Daytona 1200 Jet kit?

[Ketchmi]

I have my 96' D12 in for a tuneup/valve adjustment getting ready for spring and had my mechanic check out the carbs for the "holy" jet kit. It is stock, my question is what will the Dynojet kit give me performance wise? I have Micron cans but it is stock other than that. I do live @ 4400' elevation but travel down to about 2000' sometimes. Jet it for 3k' and live with it?

Also, is the K&N worth it? I use them extensively on other toys, just wondering if they helped the D12 any at all. I know stock filters flow well but I would like to get every little thing I can out of this performance wise.

Thanks,

Dave

[JohnD]

Ketchmi,

I just picked up my D12 from my dealer yesterday after the 6,000 mile service (actually have 5,600 miles on it). The major maintenance at this time is valve adjustment. I had a number of other things done like antifreeze, new brake fluid, fuel filters, etc.

My main issue before this work was that I was experiencing a loss of power almost like I was running on three cylinders. I thought it might be the ignition coils, but I changed coils myself without effect.

Now to some history that might interest you. When I bought this bike over 3 three years ago with 828 miles I immediately had a Dynojet jet kit and K&N filter installed and the stock mufflers debaffled and replacced with fiberglass.

This past week the mechanic zeroed in on two areas for my lack of power. First, one of the valves in cylinder 1 was sticking and it turned out that was the only one that had to be shimmed when the valves were adjusted.

Secondly, while the carbs were running properlly at idle, when throttled up they would start to run lean (the mechanic had the engine on his analyzer machine to read carbon monoxide (CO) and hydorcarbon (HC) levels). The problem was the carbs were not getting enough gas when throttled up.

At this time the carbs were disassembled, cleaned and rebuilt with new seals, and o-rings. A set of Mikuni jets were ordered from a parts house in California. After receiving same a week later the mechanic ended up installing:
115 mains
42.5 pilots

He said that the Dynojet kit that had been installed before had 116 mains, but that he was getting more fuel delivery with the Mikuni 115mains.

I have only ridden it the 25 miles back to my home last night. However, the engine is running very well and I have all the power and maybe more than I ever had. There is no hesitation in the higher gears when I roll on the throttle hard whereas in its best day previous there would be a slight hesitation before the power came on. So throttle response seems better, power delivery slightly faster.

I do not pretend to be an expert. Maybe every bike responds a little differently to carb changes, but I now think that one might be better off with the Mikuni jets rather than Dynojets.

As for the K&N filter, I never rode with the stock air filter so I can't evaluate the difference.

Hope this helps.

P.S. I am about 75 feet (23m) above sea level

[KitNYC]

Personally, I can't stand K&N filters or Dynojet kits.

K&N filters are oiled cotton gauze. They let all kinds of crap into intakes in the name of flowing more air at the beginning, then quickly clog up and flow less air than stock. The oiled foam factory filters have much more linear flow over time and do a much, much better job of actually filtering the incoming air.

As for the Dynojet kits, they use their own numbering system so you can't just look at the number and go buy Mikuni or Keihin jets. If you ask around on here, though, you can find out what OEM jets people are running and save yourself a bundle versus a Dynojet kit. Mikuni jets are $4-5 each... (And I might be inclined to feel differently if I had read about a lot of bikes that run great after a Dynojet "upgrade," but most of what I've read over the years has been more like "I installed my new Dynojet kit and now I have no low end or midrange. I think I have more top end, but I'm not really sure because my bike stalls before I get there.") (Yes, I'm exaggerating. No, not by a whole lot.)

Cheers,
-Kit

[Flying Custard]

Slinging a bunch of jets and bits out of a box and hoping the engine will carburate properly, is a bit optimistic but exactly what a lot of DJ kit buyers do... apart from which some of their kits seem to be, or were, less than fully developed. Best thing is a session on the dyno, going by exhaust gas alone doesn't tell you much of anything. You want to see power and torque curves under different speeds/loads etc etc.

Kehin used a simple numbering system (not sure if still do), where a 130 jet was 1.30mm. So if you wanted a 1.32 you could hog it out and know where you were. There's Mikuni-Kehin size charts kicking around, for what they're worth.

Back to OP, if the exhaust is much different to stock (free-er) then some rejet may well help. Things are more sensitive to inlet side changes than exh side though.
Over here at least our bikes sometimes had a "hole" in the midrange because of noise regs; DJ kits were supposed to fix that. Other kit stages made for further mods like inlet+exhaust etc.

[Ketchmi]

Actually the kit I am referring to is the one from 6sigmaengineering.

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT

My D12 has always idled well but runs pretty rich at mid throttle at this altitude (4400'). At 2000' elevation I probably gained over 10% horsepower whereas I only should have gained a little over 7% from the altitude change so I do know that proper jetting is required.

