My '82 XJ750 "Project Shadow Warrior"

this isn't a modification thread but rather "built from scratch" thread! Really awesome project, man! Thumbs up!!!

 

Sickkkkk build!!

Cant wait to see how it ends up looking!

 

i love the monoshock idea and execution but i would be concerned about moving where the force is exerted on the frame, the rather small tubing cannot be as strong as newer monoshock frame designs and with you putting out 100+ hp i would seriously consider trussing the frame. you eliminated the rear triangulated frame. so now you have just basically a hoop design.

this is just a thought, but i drew the way i see the forces acting on the frames. this is the original design with dual shocks. pretty straight forward. triangulation is one of the strongest things we know how to build, bridges are built with it, and there is triangulation between the swing arm, the shock mount, and the rear of the tank mounts. by cutting this off, i would worry that this might have impacted the rigidity of the frame.



heres your new frame, and the way i i could see the forces acting on this frame. the shock is now pushing the swing arm down, but also out away from the bike. and that swing arm will be constantly moving between acceleration and deceleration which will push and pull the swing arm mount which is now only connected by two small pieces of tube on each side. it used to be mounted between three, where there was no real way it could move in any direction, now there will be more force on those welds in a forward and rearward direction. i would think about trussing that swing arm mount before taking it on serious rides. also would consider what maxim-x said about the seat mount because your bodies weight will be pushing at almost a 90 degree angle on that small piece of tubing which is now the main structural support for the rear of the bike.



i love the build, amazing work. i just dont want to see it crack and fail , and you possibly get hurt, over being used time and time again. i love it!

 

Wow, that's some serious computing up there ^^^ sounds like somebody's an engineer? Architect? Something else?

 

My-other-XJ may be on to something. It may hold for now, but prolonged use could cause damage.
I would weld a gusset on each side of the lower frame rail(engine cradle) going up to the swingarm pivot housing and up to the downtube at the pivot housing. A couple of 1/4 by 2inch flat bar welded at 3 junctions-lower frame rail-pivot housing- downtube. Just to be on the safe side.

 

You make some good points. Thanks for the good advice with the visuals. I had my suspicions. I'll be doing some mods to the frame to beef it up. I'll keep you posted. I'm trying to get this beast running within a month (fingers crossed)!

 

I made some progress with the wiring on the bike. I can turn it on now and the lights turn on. I made some videos to show the progress.

YouTube video of bike no. 2
YouTube video of bike no. 3

 

Love it. impressive electronics!

 

I'm excited to see where this build goes. cant wait till its done

 

Very impressive.

 

Hey this is fantastic! Looks like you figured out the rear setup - did you have to end up swapping the disc after-all? I see you had to relocate the tank mounts as well - hopefully that wasn't the same hell as I went through!

Let me know if you still need pics but it doesn't look like it with the XV rear end. I apologize for not sending some before, got wrapped up in school/work :? .

 

I appreciate that! I owe a lot to you for the inspiration. I would have never known about the rear 900s wheel if it wasn't for you. Did you ever measure the offset the 900s wheel has on the xj750 diff? a couple of other guys where asking and I'm not sure. It doesn't look like very much? I moved the tank mounts in the beginning of the project, so it was hard at the time. It wouldn't be to bad now that I have a little more experience. It works well though.

 

Here is just a couple of samples I threw together from photoshop to see what paint scheme I might want to go with. What do you guys like? Any other suggestions or critiques?

 

The 1st pic needs a little more gold accent- it's too dark.
2nd pic would look better in a darker shade of red- the light shade doesn't mesh well with that shade of gold.
3rd pic-can't find a thing wrong about it. Don't care for white that much, but that goes together well.

 

I vote for the white but with a black or gold frame and accents! (depending on keeping the fork legs in it's current color or painting them black)

 

I used the string method to test for any deviation. It ended up looking close to, if not perfectly, aligned (the wheel does look a bit off in the frame but front to rear tracks straight). It's highly unscientific though and it may be worth doing a more 'rigorous' test.

