Tightening the banjo and this pulled out. Is it a modified ET100? My head still has the standard thread although not used when this component is in place.
ET: Engine (Twin) Modified ET100?
- Thread starter Dave Dixon
- Start date
Yes it is a non standard part, manufactured to stop rocker tunnel wear in the cylinder head, but the thread has stripped out leaving a small threaded component loose in the aluminium rocker bearing, I would advise not running the engine until you rectified the problem with new components. I think the Club Spares Company sell them, or failing that try Maughan and Sons, probably referred to as "Locking Rocker Feed Bolts"
Peter, thank you! The bike is safely up.on the bench so won't run until I've fixed it. My previous twin had a similar mod but it was a home grown version so I needed to find out what was in the head this time! Regards, DD.
That is the modified rocker feed bolt. The "hat" that sits inside the rocker block accepts the threaded portion that shows signs of being worn away.
Most likely will have to replace both the rocker feed bolt and the hat. But, check all components first. Might be wise to look at the others while the engine is down. The screw, 188, can be hard to remove on the front cylinder intake side. Some people shave them down a tad. If you replace ET188 copper washers, make sure they are flat. A quick buff on very fine sandpaper/glass will make short due of this. Usually just a few seconds in a figure 8 motion. The 189 lower seals that sit at the base of the banjo feed line that the spares sell works great. Hope this helps, Alyson
Most likely will have to replace both the rocker feed bolt and the hat. But, check all components first. Might be wise to look at the others while the engine is down. The screw, 188, can be hard to remove on the front cylinder intake side. Some people shave them down a tad. If you replace ET188 copper washers, make sure they are flat. A quick buff on very fine sandpaper/glass will make short due of this. Usually just a few seconds in a figure 8 motion. The 189 lower seals that sit at the base of the banjo feed line that the spares sell works great. Hope this helps, Alyson
I would dispense with the metering wires.They only deprive the rockers and cams of oil.
Hi Alyson & thanks! This was a minor "stop the oil.leak" job. This is what so often happens isn't it? The 188 came out easily - maybe shortened already - & thanks for the copper washer suggestion. I've never bothered to do that but now consider myself told! DD.
Do away with the silly copper washers and use small Dowty type seals........that is...... a small washer with a rubber seal bonded into the center of it........that way you do not need to over tighten the 1/4" BSF clamping bolt to seal the banjo against the lower sealing washer........over tightening the bolt will not only pull the small thread on the ET100/1 as you have found but it readily splits the lower banjo washer and then leaks get worse. Ideally you should do all four of these at the same time.........you need to remove the pushrods to remove the rocker bearing assembly, this will involve removing the fuel tank first........Quite a big job but well worth doing it correctly to save leaks appearing.........Cheers.
Another tip (you seem to have plenty now!) is to use a 1/4” BSF screw with a larger head (5/16 size) in place of the 188 screw. They are used on Amal carburettors. I bought mine from Middleton’s (third line down): https://www.stainlessmiddleton.co.uk/32911-bsf-bolts-setscrews this spreads the load out a bit on the banjo.
Hi Greg - yes, tank already off so not a problem. On my previous Twin one of the rockers split due to incorrect assembly (previous owner!). I was able to remove the pushrod & rocker arm at the roadside - then rode the bike several miles on one pot to catch the Douglas IoM ferry home. I'll try the Dowty washers. Already have a Velo so should have thought of that . . .
Cometic sells a gasket for that application that works just as well as a Dowty washer