I just did the HRC card wiresplice and the bikes starts. I want to properly jet the bike for a drilled airbox and aftermarket exhaust with the HRC card. I ordered the HRC jet kit and the jet numbers are nothing like the numbers on the stock/installed jets. The jets in the bike now are 55's maybe 155's hard to tell. The jets recommended by someone on this forum awhile back were 192's. The jets in the kit are numbered 1920 (99101-3931920). The other jets in the kit are likewise numbered. Do I just drop the last digit and a 1920 is a 192? Does anyone have any advice for a conservative baseline setting for a bike run in So. Cal. around sea level setup as described above. I also want to use the HRC "B" needles. What is the best way to change these. I got the air solenoid Y fitting but not the X fitting. Has anyone run the HRC kit and if so do I need to change the solenoid jets if I use the Y fitting or should I leave it alone as I don't have the HRC X fitting. Any other advice will be greatly appreciated. I know it's impossible to say exactly what jets I need but a similar MC28 should be close. Thanks,

Steve
1995 MC28
1995 TZ250
2001 R1

First things first; go read the Tuning Section.

It's not the definitive be-all and end-all, but it answers most of your questions, and it's there for that exact reason!
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Andy.
NSR-WORLD.COM

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Andy,

Somehow I missed the Carb info in the tune up section, thanks. As much as it helped I still have a few questions......any takers? If the jet settings in the tune up section are for open airbox and no injector pump what would be a good baseline with a drilled airbox and using the injector pump. Does anyone know what the screw head type is called for the carb top plate, it looks like a torks head with a pin in the middle. I have a set of torks drivers but they don't have the hole to accomodate the pin, know of a source for the tool. The emulsion tube part number in the tune up section doesn't match my HRC kit number is the part number listed for an MC21? Do the carbs on the MC28 have the power jets, I don't see the alloy screw as described in the tune up section. Are there any MC28 owners out there who jetted their owm bikes and can offer some guidance here. Thanks,

Steve
1995 MC28
1995 TZ250
2001 R1

Cant help you with your jetting ,But the screws in the top of the carbs are what we in the trade call 'TAMPER PROOF TORX' these are available in the UK from most motorist shops (auto factors) or tool suppliers .I do know for a fact they are available through SNAP ON TOOLS at about £4.50 a BIT in the U.K .
I think the size of the screw is a T20 but it could be a T15 i cant 100% remember.
I hope this helps BOSOZOKU.
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MC21R Repsol replica
SC36 'Fire storm'
RG250 MK3 GAMMA 'WALTER WOLF'
DR350SEV winter hack

1; yes just drop the zero for the main jet size, standard jets for the 28 are 140's with 75/80 powerjets, they aren't 55's thats for sure if it ran nicely ever.
2; 190/192 is a couple of sizes too rich on mine in summer (HRC card, Tyga pipes, drilled airbox, the UK) draw your own conclusions.
3; the best way to change the needles is to take the whole needle carrier out, yes it does appear you have to mess up the carb balance and no I don't have a good way to get it spot on again to be totally honest.
4; Don't know where the powerjets were located is the easy answer, I didn't fit the jet kit originally and the jetting was a mess when I got it, the '28 does run power jets though.
5; There doesn't appear to be a different x piece on mine, it looks like a std black one and it's "open end" is still blocked with the cap, there are 2 more (presumably) spare caps it the jet kit as well. It is running the HRC Y piece, you can mess about with X and Y pieces and their jets for the rest of eternity if you want.

Really as a base all your after doing is ditching the powerjets (and hence running a lot bigger mains) and fitting the adjustable needles.
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Please do not PM me technical questions, if you can't find it on the Forum start a thread

Thanks guys,
I found the non-tamper torx and will tackle the needles tomorrow. I just need to find the power jets. This forum and the knowledge base from the members is invaluble to new owner do-it-yourselfers.

Steve
Redondo Beach, CA
1995 MC28
1995 TZ250
2001 R1

You dont need to remove the tamper-resitant bolts to install the jet kit.
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Paul Herr
'88 FZR4/GSXR/YZF Frankenbike
MY BIKE PICS

I got the bike back together and took it for about a 100 mile ride today (sunny and 75 here in socal). Derestricting the bike and using the HRC card with the HRC jet kit has completely transformed the bike. It is running much crisper and once on the pipe it screams. It feels almost as strong as my TZ considering the weight difference. It's obviously not making as much power but it feels that much better than b4. I will fine tune the jetting but right now it's running 175 mj's, 42 sj's and the HRC "b" needles in the middle groove. Thanks to those who took the time to post replies to my original post. Now that I've compared apples to apples I will regear as it is way too short now.

Steve
1995 MC28sp
1995 TZ250
2001 R1

I'm surprised you have gone so large on the slow jets. Are you still running the oil pump?

Did you find the power jets? Did you blank them or are they still in place? I'm not going to get into the "wow, 172 mains, are you sure it's not running... (insert rich/lean here!!)" arena, but I am interested to know what exactly you have done!
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Andy.
NSR-WORLD.COM

Please keep all responses to Forum posts on the Forum so that others may benefit.

Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.

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Andy,

It is probably running a bit fat but I wanted to start conservatively to avoid seizing it. I never did find the power jets so I didn't blank them. I plan on fine tuning the jetting on a dyno but my friend is booked for the next three weeks and the weather was too nice today to wait. The sj's that were in there were 42's so I used the 42's from the kit. The mj's were 155's and I went up to 175's now that I'm running the HRC card. It is running far better than before but it will be interesting to see how much better it gets after jetting properly on the dyno.

Steve
1995 MC28sp
1995 TZ250
2001 R1