 

My favorite is #1 paint scheme, it is almost perfect to my eye, i would add some gold around the number #82 (or whatever number) on the tail and on the pale part of the fairing lower.

 

So I think this weekend will be D-Day for cranking over the engine (fingers crossed)! I was wondering what you guys thought of this paint scheme on my bike. A cross between this race XS850 and the FZ750 paint scheme. You guys like or hate?

 

Personally I like a solid color with the exception of the old yellow and black Kenny Roberts scheme.

 

This is my personal favourite scheme, strangely since I normally like black/gold or metallic red but this scheme just seems to suit the bike so much better IMHO...

EDIT-: wow 1000 posts, I'm supposedly an "XJ Wizard" yet I've only been into them for 45 days!!!

 

You type too much :lol:

I like that color scheme best myself. It reminds me of this
Rick Hunter rocks!

 

I have a lot of time on my hands (when I'm feeling well enough lol)

 

any updates?

 

Update: I've been trying to get this beast to run with no success. Microsquirt is becoming quite difficult. I'm having a more concerning problem with the starter clutch grinding when I turn it over. It's pretty bad. I used Yamalube semi-synthetic oil & I think that might be the problem or a bad starter clutch? I drained the oil and refilled with conventional oil. The problem still is bad. Do you have to Change the oil several times to reverse the effect? The problem is that, I bought this engine without know the history on it. I don't know if it was the wrong oil or if it's the clutch? I might have to go out and buy another engine? Don't really want to do that, but it might be easier than a total breakdown & rebuild?

I have a good connection from the pc to the ecu. I'm having a hard time finding trigger impulse and timing when the starter clutch grinds after 1-2 seconds, very frustrating!

I'm fabricating a flush-mount gas cap from a Ducati Monster. I also just finished my tail reinforcement. It's strong as steel now.

 

The beast Lives!

youtube video of bike running

 

Super cool concept
Would love that front end and that undertail!

 

First test drive. Rev to 4000 rpm. It's not a great vid. I did it one handed with my phone, but I got it one the road! I need a lot more tuning. The ignition table is off in the mid rpm and my AFR is around 11.5 at idle.

Video of first road test!

 

I just uploaded a new video of the bike from a roadside perspective.

Drive by video

 

I friggin love it!
Thats a really brutal bike!

Now paint it already!!!

 

Awesome project.

You should put a link to your build thread(s) on the youtube page though so people can circle back to see more details.

 

That's a great idea! I need to do that.

 

This microsquirt is amazing and the tuning is infinite! Once you have an understanding, this is an incredible tool! You are no longer stuck with factory ignition setup. You can change anything in the engine and then just reprogram the ecu to the new setup. You can now reach the full potential of the engine that was once impractical. You can controll other things like boost for turbo or even nitrous oxide setup. I have my ecu turning on my headlight when it sees idle to save battery drain. If you want to learn and have the money/time, get yourself a microsquirt!

 

I have been contemplating this idea for a bit and now after seeing what farmer has done with his bike, I want to turbo! I have the XJ900 engine and I think it will be a real screamer.I hear the 900 lower emd shares a lot parts with the xj600 turbo. I'll need the oil pan from the turbo for the oil plumbing. I'm not sure if they share the same oil pump or should I get a turbo oil pump? I've been looking at turbos online and not really sure what size of turbo to go with? I went to the Garrett turbo website and looked at their turbos and thought maybe a gt20 series would be a good one? I liked the gt25 series because it's small and has ball bearings. Farmer said he had a gt25, but thought it was too big. With mine being a 900(853cc) engine, would it still be too big? I would move the oil cooler to the back of the engine in front of the swing arm at an angle to catch the under draft. I might modify the sandwich plate on the oil filter to accept "AN" fittings and make some custom lines back to the oil cooler. My goal is 150-175 hp, if not more. I'm starting with 97 hp stock. I have Fuel injection and electronic ignition. What do you guys think? Any opinions on turbo size for the 900 or any other parts/ mods to engine?

