off again BUT, what size and brand jet do you recommend? Also, will that be plug n play or something I'll have to adjust? I have a trip in 1.5 wks and need her to be straight.
Thanks

 

I used to use iridium plugs./my cost was 10 bux a plug. Really the only reason to use them now is because the damn manufacturers make getting to the plugs so difficult, the iridiums go longer intervals. My VFR is easy to access so I recently went to the stock Honda plug. CR9 or something. Btw my bike has stock jetting/stock pipe/and K&N./fuel mixture screws turned out 2 turns or so. I have the Pair valves still in place too. No back fires on decel and tip of can is nice no black or crap. Gud LuK

 

the best thing to do w/ idle adustment screws is to adjust them for your bike not just leave them at 2 - 2 1/2 turns out.
with bike running adjust them untill idle picks up ( 1/4 turn each one at a time )then turn them untill the idle lowers. you want to be in the middle of these to points so remember how much you turned them in and out.
popping sounds like a tad to lean you should be able to fix that w/ adjusting the needle a bit. if the next slot on sirclip is too much find a shim half of the distance.

 

I agree with that info O2 VFR Rider .
Those screws you refer to are NOT idle screws however, they are slow mixture screws.
Popping on decel IS the mixture screws not the needles. Take them out to 2-3/4 if you have to.

From 0-1/4 turn throttle is mixture screws.

 

My idle is good right now. Should I try turning (open) the screws a bit more or consider larger mains? If larger mains, what brand and size do you suggest?
Thanks
Mark

 

You say idle is ok. does that mean no popping on decel while parked? And no hesitation from idle?
If you modified the intake for better breathing and you added aftermarket free flowing exhausts you will usually have to increase the main jet size.
You might also go one step up on the idle JETS too. You will know right away if you go up one step on the idle jets and turn the air pilot screws down a little if it worked because if they are too big you will get back fires at idle. but it is worth trying because in the summer if the idle is too lean the engine can get too hot.
Better too rich than too lean.
To know about increasing the MAIN JETS ride the bike and at freeway speed accelerate. If it flattens out it needs bigger mains. If it just keeps pulling they are ok.

BTW the needle on the slide goes into the center of the mainjet, so when you increase the mains then the midrange is richened up too.
Usually the midrange is the hardest to set up but changing needles is something you want to stay away from if at all possible. It gets complicated then.

 

Wow, this is gettin kinda sticky. I will check the idle accel/decel shortly but, I thought it was fine. It was only while downshifting to 2nd/1st that i'd notice some popping...not much. I don't think there's any hesitation from idle at all. And my mid range is great...DEF no flattening there. I'm just concerned becasue I'm taking it to Miami in 13 days for a week of riding. It will def be hot down there. If it checks out at idle and is not flattening out at speed - anything else I can check? The only symptom seems to be mild popping at decel. Again, it did that w/ just the 2Bros slip on, too!??!?

 

With the stock jetting...I've usually found Honda's (in general) to be a bit leanish at low RPM and plenty rich on WOT. All things considered...gas milage, good performance, good reliability...I've found stock jetting to work pretty well with slip on exhaust. I usually end up around 3 to 3.5 turns out on mixture screws...helps with decel popping quite a bit, better idle (when this is done usually you end up turning idle knob down for proper idle RPM), quicker decent running on cold start...and oddly enough...more than one customer has told me their fuel milage has improved. I attribute this to being able to run without the choke quicker and because throttle openings are slightly lower at slower speeds because the slightly richer mixture allows the slow circuit to be more effective and useful. On rare occasions I've found shimming the stock needles with one 3mm plane washer (thickness around .020 to .030 inches) has improved bikes with sluggish midrange, or a feeling that the bike is surging at cruising speeds...In one case of a 650 Hawk I went with two shims instead of one because the customer liked it better that way...I thought it was better with one. Anytime you start manipulating the slide needles with shims or replacing with needles from jet kits your fuel milage will probably drop noticably.

 

You are almost there don't give up.
And just like other websites for other bikes, once you have the right combo then every member can rejet with those exhausts and intake with the info you have to share. And if any members here already tried a larger idle jet with those same exhaust and intake and you are reading this please tell us your experience.
When I had my Kawasaki 1500 the owners group shared their information and made my life very easy. Then I shared my information i learned with them.

The brand of jet is not an issue. The jets are only made by a couple companies but sold many places.
Like I said I would go up ONE step on the idle jet and see how it works. That is good insurance from overheating.
They do make mixture instruments for the mixture or you can have the bike put on a dyno and that will tell you a lot too.
When I say ONE STEP on jetting for the idle I mean that if it a has say.. a #38 idle jet go to a #40.
If it has a #145 MAIN go to a #150. Then ride it for a couple days and see if it is better.

On my /kawasaki 1500 V twin with a simple unrestricted intake and aftermarket exhaust
I went from a #65 idle jet to a #70 and #140 main to a 165 main jet.
But even different after market exhausts have different amounts of restriction.
stock needle.

 

I think my mains are 128s, no clue on the pilots. So, I guess a 130 would be one step up. I can call my local garage - guy gave me a good heads up when I told him I was attempting the DJ Stage 1, "you know it's not going to be right, right"? He was right.

So, hopefully he can hook me up w/ a good set up. I'll be sure to share anything I learn, no worries.
Thanks all.

 

It sure seems like some one else would have done this modification. The DYNO people MUST know. IT will not hurt to ask.
When you buy a dyno jet kit one of the things you get is a coupon worth $100 bucks towards a dyno run.

 

Sorry, forgot to reply.

It sounds like we are in agreement that I have a slight lean issue w/ mild popping. All else is good. You say shim my (stock) needles but others think I might need larger mains and possibly pilots.

I'm going to definitely use your method on the screw adjustment and see what/how much that helps first.

Thanks 02!

 

correct, been so long since I have seen a carb.
I should have been a bit clearer on adjusting the slow mix screws first.
thanks