Hitchcocks Forum

Hi Everyone,

I've been having a read of the service manual for the Classic EFI C5. There is a section stating how the cam backlash should be checked and if necessary adjusted at 500 miles from new. The bike has just reached 600 miles now. I can hear a light ticking sound when the engine is idling but I'm not sure what sort of noise excessive backlash would make. I'm a long distance from the nearest service agent and wondered if anyone had any advice on doing this adjustment. In the manual, photos show the top end of the engine has been dismantled, and the connecting rod held in place with a special tool. I wondered, is it possible to remove the magneto rotor to see the cam gears without taking the top end apart? I'd be very grateful for any advice, the more I look the more I realise what I don't know.

Thanks, All the Best,
Hagrid.

You need to remove the rotor to access the cams (along with and a few other bits) but you don't need to touch the top end unless the push rods come adrift. The ticking sound could just be anything from the auto decompresser to the injector module or possibly backlash. There's an O ring that seals the oil pump against the main oilway. Lose this and shortly afterwards you'll lose the engine!

The problem with the W/shop manual I have is that it deals with a full engine strip rather than specific tasks, so it can be difficult to work out what actually needs to be removed to do a specific job. There is a good write-up in the March edition of RealClassic. As Ric says, you don’t need to remove the top end. IIRC the oil feed seal should be renewed at specified mileage’s too. Put a dab of grease on it to make sure it stays put when replacing the cover. In my w/shop manual the procedure is mixed up with the text for rear chain adjustment- don’t they use proof readers in India? I have to say, cynic that I am, that it’s likely that many dealers don’t bother doing the cam adjustment anyway. They make a racket if they’re loose.

Hi Hagrid, the backlash can be checked with out removing the push rods but it does make it easier as it relives the tension from the cams with them removed.



The right hand engine cover needs removing first, sometimes easier to tie this up against the side of the frame with a bungee hook and drip tray below as this avoids disconnecting the wiring that can be awkward to access as it goes through the engine mounts. The rotor then needs removing, ideally using the specific tool (part number:ST25128). The cam steady plate can then be removed which is dowelled and held on by three Allen screws (pay attention to the back side of this as there should be shims fitted to set the end float of the cams). With the cams exposed try to relive pressure from the hydraulic tappets and feel each cam for backlash between the corresponding cam and importantly against the crank spline with the exhaust cam. Adjust if necessary. It is worthwhile checking for backlash in a few positions as the cams may not be 100% concentric. It is also very important to not adjust the cams too tight as this is likely to cause a problem, its much better to have them on the slightly looser side and you actually want to be able to feel a small amount of movement between the teeth.




As previously said, on reassembly pay attention to the o-ring between the oil pump and cover and that this has not dropped off! A spare right hand engine cover gasket may be needed in case any damage is done to the original. Is it worth adjusting the cam backlash after such little mileage as part of the service schedule? Not in my opinion. The ticking sound you describe sounds more like the auto de-compressor which is located on the exhaust cam, at idle the cam is turning fairly slow and the de-compressor pin may not be pulled all the way into the its channel on the cam. This can cause the pin to just touch the roller on the hydraulic tappet as it rotates and give off a "ticking" noise, when the revs increase the pin turns fully into its channel and the noise usually goes away. This is normal for the EFI engines and would not usually be a cause for concern.

Sorry folks, I should have checked back on the forum before now. Thanks for getting back to me with the info, I feel a lot easier in my mind now.
Here's hoping the good weather is here to stay.
Best Wishes,
Hagrid