 

1st of all I love your build on the XJ! I am looking at doing something like that in the future!

With turbo I think you should go for the gt25 series as it has ball bearings! the turbo in my car has no ball bearings and went to sh!t!

keep us posted mate!

 

I've been cramming lately on the turbo idea and learning a lot. I've been scratching my head as to how to feed and return oil to the turbo? The xj650 turbo has an oil pan with a oil fitting mount. Is that for the oil return? I've read that you want the oil return above the oil level in the pan? Where can I tap for oil to feed the turbo? Do I put a tee on the oil cooler line and supply it from there or is there another source on the bike to tap from? The turbo needs to drain then oil by gravity and should not be below the oil return. I guess you need to be able to pump the oil out if it is? Could anyone shed some light on this for me, specific to the XJ bikes?

I'm still not sure on what turbo to go with? I think the T25 will only start to spin around 8,000 rpm at my estimation. The gt2052 seems like a good candidate with the compressor map. It's a journal, but I don't know of a smaller ball bearing turbo than the gt25?

 

I've been watching your build on youtube, here and the streetfighter forum.

After seeing everything you've achieved so far I'm sure you can work out a turbo.

But if that turbo is only starting at 8,000 forget it, there must be something small enough to spin from 6,000.

I would love a turbo on my XJ750 Cafe Racer but couldn't afford it, plus I would be uninsurable.

 

Great effort,
I would say your best bet is to get a manual for the XJ turbo bikes and use it as a baseline to reverse engineer a solution for your application. There will be improvements to make. I wish I had turbo bike knowledge to share with you but I do not in this application.
Have you considered supercharging? You can buy a rotrex viscdrive derived supercharger, bolt it on, tap the crankshaft, shove the intake onto the airbox, seal it up and awy you go with the megasquirt for control.
Fitting a SC and maybe a FMIC on there will be a challenge to your aesthetics.....
The other consideration is the lower compression ratios of forced induction bikes, If you're only planning on running low boost then maybe not such an issue but higher compression (relatively) motors won't take too kindly to high boost applications. Traditionally, one would aim to do some head work or change stroke to lower CR before applying forced induction. Superchargers aren't laggy like turbos but if you're thinking of correctly matching a small one, this won't be much of an issue anyway.

 

I've been doing some number crunching and bought the turbocharging performance handbook by Jeff Hartman. This is a great book with all the equations needed to design a turbo system. I'm still having some confusion though. It looks as though to get 190-200 hp @ crank, you need almost 20 lbs of boost! This is not going to happen on a road bike. My calculations are this:
air flow requirement
AF= HP x AFR x BSFC/60
AF = actual mass airflow in pounds per min
hp = target flywheel horsepower
AFR = air/fuel ratio
BSFC = brake specific fuel consumption in pounds per horsepower x hour ( /60 to convert hours to min) usually .55/60

I'm taking 150hp into the equation

150 x 11.5 x (.55/60) = 15.8 LB per min of air required

know I need to calculate the manifold pressure required for the air requirement.

MAPreq = (Wa x R x (460 + Tm)) / (VE x (N/2) x Vd)

MAPreq: manifold absolute pressure (psia) required to meet the horsepower target
Wa: AIRFLOWactual (pounds per min)
R: gas content = 639.6
Tm: intake manifold temperature (°F)
VE: Volumetric efficiency
N: engine speed (rpm)
Vd: engine displacement in cubic inches

MAPreq = (15.8 x 639.6) x (460 + 130)) / (.89 x (10,000/2) x 52.05)

MAPreq = 25.74 psia

This is actual pressure. Subtract atmospheric pressure to get gauge pressure (A.K.A. boost)

boost = 25.74 - 14.7 psia (at sea level) = 11.04 lbs of boost

By the way, my engine is a XJ900(52.05 cu.in.). It has a VE of .89 and creates 9.68 of air flow naturally aspirated.

