Timing cannot be set accuratly.
Re: Timing cannot be set accuratly.
Hi , Sorry I forgot to add that I had connected the bean can shaft to a drill to test the advance weight as shown in the attached pic. ( The example in the pic is a scrap unit ) Anyway I think I might know the problem .I might of fitted the offset camshaft attachment ring shown in the pic , 180 deg out , oops ! I had punched marks before taking it apart .Just putting all the bits back together .Will report back hopefully with good news , fingers crossed .
- Attachments
-
- Timing unit
- ACE81CB0-A414-49B6-B317-166A65503EC5.jpeg (931.59 KiB) Viewed 1959 times
Giles B
Cheshire
England .
Cheshire
England .
-
Rob Frankham
- Posts: 1214
- Joined: Thu Aug 26, 2010 2:11 pm
- Location: Scotland UK, 20 miles from civilisation up a dead end road!
- Contact:
Re: Timing cannot be set accuratly.
Sorry to say this but that really shouldn't make any difference.
Putting the drive dog on the 'wrong' way round will simply displace the moving parts of the trigger assembly by 180 degrees. As the ignition system is a 'wasted spark' setup,the timing events of the 'other' gap in the shutter (which is also 180 degrees away from the first) will be (in fact must be for the engine to run well) practically identical. By all means check your work but I will be very surprised if it fixes the issue... sorry.
Rob
Putting the drive dog on the 'wrong' way round will simply displace the moving parts of the trigger assembly by 180 degrees. As the ignition system is a 'wasted spark' setup,the timing events of the 'other' gap in the shutter (which is also 180 degrees away from the first) will be (in fact must be for the engine to run well) practically identical. By all means check your work but I will be very surprised if it fixes the issue... sorry.
Rob
Re: Timing cannot be set accuratly.
Hi all. I have’nt come up with a definite reason for my problem seeing the timing marks but i did manage to adjust the can to get the fully advanced Z mark in the correct position , but the Z showing on low revs at idle is still perplexing . I did check the timing gun and its fine . The bike is on the road now and runs fine plus the plugs are a good colour but i need to be 100% sure .Thanks for the offer of loaning your bean can Rob .I have a newer bean can with a suspect hall transistor so i am currently in the process of fitting a new transistor ordered from FlatRacer .I ordered 2 new advance springs from Motoworks and wanted any thoughts before fitting them as they are much shorter than the old ones . I do realise that they can wear and stretch in time . In the pic shorter the new springs width are the same and they have the same amount of coils and obviously i can feel much more stretching resistance .I thought quite some time ago I had read the the MW springs were too strong but cannot find the post again .Any thoughts folks?
- Attachments
-
- 3AB251BC-77C5-4D53-AD02-6AC0331804E9.jpeg (1002.55 KiB) Viewed 1856 times
Giles B
Cheshire
England .
Cheshire
England .
Re: Timing cannot be set accuratly.
Those old springs are obviously totally shot.
New springs of this type have no space between the coils when new.
The old ones might appear to pull the weights in on the bench, but they just aren't strong enough to pull the weights in with the engine spinning. The rule of thumb is to replace them if there's even a slight gap between the coils when unhooked.
Once the new ones are fitted, timing will pull back to 'S' when idling.
With worn springs the timing will be too advanced below 3000rpm.
You've already confirmed that with your timing light.
Some common symptoms often caused by different degrees of spring wear include:
*Won't drop to idle speed.
*Takes too long to drop to idle speed.
*Starter sometimes feels like it's weak, doesn't have it's usual 'kick'.
*Pinging immediately when accelerating from a dead stop.
*Timing mark doesn't move smoothly from 'S' to 'F' (or'Z').
New springs of this type have no space between the coils when new.
The old ones might appear to pull the weights in on the bench, but they just aren't strong enough to pull the weights in with the engine spinning. The rule of thumb is to replace them if there's even a slight gap between the coils when unhooked.
Once the new ones are fitted, timing will pull back to 'S' when idling.
With worn springs the timing will be too advanced below 3000rpm.
You've already confirmed that with your timing light.
Some common symptoms often caused by different degrees of spring wear include:
*Won't drop to idle speed.
*Takes too long to drop to idle speed.
*Starter sometimes feels like it's weak, doesn't have it's usual 'kick'.
*Pinging immediately when accelerating from a dead stop.
*Timing mark doesn't move smoothly from 'S' to 'F' (or'Z').
Mechanic from Hell
"I remember every raging second of it...
My bike was on fire, the road was on fire, and I was on fire.
It was the best ride ever!"
"I remember every raging second of it...
My bike was on fire, the road was on fire, and I was on fire.
It was the best ride ever!"
Re: Timing cannot be set accuratly.
I’ve owned an r65, r100r, and a r100 mystic over the last 35 years, and had the same bean can advance issues with all of them.
The mechanical advance is subject to sticking and causing run away at idle(usually when engine is very hot)
I decided to replace the bean can with the Alpha electric advance replacement.
It was bit pricey, however solved the problems with the dreaded bean can….it was a easy install and makes idle much more stable.
Just something to think about.
The mechanical advance is subject to sticking and causing run away at idle(usually when engine is very hot)
I decided to replace the bean can with the Alpha electric advance replacement.
It was bit pricey, however solved the problems with the dreaded bean can….it was a easy install and makes idle much more stable.
Just something to think about.
Re: Timing cannot be set accuratly.
I’ve owned an r65, r100r, and a r100 mystic over the last 35 years, and had the same bean can advance issues with all of them.
The mechanical advance is subject to sticking and causing run away at idle(usually when engine is very hot)
I decided to replace the bean can with the Alpha electric advance replacement.
It was bit pricey, however solved the problems with the dreaded bean can….it was a easy install and makes idle much more stable.
Just something to think about.
The mechanical advance is subject to sticking and causing run away at idle(usually when engine is very hot)
I decided to replace the bean can with the Alpha electric advance replacement.
It was bit pricey, however solved the problems with the dreaded bean can….it was a easy install and makes idle much more stable.
Just something to think about.
Re: Timing cannot be set accuratly.
Giles B wrote: ↑Mon May 08, 2023 10:29 am .I ordered 2 new advance springs from Motoworks and wanted any thoughts before fitting them as they are much shorter than the old ones . I do realise that they can wear and stretch in time . In the pic shorter the new springs width are the same and they have the same amount of coils and obviously i can feel much more stretching resistance .I thought quite some time ago I had read the the MW springs were too strong but cannot find the post again .Any thoughts folks?
Giles,
Your suspicions about those new springs seem to be correct. I've just read a post on BM bikes that suggests the Motorworks supplied springs are too strong resulting in advance not starting until 2400 RPM and finishing at 3500 RPM.
The correct springs should start to advance at 1550 rpm and finish at 3000 rpm
https://www.bmbikes.org.uk/viewtopic.ph ... 6&start=50
barry
Cheshire
England
Cheshire
England
Re: Timing cannot be set accuratly.
Thanks for confirming that Barry, I was sure I had read it somewhere. I do have 2 pairs of old springs which I will check their lengths. Otherwise unless there is another source for closer spec springs I will probably stick with the newer springs if the don’t cause any engine problems. When riding I can feel a noticeable surge in acceleration at a point in the lower revs not felt before ,but as my g/s does not have a tacho it’s not possible to measure where it appears.
Giles B
Cheshire
England .
Cheshire
England .