Got a 2004 ZR900 which everyone said to ride stock first, so I did (impressive). The only upgrade was adding the 05' primary clutch which has a little heavier weights (82g I believe) + bumped the carb clip a notch to lean it a little (its still impressive).

Got a deal on a Black Magic super single pipe plus the can. Black Magic said take the carb clips back to stock position and run 470 mains, I should have no problems. Granted I can play with the airbox some if its a little too fat but a melt down I cannot afford.

The clutch is the biggest question,,,,,,,I'm wondering how far off I am with the 05' clutch. I already have 82g weigths which should keep the RPM's down in the 7600-7800 range, helix and stock springs are a ???.
Better stated is it worth the excitement or disappointment to get the 249.99 kit from BM racing.?

CALL Dan (b4 U do ANYTHING. You wont be sorry.)
@ http://lencco.com/index.html

ASK about these two items;


http://lencco.com/html/big_twin.html

http://lencco.com/html/clutch_weight_adapter_kit.html

AND if iyou nsist on pipe "magic"..BMP ZR 900 Stock Pipe Mod
...this flat out works.>

http://www.bikemanperformance.com/products...afbe6e0e3cc7edd

i have installed both the pipe and clutch kits on a few sleds. i found the pipe a little tight, worked great out of the hole but missing a little on the top end.
their clutching flat out works, very impressive.

I would think if you run the stock primary setup just add an orange secondary spring and a shift assist, check your rpms and adjust up (yel/grn, yel/white) if needed. We tried a few different helix's on them and the differences weren't real noticeable. The big issue is to be in the working range of the pipe and get it fully shifted out. I usually clutch to the bottom of the torque band and pull up to the top rpm on the end, more weight the better. Depending on elevation and temps, I would guess you'll end up at around the 450-460 range with the shelf out on jets and clip it 4th., start at the recommended jetting and work down based on wash.

Thanks,
Running at 2500ft and typically between 10F-20F in Southwest PA. Tuning time and turning bolts is tough, late seasons and limited snow the last few years - but when the snow flies its time to fly. Looking for some good suggestions without scattering it (or costing me $$). Low to midrange is where its at, no frozen tundra round' these parts. I do still have a few 100+ places to use the top end...!!!! Didn't get chance to pop the carb open yet, 4'th is stock position.?? Maybe start with 460's and leave the shelf in..?

I havent used a BM single but Im sure its similar to the SLP's Ive done, Id say for your elevation and avg temps with the shelf in, you'll prob end up around 450/440. If its colder than usual you might need to jet up. We've been running TPI's so when it gets a little warmer you can open them up and basically drop a jet without wrenching.

I tried one BM pipe. I think they wanted 470 or 480s. I ended up around 430-440, yes back to stock jetting for warmer days above 30 or so. On colder nights (in NY) I would just close up the box so I'd say 450 will be safe for you. This was with an opened airbox and timing, needles clipped on 3 (stock) or even down leaner to 2.5. The pipe was sluggishly fat off th line with 470s and the Needles up to 4 or even 3.5

Thanks,
Obviously personal opinions and experiences do vary. I'm also going with a 2-degree timing when the pipe and can is installed. Overall it sounds like putting the clips back to stock, running 450's or 460's, and checking the wash would be a good starting point. If too fat airbox a good airbox mod is take out the shelf and then.........put the stock lid back on? get a power breather? install a few bullseyes in the top side (tape over below zero)?

Careful with the timing key

BM pipe is definiately too tight for the 900 and DON'T run timing key with this pipe. This pipe was built for the 800, I know the guy who designed it. I ran 2 degree key with BM pipe on my 800 and even with a stagger 480/490 jets I was showing signs of deton.

Timing keys gain about 1-2 horsepower and on the ice the HP gains are not measureable. Not worth the risk with todays crappy fuel.

It's very important that you make sure your crank is within .002 runout as you WILL not gain full potential of this motor. Also tune with digital tach to be exact and MAKE sure you have perfect clutch distance and alignment.

I set up a '03 ZR900 with a Speedwerx single pipe. Speedwerx claims 7600 RPM but we found max speeds at 7350 with 460/470 mains. This sled flat out rips and we do a lot of friendly drag racing plus 1000' runs. It takes a modded Thundercat to beat this sled.

The ZR900 can be fast with stock pipe and trail port. That's what I would do based on my experience with my 8 and a bud's 900. Torque is the key and the stock pipe makes it. Clutch to load the motor at 7200 for 1000' and climb to 7300 after. If you're set on an aftermarket pipe go with SLP or Speedwerx.

FYI I'm sure I'll get slammed for this but my ZR8 carb with stock pipe and trail port, trued and welded crank, Tempaflow, CT reeds I have run 105+ in 1000' right off the trail. Only two F7's have come close to me and one had twin pipes that I set up. The other had Fat Ass pipe, timing key and fuel reducer and was clutched right. He could creep by at the very end. I mentioned this because the stock pipe IMHO is where it's at for the 8 and 9's. If it were me and you can tune a clutch, I'd focus on clutching and gearing with a trail port.

APVZR8

I didn't realize you already had the BM pipe.

Want my personal opinion? Get rid of it and save yourself a big headache.

I ran this pipe on the sled it was designed for (ZR800) for 2 years. Although I don't regret it and won most of my races but when I went back to stock pipe, what a relief!!! Much easier to tune and much better for trail with way better mileage. Also I discovered it's faster with the right set up.

Save yourself the hassle.

APVZR8

"FYI I'm sure I'll get slammed for this but my ZR8 carb with stock pipe and trail port, trued and welded crank, Tempaflow, CT reeds I have run 105+ in 1000' right off the trail. Only two F7's have come close to me and one had twin pipes that I set up. The other had Fat Ass pipe, timing key and fuel reducer and was clutched right. He could creep by at the very end. I mentioned this because the stock pipe IMHO is where it's at for the 8 and 9's. If it were me and you can tune a clutch, I'd focus on clutching and gearing with a trail port."

Sounds pretty good, I'll believe it. Mine (prepped like your sled but I also had the heads done and ran timing) use to be good for 103-104mph on trail studs in 1000' with a 200lb+ rider.

On my 04 before I had the motor done and pipes built. Ipulled the shelf in the airbox with stock jetting. Installed a cpr clutch kit. Made sure the paralellism of the clutches and offset were correct. With it studded for ice it ran 116 on top end and to 100 it was a bear.. I would call and talk to rory at Black Magic and he will set you straight on the pipe deal. I have never added a key so dont know about that i have 4 different ecu's programmed. When adding timing you are changing the way the pipe reacts due to the change in pipe heat.

Thanks,
I did get some information from Rory recently. Seems a little fat but he said with the super single & can use 470 jets, carb clips back to stock, keep the airbox in tact, add the 2.2-degree key, use good fuel not necessarily premium. My clutch has 83g weights which are a few grams heavier than the stock setup. With the stock 50/38 helix & springs (yellow/green primary and white secondary) I likely have some room to improve - Kit is $250. Not ice racing, 210LB rider looking to smoke the trails and be respectable when I line it up.