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what is an HRC jet kit, and why do i need one?


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MAINE 2 STROKER

 
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what is an HRC jet kit, and why do i need one?

Mon Nov 29, 2004 8:42 pm » Post: #1 » Download Post

i see a lot of members bikes and the like with the HRC jet kit

what is the difference from this and just going out and buying the carberator manufacturers jets?

i am planning to buy some tyga pipes, and realize the need for jetting changes. Just curious to whats so special about the HRC kit

on my dirtbikes, i just would order a few jet sizes close to what i expected and then take plug readings, etc...

this usualy cost me about 20 - 40 buck depending on how good my guessing was...

I live in maine, so i have to jet a bit rich to make it happy over the varience in temperatures, but im not opposed to haveing 2 sets of jets...
one for early spring and late fall, and then a leaner set for summer.

Any thoughts comments or suggestions appreciated!

Thanks
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Jeff SZ

 
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Tue Nov 30, 2004 12:15 am » Post: #2 » Download Post

Your stock needles are not adjustable, that is the biggest thing. I bought the HRC kit and I used very little of it. All of the main jets are too big for oil pump running NSR's. The only thing I used were the B needles, needle holders, & needle jets. I had to order main jets starting at 150 mains and all around that size from there till I got think good. I'm running Tyga GP pipes with Tyga mod. air box lid, live in Sandown NH. You can get just parts from this guy in US. http://www.redline-ci.com/ He's nice to deal with and he was living in Durham NH untill this summer and moved back to Cali. But still quick delivery from across country. Read the jetting section in the tunning section of this site, it help alot !
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Jeff SZ

 
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Tue Nov 30, 2004 12:20 am » Post: #3 » Download Post

Oh, also running Tyga reed cage, stuffers & carbon fiber reeds.
http://tyga-performance.com/
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Wrench.

 
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Tue Nov 30, 2004 3:28 am » Post: #4 » Download Post

For street use, the kit is pretty useless. It comes with the minimum needed to block off the oil injector, and the jets are much larger than you will need on a bike that is not highly modified.

Key parts that come with it: adjustable needles, and different "X" and "Y" pieces for the air jet system.
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JohnBlaze

 
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Tue Nov 30, 2004 7:27 am » Post: #5 » Download Post

so what do you think Mr. Herr....? is it advisable to block off the powerjet for street use? Ive been contmplating it to get rid of another variable.
BTW...i blew up my front piston again. Twisted Evil
problem is... i dont know why yet.
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MAINE 2 STROKER

 
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so what kit should i be looking to get?

Tue Nov 30, 2004 1:36 pm » Post: #6 » Download Post

so what kit should i be looking to get?
the jha kit, other kits... does NSR world have a kit for sale yet?
or should i just guess, and buy the parts i think i need?

thanks for the advice
the bike is a derestricted street bike and uses the oil injection system
it has carbon reeds already, not sure if it has stock jetting as i havent been in the carbs yet. Has stock pipes, and Seat of the pants HP guess is like 51 or so..
im gonna get the "one on each side" TYGA pipes and cans
im looking for a reliable 60 hp or better with rejetting

would consider other minor mods (airbox or filters anything to extract "free" HP)
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Dave Ett
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Tue Nov 30, 2004 2:32 pm » Post: #7 » Download Post

60 hp shouldn't be hard to find. I was getting 63 with no filter, and I hadn't done that many mods.

Pipes and opening up the airbox will give the biggest single gains, with the rest coming in smalls bits as you perfect the jetting and powervalve alignment.
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Andy
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Tue Nov 30, 2004 3:46 pm » Post: #8 » Download Post

Every application is different, so although you may not need an HRC kit, it is a worthwhile investment, in my opinion. You never know when you are going to drop the oil injection, or when you are going to seize because some debris from the bottom of the tank blocked a tiny power jet (not scare-mongering... I've seen it happen - twice!) and some of the kit just isn't widely available separately.

Sure, you can go and buy a range of mains an a couple of slow jets, and depending on your location spend anything from $50 to $100 (jets aren't cheap here in the UK, but hey, what is?!), but if you then carry out more extensive mods you will find you could use adjustable needles (which warrant HRC holders and HRC emulsion tubes) and maybe the X and Y peices - both of which are not available as separate items, therefore finding yourself with the need to fork out $200 for the kit anyway!!