And Kit, no offence intended but I have sold and used over 1000 K&N filters and I have found that if you are smarter than the filter, they tend to work very well. If you let them get dirty and clogged up of course they will flow less...so will a foam or paper filter. If that means pulling and cleaning them more often than a factory filter, no big deal since you are not buying another one each time. As far as hot wire MAF problems, DON'T DROWN THEM IN OIL! Every vehicle I use them on, I buy a pair. I have one clean & ready to swap in at any convenience then can take my time cleaning and properly oiling the other for the next time.

I encounter so many anti-K&N people it's funny but just how many of them can say that they have actually personally seen engine problems caused by the filter and of those, how many were using the filter like it was actually intended? I will admit that most DIY'ers think that because it is labeled as a lifetime filter that they can just install it and forget it. Sealing the filter to the airbox is also important, I have encountered some true idiots that thought the leaves & rocks in the bottom of their airbox must have come through the filter itself...

You may be an exception but over 98% of the anti-K&N people I have encountered got all their information at least second-hand via the internet or word of mouth. I use them on $30k Porsche engines every day for the track and the street and have never had any problems with them while being used properly.

Rant off, you can now return to your normal programming.

[KitNYC]

They pass more air because they filter less. It's like this:

•Velocity stacks: pass most air, don't filter at all

•Cotton gauze: pass lots of air, barely filter at all

•Foam: somewhat restrictive, very effective filtering

•Paper: most restrictive, most effective filtering

Additionally, cotton gauze filters tend to clog more quickly than foam, at which point they rapidly become very restrictive. That, to me anyway, makes them the worst of both worlds.

And I've never personally seen proof of lots of things, but I'm still pretty sure atomic bombs work and that men walked on the moon. I don't need to see a seized motor to understand that the grit the wind blows into every nook & cranny on my street might do bad things inside a motor at 10k RPM. Letting bigger hunks of crap into your intakes seems like a bad idea to me. If you think it's okay, go for it! Same goes for blowing $100 on $20 worth of jets.

Also, how do you keep track of these percentages of anti-K&N people?

Cheers,
-Kit

[Ketchmi]

You have a trade off in any system, more air vs. cleaner air. I am sure your engine would love to run in a clean room but since that's not realistic you will have to allow normal air in. Nicom/Nicasil is some really tough stuff, I use it on Porsche's that use high boost for it's strength and oil retension. If we were talking alusil, then it's a different story. The cylinder walls are very soft and will not tolerate much abrasion before galling. I still use K&N's (properly) on alusil cylinders.

You are correct about K&N's allowing in more grit due to their design but what is the allowable limit? You might find that the K&N's are clean enough to keep any engine running fine with proper use. Your points are valid but to what extent? It's not a perfect world and you can't have your clean air and lots of it too. (joke!) I am usually running up against size restrictions that won't allow me to run a large enough/clean enough air filter to not restrict my engines. I have 760hp street daily drivers out there, what size paper filter do you think I'd have to run? More than the frontal area of most Porsche's. (think 1600cfm!)

Oh, btw, I co-own a little company that builds Porsche's and race cars and I do retail K&N's as well as use them. That's how I keep track, this conversation comes up frequently. In my humble opinion, people that preach strong likes/dislikes without having firsthand proof are usually the same people that tell me how to build engines even though they haven't actually built one themselves. (I have a shopboy that tries to "help" me with new ideas but can't keep his own POS's running long enough to reliably get to work. He's good with a broom though!) For me it's all about what I know works and doesn't work. If you go by data alone, hummingbirds all over the world would drop right out of the sky. They don't know that they are not supposed to be able to fly.

I also know that nuclear weapons work, I used to maintain them and have first hand proof. As far as the moon... never been there, wouldn't bet my life on it.

[KitNYC]

Sounds like you know exactly what you're doing then. Best of luck with it.

[Ketchmi]

I really do believe it all boils down to personal preference, I was just suprised that someone that holds such a respected profile would allow his personal bias to influence the unknowing. Once again, no offence intended, I was just trying to offer an experienced objective opinion.

Should we ever get the chance to meet, the beer is on me.

Dave

[trypcil]

The kit won't do much of anything a needle shim, fuel screw tweak and careful selection of new mains couldn't. Save yourself some money and spend it going to a good race tuner, though fcrs are about the only thing's that'll unleash the ponies. Being modular bikes, makes you wonder at the varying jet sizes across the range at this time. Cams etc... sure affect the plan but why 115 or less in the Daytona? - the Cal Sprint(3) is 105 stock with tiger cam, Speed 3 is 125+. If the volume of the pump stays the same why the massive variances in fuel delivery? Anyway find a good tuner, usually they're not at dealers. Plus something that is perfect via the 'Sniffer', doesn't mean it'll ride right for your style! - You might like it richer in the mid range than stoic... CV's are mushey anyway, no sense of connect!imnsho