851/888 racebike basketcase

nix510

851/888 Racebike Basketcase

A beautiful project by the way, very inspiring, but a question. Where did you source the C/F early rear seat from? It appears very well made.

BARONROJO

Matching the wiring loom is not a problem. On the 851 you have two +12 V wires, one for the pump and one for the fuel sensor. The ST4s is different as there is one +12 V, the fuel sender being connected to earth in this case. As you won't be using the low fuel warning light, there's no problem. If you want to use it sometime, you can connect it to the only +12 V wire that feeds the pump. The only issue is that in low fuel condition when you switch the contact on the low fuel comes on as the pump primes the fuel system then off, then on agin when the engine starts turning. No problem!

By the way, gooooorgeous bike, excellent work, mate!

By the way, a cheap source to get the fuel pump. I bought it from this seller and it fits perfectly!

nine16

nix510 wroteA beautiful project by the way, very inspiring, but a question. Where did you source the C/F early rear seat from? It appears very well made.

It is a little bit heavier than some thin cf, but extremely sturdy (and still light). I got it from webike.net in Japan. It took 2 months, but they told me it would. I got the race version with the close off rear. Not cheap, but not brutal with the weak yen to dollar.

nine16

BARONROJO wroteMatching the wiring loom is not a problem. On the 851 you have two +12 V wires, one for the pump and one for the fuel sensor. The ST4s is different as there is one +12 V, the fuel sender being connected to earth in this case. As you won't be using the low fuel warning light, there's no problem. If you want to use it sometime, you can connect it to the only +12 V wire that feeds the pump. The only issue is that in low fuel condition when you switch the contact on the low fuel comes on as the pump primes the fuel system then off, then on agin when the engine starts turning. No problem!

I was referring to alternative throttle body options, not the pump. But nice to know about this one. I had heard Mazda MX5. Do you know what pressure this runs? Doesn't say in the auction. I was thinking of running 3.5 or 4 bar even with the higher flowing injectors.

BARONROJO

Unfortunately not. I'm using an OEM S4R pressure regulator as it's a road bike. Un runs perfectly but I haven't tried another layout..

Mr.R

I've the later steel tank on my '92 851/916cc motor that has as standard a smaller (pattern*) pump than those fitted to the alloy tanks/Corse motors.
I've been running at 4.5 bar for several years now with single "Green" injectors per cyclinder without any problems, my 916cc motor's only making 128 rwbhp @ 9,200 rpm 76'8 ft lbs of torque and at no time does it run out of available injector time on a full custom map.
It also uses less fuel now than it did as a standard '92 851. 😎
All the Corse motors/chips were designed to run on 5 bar pressure. I'm sure that either the early Big or later small pumps are more than up to the job even when running as high as 5 bar.
The later smaller pumps were OEM fitment on Mazda's, Toyota's and Ford Mustangs, if they can supply enough fuel for these cars, they shouldn't have a problem supplying a twin cylinder bike motor in a fairly soft state of tune.

*The pump came with a 2 year warrenty, so I figured that if it died inside of that I'd get a new one for free...
However it's still happily running along as good as the day I fitted it.
I have got a spare new one tucked away just in case now though as you do. 😏

Steve R

marvin

My '92 851 now has 64K miles on it with a 999 Testastretta engine, pink 12 hole pico injectors and the original fuel pump is still working fine and provides enough fuel. At around 30K miles when I built the original 851 engine into a 907CC engine I bumped the fuel pressure regulator up. (If I remember correctly it was 5 or 5.5 bar) (not a corse pump).

griff851

nine16 wroteI was referring to alternative throttle body options, not the pump. But nice to know about this one. I had heard Mazda MX5. Do you know what pressure this runs? Doesn't say in the auction. I was thinking of running 3.5 or 4 bar even with the higher flowing injectors.

All the car pumps run at 5 bar, its pretty standard sort of thing.

Viper1

nine16 wroteCarbon fiber arrived. I'll have to do a little modification to the bottom mounts because of the 888 style rearsets. I'm figuring out tank internals to run a little higher fuel pressure. The ST4S single injectors are getting sent out for machining for higher flow. But then at least it should all be plug-and-play with the Microtec ECU.

Keep the exposed carbon visible and have Jason paint Ducati red around the edges! WOW!

nine16

In the interest of keeping this build from becoming a complete bitsa, I had RC Engineering clean, refurbish, and bore the original ST4S injectors to increase flow from 330 to 450 cc/min at 3 bar. That should give me enough juice for 140+hp.

Picked up all new tank internals to feed those injectors.

Seems like the ST4S throttle bodies dont line up for the 3 piece box, so I'm going to try my hand at fabricating my own custom airbox and I've picked us the carbon fiber for that project. Well see how it turns out.

nine16

Viper1 wroteKeep the exposed carbon visible and have Jason paint Ducati red around the edges! WOW!

He going to do red with normal white boards but Adamo's number 26 will be entirely exposed CF. Same on the front.

nine16

These arrived today. Why? because you never know when you'll need to spontaneously change your brake calipers.

marvin

nine16 wroteBy the way--anyone know which smaller temp guage fits the 53mm hole? The 996 one I planned on using is 58mm.

Satandard 851/888

p.s. Plus, you have to use the matching temp sensor. The 996 one won't read correctly in conjunction with the 851/888 temp. gauge.

nine16

marvin wroteSatandard 851/888 p.s. Plus, you have to use the matching temp sensor. The 996 one won't read correctly in conjunction with the 851/888 temp. gauge.

Ok, I guess I'll try to enlarge the hole without butchering it.

Viper1

Find a 91-98 900ss temp guage.....same one as the 851/888.....they were all over ebay a few weeks back.

nine16

Did I misunderstand or didn't Marvin say it wouldn't work with the ST4S harness?

Wait a minute--why would an air cooled motor have a temp gauge?

Claire4dukes

For Oil Temp...

Viper1

I was under the impression that even though it's used for the "oil" temp on the 900ss, that it could be used as the plug in is identical on a 851/888?

nine16

I know they have an oil temp gauge but didn't think those would be similar enough to the coolant temp ones. Anyway--can anyone definitively saw whether they would work for coolant with an ST4S sensors and harness?

marvin

The way I would find out it to plug it in and try it. Or I guess one could use a VOM and check the resistance. I would also compare the resistance of the 851/88 sensor against the ST4S.

BTW, If I were going to try and enlarge the hole in that CF dash I would use a flex-shft (or a dremel, Yuck) and grind it. Wear a respirator and gloves, those CF splinters are nasty as is the dust!

When I worked for Parker Guitars I had some experience with CF as our fretboards were CF and glass cloth. We tried water jet to trim the edges which worked only marginally well but ended up using a saw with a diamond blade. Our frets were stainless, rockwell 56, so that did compound the problem.

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