As Paul rightly says, most of it is not usually required for the street, but there are some who have found it invaluable... there are others I know who don't even run a full kit even though they race!

Horses for courses, but if you can get a kit, buy it I say... it's worth points in the Posers League if nothing else!! :lol:

I looked into producing a kit for NSR-WORLD.COM consisting of the usual basics but it just doesn't really pay. I would advise a Jha kit personally. Not only does it come complete with the X and Y peices, but also PJ blanks (if you want to use them) and a sticker!! Naturally their kit comes with the big mains because it's tailored for those who don't want to use the PJ's.

Andy.
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Wrench.

 
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Tue Nov 30, 2004 4:03 pm » Post: #9 » Download Post

In my quest for power, I have blown alot of money and tried alot of things on my MC28SE. Here is what I came up with:

For street use, keep the injector system. If you are concerned about oil, get the injector-use castor-based oil by Blendzall (available here in the US). Great stuff, and has that wonderful smell. Smile Use all the add-ons listed by Tyga (power-up kits), and the Tyga pipes are seriously tough to beat. And do the front head conversion. This will net you a very fast, but very reliable bike in the 60hp range. To make the bike even quicker, you can lighten the flywheel and remove the kickstart system.

Bumping up the compression higher than stock will make the bike want to run high-octane gas. Especially with the ignition derestriction. Not advisable on a street-going bike.

Modifiying the airbox will change the jetting requirements alot, depending on how far you go. I originally cut the top and installed a Daytona filter. This helped a bit, requiring leaner pilots and richer mains. I later found out that the Daytona filters have a restrictive plastic layer between the two layers of foam. I peeled mine apart, removed the plastic, and used sewing thread around the edges to keep the two foam layers together. Once again, I had to go a tad higher on the mains. I also custom-made some inserts that tapered and enlarged the rubber intake boots (between carbs and airbox) by a large margin. This gave the same power as having the box entirely removed, but keeps the filter in place. It made my jetting requirements jump ALOT on the mains. Power was up at peak, but midrange is a tad softer.

As for the jet kits, they are all pretty much the same. The JHA units are actually just relabled HRC kits. I used an HRC kit once, and had nightmares trying to get it right. Getting the jetting correct for high-rpms would make the lower rpms run too ruch and get a ton of spooge out the pipe. Overall drivability and low-mid power suffered. Am I the only one who has experienced this?? I currently run the stock setup, but have a set of Bakudan adjustable needles I just happened to stumble upon. This seems to work fine, even with my overbore. At least it did before I left Japan. I still dont have the bike registered here, so have had no chance to change the jetting for local conditions. Still looking for ways to get it licensed...
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Andy
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Tue Nov 30, 2004 4:22 pm » Post: #10 » Download Post

I forgot to add that my experiences are more MC21 biased, but found the adjustable needles invaluable when tuning an Eric Gorr ported MC18. I just couldn't get it right with the stock bits.

My '21 runs dry Ramax filters (no airbox) "B" needles, #40 slows, PJ blanks and big mains (no, I'm not giving numbers!). I also run the HRC X and Y pieces, but that's because I haven't been able to try it on a dyno to see the difference in effect it would have not using them! I'm sure the difference is small, but the Poser points are big!! :D

What we need now is Matt Patterson to jump in and throw his cat amongst the chickens and contradict both Paul and myself with another entirely different opinion again! :lol:

Andy.
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Wed Dec 01, 2004 2:38 am » Post: #11 » Download Post

Could some one explain what the X & Y pieces do over stock X & Y ? I installed a kit but did not use them, would I gain anything ?
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JohnBlaze

 
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Wed Dec 01, 2004 4:57 am » Post: #12 » Download Post

i was under the impression that the X and Y pieces are only needed if you wrere running pj blanks. Its supposed to by pass the solenoid that controls them? is that right???? Confused
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JohnBlaze

 
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Fri Dec 03, 2004 7:35 am » Post: #13 » Download Post

anyone got any insight on this? can you run the x and y piece if your still using the PJ? Confused
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Andy
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Fri Dec 03, 2004 10:50 am » Post: #14 » Download Post

Different size jets in the X and Y pieces.

Again, applications vary, and you really need a dyno to tell whether they are helping or not. I can't remember if the jets are larger or smaller than stock to be honest, but they effect mixture pretty much across the entire rev-range.

I would imagine (and it's speculation) that you would be best off with the stock Y piece at least, if you are running the PJ's.

Andy.
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