Pumba the XJ750 project

Those manifold are a work of art... Love the direction that you are taking this old beast!

 

I am wondering how much extra gas mileage and HP u gonna get after finished.

 

Silicone hose turned up and the throttle bodies now stay put.

As the throttle bodies are mounted further apart than the FZ6R that they came off, its time to make spacers and extend the linkage between the 2 throttle bodies.

This is the gap;



Easy to make spacers, but the throttle arm extension ended up a bit different as I wanted to avoid flex.



Because of my concerns with throttle linkages coming loose, I used spring washers and locktite and then put heat shrink over the lot. If it comes loose, it has earned the right to.



Upper and lower spacers fitted;



Linkage closeup





820 big bore kit and barrels are at the machine shop for boring and honing

 

New bits


Hope to have the microsquirt driving the ignition coils in the next week

 

So nice! There is nothing better than raw material machined into something like you have done here! Your bike has come a long way, and now it is being sent into the future! It was a motorcycle stuck in its own age, but now it has met the 2000's!

 

I want to know what kind of dog is supervising this project......

 

the feline kind.

Following along because I love these kinds of builds. I have another friend in your neck of the woods that has his own milling equipment and built a 350hp LPG power Toyota Supra pretty much from scrap. Cant wait to see what you make next.

 

Sometimes ideas don't work, so here is a limited edition soon to be changed idea.





I will be running 4 coils, two will fit in the original position, and 2 need to be mounted elsewhere.

Not happy with this set up, but it may be used for a short time.

Next update will be engine rebuild stuff.

 

More pics of things happening;

Same old, same old;



something new;





And it fits;



Now a nice thing about setting up the ignition with the Microsquirt ECU is the fact that the ignition offset is adjustable.
If the missing tooth is set incorrectly in relationship to TDC, you can just adjust the programming accordingly.

Time to weld both together.

 

I think the coils above the valve cover are bad azz, it looks like how they are on the GM LS v8s.
All 4 down there would be sinister.

 

ECU case project



Wires have silicone insulation, not vinyl



Final assembly (after it is running and all clear of bugs) will have heatsink grease underneath the main switching drivers and be encapsulated.

 

Now that is just too groovy! Nice work!

 

Excelent job Darkfibre you r way above the weekend mechanic I am. And for that reason I think I will have to give up my idea about moving to EFI I am way less skilled than you so I would never been able to do things like that. You job is professional grade

 

Please don't be discouraged from doing a conversion by looking at my project.

Some people dedicate time to their hobbies and go a bit far, be it gardening, painting, pigeon breeding or computer animation.

Using my ECU housing as an example, it is what I visualized, and hopefully it works OK. For $150 more I could have bought the ECU in a sealed factory case complete with a wiring harness.

I also intend to over design the air cleaner assembly, which may or may not work in its first version, but it will be aluminium

My project goal is not just to put EFI on Pumba, but to combine it as part of the full project and hopefully not look like a quick addition.

 

Darkfibre, you must be a Engineer by trade or some equivalent talent eh? I like your work and the direction you are heading but just how much is all of this costing you on this make over? Is this not beyond the average persons price range? I wish I knew more about these things myself but to be honest I am old school. Since black and white computer monitors I have built my own computers ect. but I can see you are way beyond that sort of thinking for sure. I remember the first XJ Seca 750 I saw, the first thing that went through my mind was the head design, made me think of the old Chrysler Hemi and then made me question just how much could be acheived by re-making the 750 with todays technology? I think you are headed down that road. It will be interesting to see just what you end up with in Power, and reliability. grunt007, 81'XJ Seca 750R

 

My only qualification is as a motor mechanic, but most of my career has been in EFI and vehicle electronics with a few years as an instructor teaching EFI to mechanics. Also spent a few years in IT up to CCNA level.
No machinist training, just had access to the gear and decided to wing it.
Currently I repair ECU's and do phone support for mechanics that need diagnostic assistance.

As for cost, my budget is imposed at $300 per month including buying tools or equipment. Without the budget restriction it would have been finished more than a year ago. I think the finished project will probably be 4 years and $12,000 there about.

 

Hmmmm...If a hundred of us put up cash,how far could the price drop? I'm not looking forward to cleaning my carb's every year or two.I'm a recent returnee to motorcycle riding( wife is now ex-,kid is "grown" and on her own).So riding is again a part of my life.I'm even thinking about moving far enough south to ride 10 months/yr.With the inevitability that fuel WILL have more etoh in it (got to make corn-agribusiness happy,after-all)and if I want a shaft-driven upright riding position non-German bike,then everything which can be done to extend the riding-life of my machines will pay itself back in HAPPY-time.I'd gladly lay down a "few" thousand(3-4,000) for a chance to have my own "Back to the Future" Bricklin-stylee SECA.After all,I've spent many thousands on my bicycles,what's a few more for my motorcycle?.I alternate two wheel mode of commuting,hate to admit it but I have WAY more fun on the SECA and I've never returned from an XJ ride red-faced,and gasping for air.(NOT that I'll give up the self-propulsion mode,however the farther I get past 50,the harder it has become).Any way,how feasible would limited mass-prod. be?

 

Just a mention that the EFI system has cost only a fraction of the Pumba project. Still well under $1k and that includes buying the rotary table to make the manifolds. Time spent is a different matter.

If I was doing a set up that could be scaled up for a limited production run, I would do it differently, and try to use off the shelf items and avoid the custom one off items.

In theory the manifolds could be mass produced, and a single piece ignition trigger wheel as well.
I think a direct bolt on trigger wheel for an XJ bike would be worthwhile for people doing a project if only due to the fact it could be provided with ECU settings that would save people a lot of set up trial and error.

With an identical trigger wheel, manifolds, throttle body, coils and air cleaner the ECU would work with a copy of a previous tune, with fine tuning needed for different fuel pressure or exhaust etc.


Question is premature until I have a finished system.

 

A decent update is overdue, but here is a pic from last weekend at the staging area for a charity ride



I am not in the pic