Forum

[Bet]

Could anyone tell me if it is normal to change exhaust cam and follower on a 2007 electra nearly as often as changing the spark plug. Had the engine seize at 6500 miles, fitted new cams, followers and guides. Head broke off exhaust cam follower again at 10000 miles ish,dropped between cams and once again lock up at 60.

[Adrian]

No (unless you're very unlucky), but as it has happened to me only once so far on my Electra I shouldn't be too assertive about this.

If the Electra-X cam follower housings are the same outer diameter as the earlier classic Bullet items I'd be sorely tempted to fit a set, as the stems are noticeably thicker. Ideally our hosts would have pt. number 90150 available again. You'd need the old-style concave adjusters and if my experience of building Lean Burn/classic hybrid special with Redditch "S" profile cams is anything to go by, you'd need longer pushrods too (about an extra 3/8"). In my case I used the AVL exhaust push rod for the inlet, as it was already the correct length, and for the exhaust I modified the exhaust pushrod from a 500 classic to suit. You can also use standard Bullet cams for a minor performance boost if you're doing this, but the piston crown will need a slight cut out for the edge of the inlet valve.

Regards,

Adrian

[Norm]

Bet are you using the decomp to stop the motor if so this can break the head off the tappet giude. Adrian I fitted Bullet tappet guides in my crosbred but I had to turn them down to fit in the Electra cases

[John N]

Norm, can you explain how lifting the tappet away from the cam can break the head off the guide? I ask as I cannot see any excess forces in play. I am genuinely interested to know, not criticising as I always use the decomp on my electra to save the sprag and take all stresses out of the equation. As a Chartered Engineer this makes sense, am I wrong?

[Bet]

Adrian, Norm. Cheers for the replies, given me some ideas that maybe worth a try.
Decompressor went with the starter and sprag clutch back in 2008. I like things basic, so less to go wrong (if only I could find a way of junking the cam follower).

[Adrian]

The AVL cam followers really seem a perverse bit of the AVL re-design that has been overshadowed by sprag and big-end failures. My guess is that by (over)slimming the stems down and reducing weight they were hoping to help the thing rev a bit more. Norm's solution of classic Bullet cam followers with the O/D of the guides machined to fit the Electra-X cases looks like your best shot at eliminating the problem for good. I feel your pain...

A.

[Norm]

John the problem is in part the fact the valve lifter operates on the exhaust valve tappet and to get this to fit they reduced the diameter of the tappet stem from 9mm on a Bullet to 6mm on an Electra. Adrian when you machint the tappet guide, the recess in the Electra where the guides fit is deeper than on a Bullet so you have to machine the guide so that it sits at the same height that it does on a Bullet or in other words so that the same amount of guide sits through the case as it does on the Electra. I may have a guide here that I machined but I think it was 40mm long and about 1mm taken off the diameter. No problems with over 30,000ks on that setup

[Bet]

Maybe a wait before our hosts have any 90150 followers and guides. As this is my daily hack, could anybody suggest what year/era engine to look at for parts? On further investigation it appears that the exhaust cam spindle has been rotating and taken out the flat spot in the case. Could prove my theory that Indian metals come in two grades, milk and plain.

[Norm]

Bet, no flat spot on the spindles they are an interference fit in the case

[Adrian]

If the cam spindle has been rotating in the crankcase hole something is definitely wrong. As Norm says, they're an interference fit in the crankcase. I guess you heated the crankcase up to extract the spindle, so that you could get the cam follower guides out safely. Trying to extract or refit the spindle (or guides) from or into too cold an alloy casting might have destroyed the interference fit, allowing enough clearance for the spindle end to rotate. However, if I remember right, on the classic engine there is also a partly ground away flange (is that the flat spot you're referring to, Bet?) immediately above the section of spindle which sits in the case. This is meant to sit snugly in a recess in the crankcase casting as a further means of stopping the cam spindle from rotating, but could have failed if the spindle wasn't refitted properly. Please forgive my stating the obvious if you actually did it all properly both times! Our hosts' notes on fitting performance cams to the classic Bullets sort of show what I mean, Norm will correct me if the Electra-X is substantially different! http://www.hitchcocksmotorcycles.com/pi ... mshaft.pdf

The only other thing which springs to mind is an intermittent partial seizure of the camshaft bushes, they're steel on the Electra and other Indian Bullets, whereas Redditch Bullets used phosphor bronze. The exhaust cam on my Electra was showing signs of this with some bush material needing emery-ing off the spindle outer, and the cam replacing.

As for the model year for classic Bullet parts to carry out Norm's modification to your Electra, the cam followers and guides for any late classic Bullet (NOT the EFI Classic!) will do. So far as cam spindles go, it sounds like you will need an oversize version to fit where the originals were spinning. If you check parts search you will see our hosts list them in both ajustable and fixed versions. Fixed cam spindles might result in a slightly noisier engine, but they're one less piece of maintenance to worry about!

Regards,

A.