- Wed Apr 10, 2019 9:14 pm
#9227
For Norm and anyone else interested, though really, this is for head-bangers only...
Rather than leave this at the end of ericpode’s sprag clutch thread, let’s start afresh.
Quick recap, Norm had what was probably the worst ever Electra-X to escape quality control back in the day and ended up rebuilding his engine into a mostly classic (iron barrel) 500 Bullet but still with the Electra-X timing cover and high capacity gear-type oil pumps.
Voilà !
But of course there is more than one way to flay this particular moggy (sorry, cat lovers). Instead of building the worst bits OUT OF and Electra-X engine, how about building the good bits of an Electra-X INTO a set of classic Bullet cases?
WHY???
Proper tappets and a chance to fit whatever ignition I like, for starters. Magneto, yes please. And BECAUSE!
Norm has identified a couple of issues in the other thread, but let’s see if it all fits together first, I’m using a Lucas SR1 magneto instead of a BT-H electronic one this time but staying with a Dell’Orto PHF carb. One of our hosts’ performance Electra cranks will be fitted.
Yes it does fit, just! The cylinder fins have been trimmed at the back to allow room for the mag, but I shall have to trim about another 3 or 4 mm off to get the same gap as Redditch SR1 fitted 500 Bullets had. I can probably get a little more mag to carb clearance once all the gaskets are on, perhaps with a 3 or 4mm tufnol insulator between the carb and the manifold. If not I have found a source of the older Dell’Orto rounded float bowls. The camera angle exaggerates the closeness to some extent. Having to clear the make makes the carb cit back further than I’d like, but a quick check against frame and tanks shows it will be OK.
On the other thread Norm was alluding to the fact that the oil holes on the scavenge side of the timing chest don’t line up if you’re fitting an Electra-X timing cover onto a set of classic crankcases. In fact there is only one. If you look at the picture immediately above you will see the two holes in about the 4 o’clock position if you think of the timing chest as a clock face. Notice the alloy blob in the joint face at the three o’clock position? That’s where the lean burn oilway on the AVL/Electra-X engine would be drilled into the oil passageway behind it.
So all we need is to drill out the hole in the AVL position and drill and tap the upper of the two existing holes for a grub screw to block it off. Like this.
This saves playing with extra-thick gaskets or trying to mill an oilway into the joint face of the timing cover. OK, this picture shows my current hybrid engine which did not have the blob in place, Henry Price had to put it in there with alloy weld (he isn’t doing any more!), but it shows where the new oilway has to go.
That’s pretty much it, apart from a bit of work on the Electra-X timing cover, the cam spindle housings need reaming out to â…†from 15mm to fit over the fixed cam spindles. Also the idler gear spindle bosses in the cover are only part-finished, as the Electra-X doesn’t have idler gears, so these need to be finished machined to let the cover sit properly.
Norm, you also mentioned the gap between the crankcase mouth and the smaller O/D of the cylinder liner, I shall check how much slop there is with the cylinder fitted on all off the cylinder studs, but I have a plan for taking up the slack with spacers if needed.
A.
Rather than leave this at the end of ericpode’s sprag clutch thread, let’s start afresh.
Quick recap, Norm had what was probably the worst ever Electra-X to escape quality control back in the day and ended up rebuilding his engine into a mostly classic (iron barrel) 500 Bullet but still with the Electra-X timing cover and high capacity gear-type oil pumps.
Voilà !
But of course there is more than one way to flay this particular moggy (sorry, cat lovers). Instead of building the worst bits OUT OF and Electra-X engine, how about building the good bits of an Electra-X INTO a set of classic Bullet cases?
WHY???
Proper tappets and a chance to fit whatever ignition I like, for starters. Magneto, yes please. And BECAUSE!
Norm has identified a couple of issues in the other thread, but let’s see if it all fits together first, I’m using a Lucas SR1 magneto instead of a BT-H electronic one this time but staying with a Dell’Orto PHF carb. One of our hosts’ performance Electra cranks will be fitted.
Yes it does fit, just! The cylinder fins have been trimmed at the back to allow room for the mag, but I shall have to trim about another 3 or 4 mm off to get the same gap as Redditch SR1 fitted 500 Bullets had. I can probably get a little more mag to carb clearance once all the gaskets are on, perhaps with a 3 or 4mm tufnol insulator between the carb and the manifold. If not I have found a source of the older Dell’Orto rounded float bowls. The camera angle exaggerates the closeness to some extent. Having to clear the make makes the carb cit back further than I’d like, but a quick check against frame and tanks shows it will be OK.
On the other thread Norm was alluding to the fact that the oil holes on the scavenge side of the timing chest don’t line up if you’re fitting an Electra-X timing cover onto a set of classic crankcases. In fact there is only one. If you look at the picture immediately above you will see the two holes in about the 4 o’clock position if you think of the timing chest as a clock face. Notice the alloy blob in the joint face at the three o’clock position? That’s where the lean burn oilway on the AVL/Electra-X engine would be drilled into the oil passageway behind it.
So all we need is to drill out the hole in the AVL position and drill and tap the upper of the two existing holes for a grub screw to block it off. Like this.
This saves playing with extra-thick gaskets or trying to mill an oilway into the joint face of the timing cover. OK, this picture shows my current hybrid engine which did not have the blob in place, Henry Price had to put it in there with alloy weld (he isn’t doing any more!), but it shows where the new oilway has to go.
That’s pretty much it, apart from a bit of work on the Electra-X timing cover, the cam spindle housings need reaming out to â…†from 15mm to fit over the fixed cam spindles. Also the idler gear spindle bosses in the cover are only part-finished, as the Electra-X doesn’t have idler gears, so these need to be finished machined to let the cover sit properly.
Norm, you also mentioned the gap between the crankcase mouth and the smaller O/D of the cylinder liner, I shall check how much slop there is with the cylinder fitted on all off the cylinder studs, but I have a plan for taking up the slack with spacers if needed.
A.