My understanding of boost is that 1 LB of boost creates between 9-10 hp. If that is correct, 11 lbs of boost should be 99 - 110 hp extra? This must not be the case. I also see that by adding up to 11 lbs of boost, I'll effectively have a compression ratio around 11.5:1 from 9.6:1. I think that should be safe with premium fuel(92-93)?
Running that high of boost concerns me as whether I'll need a intercooler or not? There is not much room and I also need a larger oil cooler. The one I have now is not great. There looks to be room in front of the rear tire. I know the factory originally put the turbo there, but I'm looking to stick it in front of the engine like Isaacson06. I might try and fit a oil cooler back there and put a intercooler in front?

I'm throwing a lot of math here, so I hope I don't lose you guys.

My figures came out to 2.02 pressure ratio & 7.9 lb of corrected air flow for max tq @5,00 rpm and around 12 for max hp @9500.

I'm still not confident in these figures and need to bounce them off someone. I called Mr.turbo in TX and they told me they wouldn't be able to talk to me for at least 2 weeks! Garret turbo won't return my emails and other companies aren't helpful. I looked on garrett turbo website and found that the gt2052 (2) turbo map looks like it might be the right one but I might be way off? I could really use someone with experience here.

 

Interesting,
I don't know anything about the book or the author. I guess he must be a very accomplished engine builder. However, it seems that these equations are a bit rounded rather than specific. Your calculations check out for the numbers you have used.

is R the gas content or gas constant?
Using ball park figures is good for a generic understanding but be wary for specific design like the one you are undertaking, by using ball park figures you risk either being disappointed with your final HP output or buying a mismatched turbo that cooks it.
I would always go for an intercooler if i were going for a high boost application/ and or its possible to fit, but have a bike running without one and just an uprated 2nd oil cooler. I run just 9psi of boost max but have more ccs and a lower CR to start with (8.8ish). I've found on hot (100F plus) days in traffic, the beast can overheat and i have to keep an eye on coolant levels.
Regarding octane, i never go less than 98 RON, although it will run ok on 95 (same as your 93 AKI). The high octane pump fuel in Europe is higher than in the US and Aus so its less of an issue but you can always drop in some booster to each tank. You wouldn't want to be hitting high boost with lower octane in too much, but its ok for normal road riding.
Intercoolers don't typically increase horsepower as we may calculate (cooler air=denser charge= more fuel burn=more power.... in theory), but they guarantee it for a given ambient temperature and they also add a safety factor to the engine.
Looking at the Compressor map with the numbers you have, aren't you a bit on the edge with the 50 trim?

If you just want info then these guys are some of the best
http://www.turbotechnics.com/
in the UK, so you won't necessarily want to buy from them but they have always been good at getting back to me. Pop them a mail or call if you can deal with the accents.

Great effort for getting on this, I'll be watching the progress with interest.

 

Have you seen the garrett boost advisor.
Great tool. It basically does all those calcs for you in a very gourmet application
http://www.turbobygarrett.com/turbobygarrett/webadviser
It comes up with the same unit you have displayed the map for, above.
I'd go with the smaller trim 48 to keep the mid range away from the surge line.
Anyway, the point is, you should have more confidence in your calcs.
Have you looked at KKK, perkins etc. they may have other options although the specs will be identical but the packages may be cheaper new and 2nd hand.

