Monday 27 January 2014

Petrol tank and pump

I now have an mc22 petrol tank complete with inbuilt fuel pump, filter & pressure regulator assembly.

Using the mounting flange which I cut from the ZX6R tank, I cut a hole in a spare mc22 tank and welded the ZX6R mounting flange in place. Pressure tested for leaks and all is good. The tank will need a clean out before use but is otherwise ready to go.

Flange welded in place

With pump installed

Wednesday 22 January 2014

TPS mount & plumbing

A little more work on the project over the weekend. I have fabricated a mounting plate on which to mount the TPS to the end of carb #1. This is simply a 3mm aluminium plate shaped to incorporate the TPS mounting holes and fixed to the carb through the top clamping rod and by way of a threaded hole into the side of the float bowl chamber. The clamping rod end needed an additional 3mm spacer in order to bring it level with the float bowl chamber.
The movement of the throttle will be transferred to the TPS through an M3 bolt whose head has been ground flat to fit in the TPS. The end of the throttle rod will been drilled and tapped to take the bolt. To fix the position of the bolt in place, both a locking nut and thread locker will be used.

TPS mount plate

TPS in approximate position.

The fuel pump mount has been cut out of the ZX6R tank ready for transfer onto the spare mc22 tank. It seemed a pity to cut up a perfectly good tank but all for the better!

ZX6R fuel pump flange

A mock mounting of the throttle bodies and fuel rail revealed that there was interference between the fuel rail and thermostat housing. Fortunately, I was able to overcome that pretty easily by adding an 18mm spacer underneath the thermostat housing mounting bracket. That pushed the thermostat housing down low enough to provide clearance for the fuel rail.

Fuel rail mock fitting (very approximate)

Ideas to deal with plumbing to the fuel rail have been run through also. The first option was to use standard threaded -6 motorsport hose fittings on one end of the fuel rail. That would involve a threaded adapter to sit into the fuel rail end. A 90 degree swivel fitting would then be threaded onto the adapter and lead onto the hose. The issue with this setup was side clearance on the fuel rail. The adapter and 90 degree fitting would need c.50mm end clearance to fit between the fuel rail and frame, which was not available.

The second idea was to run the same type of setup but with a 180 degree swivel fitting threaded into the bottom of the fuel rail and back on itself up towards the fuel pump. A quick CAD mockup of the carb bodies with blanking plates, injectors and fuel rail installed showed there wasn't the clearance available for this either.

CAD mockup of injector and fuel rail position relative to carb body

The final (hopefully) solution is to run a banjo bolt into the end of the fuel rail and clamp the fuel hose onto a barbed fitting. This would achieve something similar to the first  option but with less end clearance required. The other end of the fuel hose will be clamped to the original ZX10R fuel hose fitting to allow it to clip onto the fuel pump.

Friday 17 January 2014

Throttle bodies & wiring

A new year brings with it a new approach again and some good progress. First the throttle bodies.

The plan to fully modify the existing carburetors to become permanent throttle bodies has been changed again and simplified. While putting the exact modifications required down on paper, I discovered that there is not enough wall clearance in the carbs to fully bore out the step in the casting that forms a small part of the venturi. That realisation then snowballed to simplifying all aspects of the modification.
  • Instead of interference fitting a block of aluminium into the slide orifice and machining out with the rest of the bore, I will now bond the original slides in place, fill them with high temperature epoxy resin and take them out to match the carb bore by hand. 
  • The main jet protrusion will be drilled out and smoothed out using epoxy.
  • The protruding float bowl pieces will be cut down to the level of the float bowl mating surface
  • New blanking caps will be made up to fit where the float bowls once fitted and an additional piece fixed towards the front of the carbs to allow for good injector seats. This will become clearer in photos.
  • Any imperfections and gaps between the carb body and the new blanking plates will be filled with temperature resistant JB Weld.
  • The only professional machining required will be to drill and bore the injector seats in the throttle bodies and the fuel rail.
The major advantage to the new (again) approach is that the majority of the work can be done using basic tools and so can be done quickly. Even better is the fact I am already pretty much ready to send off the carbs and fuel rail to machine the injector seats. Photo's of progress so far below.

Float bowl cut down to seat face

Mock up of float bowl blanking plates

Detail showing infill of gaps with JB Weld for injector seat

Slide filled with JB Weld

Rough filling of drilled out needle jet

I have also been tidying up the wiring somewhat to make it the entire setup more permanent. More to go and there's not a whole lot to see anyway but some idea of what the old CDI area currently looks like is below. Including resistors hard-wired inline into the VRIN wires.