Throttle and choke cables

[montmil]

If there is no ridge guide on the throttle cam gear

... clean the grease off and look again.

Speaking of, I need to lube said gears. any particular sort of grease recommended?

Exact question popped up on the Airlist couple days ago. Consensus is to use a "cold temperature" grease. I've used a high temperature grease in bearings but not sure what a "cold grease" specs at. Maybe just a dab of plain ol' grease-grease?

I use a very light application of white lithium grease.

[Barry]

I confess mine don't get cleaned and lubed every year, more like every 2 or 3 years. They must be due and this time I'm going to try moly grease on the grounds that normal grease turns black with wear particles from the pot metal gears so clearly it isn't good enough at preventing wear.

[Barry]

Cleaned and lubed mine today.  The throttle tube gear was a little worn even at only 21,000 miles but only the first few teeth. The cam gear must be mad of sterner stuff because I saw no evidence of wear on that at all.

There is an alignment mark on mine but frankly it's not particularly useful or needed. It's obvious if the gears are not mated correctly as one tooth out either creates too much free play or in the other direction holds the throttles open.  There is only one position that works correctly.

Those with twin cable throttles will know how much fun it is getting that little block on the end of the cam chain connected to the two cable nipples at the same time and then the top cover replaced without one of them slipping out. I've done it a good few times now but I don't think I'm getting any better at it.

[montmil]

Those with twin cable throttles will know how much fun it is getting that little block on the end of the cam chain connected to the two cable nipples at the same time and then the top cover replaced without one of them slipping out. I've done it a good few times now but I don't think I'm getting any better at it.

My 1978 R100S has the twin throttle cables. I fought 'em a couple times until I started using a simple trick.

The butterfly valve return springs create the tension problems associated with refitting both cables and getting the top back on without one or both cable ends popping out of position. Use a couple of small, wooden blocks to hold the butterfly valve in the full open position. Tension is removed from the cables and getting all the bits in their correct location is much simplified.

[Barry]

The butterfly valve return springs create the tension problems associated with refitting both cables and getting the top back on without one or both cable ends popping out of position. Use a couple of small, wooden blocks to hold the butterfly valve in the full open position. Tension is removed from the cables and getting all the bits in their correct location is much simplified.

That's pretty much exactly what I did Monte except I didn't hold them fully open just used a couple of small wedges under the throttle stops. Might try something a bit thicker next time.

[montmil]

The butterfly valve return springs create the tension problems associated with refitting both cables and getting the top back on without one or both cable ends popping out of position. Use a couple of small, wooden blocks to hold the butterfly valve in the full open position. Tension is removed from the cables and getting all the bits in their correct location is much simplified.

That's pretty much exactly what I did Monte except I didn't hold them fully open just used a couple of small wedges under the throttle stops. Might try something a bit thicker next time.

For those folks still reading this thread, save Barry and I, resist the urge to remove the springs on the butterfly valve's shafts. All you'll get is some cuts on your hands and a difficult refit... unless you remove the Bings. Don't do that!

[georgesgiralt]

And when renovating carbs, do not forget to put new return springs (at least on the choke lever) because sometimes these are so weak the lever does not come fully back....

[Barry]

Going back to the original issue which is wear on the throttle gears there maybe some benefit in fitting the after market lighter springs that are available as besides giving you a lighter throttle action the reduced load on the gears may make them last longer.

[dogshome]

Rather than starting a new thread to search for...

The throttle on my R65 was functional, but very heavy, notchy AND rough!!!

Changing up gear was difficult and cruising meant leaning on the bar to hold it rather than trying to pull back using the wrist all the time. Yuk.

So, cables looked OK but the inners were nasty (typical worn Bowden feeling) and the throttle gears had lumps and bumps (worn off and re-positioned metal). The gears were serviceable since they still looked like gears, so I simply filed off the high spots and re-lubed it all.

Combined with less-fierce springs (from a great shop in California!) the throttle is now (almost) how it should be. No sticking, light and responsive but I can just feel each throttle gear tooth moving to the next. Massively improved though.

Has anyone done something 'random' to replace these gears? The design is good but the materials are rubbish.   

[suecanada]

Less fierce springs available in California??? Gee, I tried lighter springs once and they were too light. May I have the name of that California shop?
I have tried everything mentioned over the years and  I still develop Popeye forearms on a long trip. Doable but could be more comfortable by being a lighter twist. No one has mentioned making sure the wee stop screw behind and below the throttle on the right hand, that is suppose to be a throttle "cruise control", is not turned up too tight to stop light throttle return movement? For those new owners, this screw can remain hidden for years!

[BPT]

Was it the EZ Pull springs you tried before Sue?  The guy that does those has turned the sales over to Ted Porter/Beemershop so maybe that's the California connection?

[Barry]

I was prepared to buy lighter springs but at the time couldn't find them in the UK, so I very carefully stretched the original spings using a spring balance to apply increasing levels of force in measurable increments and to ensure both ended up the same.  This was 10 years ago and has worked fine ever since with a noticeably lighter throttle action. 

Excessively strong springs is typical of German over engineering. I had to replace the throttle spring on my 190e Mercedes for the same reason.

[suecanada]

Was it the EZ Pull springs you tried before Sue?  The guy that does those has turned the sales over to Ted Porter/Beemershop so maybe that's the California connection?

EZ Pull springs...I think so....but they were so weak/light that nothing happened correctly BUT I would trust Ted Porter to get it right so I'll try his website. Thank you!