 

Thank you for the advice! I checked out the app that you mentioned and double checked the math. I came up with having the gt2052 "48 trim" as well. I think this is what I'm going with. I checked out bell intercoolers website and found they have 2.25" thick intercoolers that will be safe to install where the oil cooler is now. A 7.5"L x 5"H x 2.5"w has 329 cfm. This is plenty of flow for what I'm building and can be completely custom made.
Earl's performance makes a 2" thick oil cooler that I'll mount underneath the bike. The collector currently under the bike, which is 4" in the front of clears the ground well. I should be ok, in therory.

oil cooler Example:

 

Good show.
No doubt that thing looks unique. But to my eye, it comes back to my comment about it being an aesthetic challenge to fit an IC.
I think, thus far, your build is a very attractive bike and hanging a large IC and/or OC out front could upset the looks a bit. Especially when one considers the additional pipework to re route back to the intake.
An engineering challenge to maintain aesthetics.
It might be that going beefy, steel and industrial makes it look like a real beast, difficult to judge until seen.
Best of luck

 

Thanks for the complements! I agree that a huge intercooler mounted upfront would be blocky and ugly. The one I'm looking to build would not be much larger than the current oil cooler mounted. I'm going to do some mock ups this weekend to see how it might fit. Having the oil cooler under the bike will be a way to make it less compact. I can also have a larger oil cooler mounted underneth, because of the larger area. I would have to fab a ram air effect to grab the air flow.

example:

 

I would consider a gt20 series vnt turbo for your 900. here it is compared to the gt1749v, which I am using. THis is the stock turbo from a jetta tdi diesel. (mine). You may also find my turbo works well on the 900, but it could start to become a little bit on the small side. Run the numbers on it. About the HP gain, I am not sure but at 9~11 psi that I am am running the bike is getting pretty quick, 11 psi it cannot hold the clutch back with EBC HD springs and EBC friction discs. I want to say its almost double the HP, what is stock 65 engine hp for the 650? I would like to get it up to 18~20 psi once I upgrade the clutch system to handle it.

Here is a comparision photo of the turbos.
http://jsperformance.ca/gallery/albums/ ... .sized.jpg

In first gear, it spools at around 5 grand with the 650 motor. The VNT feature really allows it to spool quick. One problem though I have is that for some reason its gets bogged out right at the onset of spool in 1st gear. I have an AFR gauge, it reads 10.0 which is very rich. I am unable to lean it out, i think megasquirt is the answer so that I can control my mixture at any rpm or load. The other issue is that at cruise i generate between 1-3 psi boost at cruise rpm. However with megasquirt you may be able to electronically control the vane position of the VNT. THe benefits are much greater boost response and less backpressure as well as being able to spool a big compressor that much quicker..

That is a big oil cooler. Guess you could have it on a thermostat though if it allows the oil to get too cool. I am running the stock 650 turbo one in the stock 650 turbo location. I was thinking of going bigger.

 

Man I'm loving the bike, and had been doing some research into doing my XJ750 and realized I had been beaten to noticing the virago swing arm would look great (Damn! My originality is always behind the curve)... I'm not so sure about the turbo idea, because of the stress it would put on the head gasket. If you do it I would look into the possibility of twin turbos, and base it off of the '93-'96 RX-7 to help avoid turbo lag. It used a smaller turbo to help spool the large turbo in essence. If it were me, I'd leave it the way it is so I wouldn't blow it up, but I'm only looking at the ability to enjoy the fruits of my labor before they've spoiled... What the hell am I saying?! Frankenstein that bitch!!!!! :twisted:

 

I finally finished the tank flush fuel cap mod. I also adapted the fuel delivery as well. I welded the petcock location shut and replaced it with "an" male fittings on each side. I also fabbed a retun fitting with a extended internal hard line spraying away from the fuel out port.

 

What fuel pump are you using? Is it in the tank?

Thanks
Nate

 

Hi Nate, it's a '99 Hayabusa external fuel pump with built-in fuel regulator.

 

I'm actually going to be upgrading to a Waldron inline with a aeromotive fuel regulator for my turbo setup. The hayabusa pump works well with the current setup. It has a low amp draw

 

Does not having a sump in the tank cause problems when your fuel is low?

Thanks
Nate