Mercury is Finished for now...

NorLuck · Dec 31, 2022

Hi guys,

Mercury is finished for now.. All the original bits are in storage for the foreseeable future. A few issues still needing sorting.

I haven't installed the speedo/tacho (lazy is all). I don't like how far out the headlamp brackets are (need to make custom ones I guess). The seat isn't bolted down, I need to get my welder to weld some tabs on the frame or I need to make some type of base pan that the seat clips into. The tank is also not strapped in the way I'd like, I need one of those cross bars welded in.

Questions:

1) I can't seem to get the leverage position right on the gear change, it won't select gears (suggestions?)

2) I don't know if it's my imagination but the carb seems to be getting VERY hot, hotter than I originally thought it got and the gas tank seems to be pretty warm too (maybe because it's now alloy instead of steel?) I'm just worried that maybe the tri-spark is setup slightly wrong and thus the engine is overheating? Or maybe it's all ok and normal haha I have been pre-occupied with another bike and haven't really bothered riding the Mercury.

Anyway here it is for now:

robs ss · Dec 31, 2022

NorLuck said:
Hi guys,

Mercury is finished for now.. All the original bits are in storage for the foreseeable future. A few issues still needing sorting.

I haven't installed the speedo/tacho (lazy is all). I don't like how far out the headlamp brackets are (need to make custom ones I guess). The seat isn't bolted down, I need to get my welder to weld some tabs on the frame or I need to make some type of base pan that the seat clips into. The tank is also not strapped in the way I'd like, I need one of those cross bars welded in.

Questions:

1) I can't seem to get the leverage position right on the gear change, it won't select gears (suggestions?)

2) I don't know if it's my imagination but the carb seems to be getting VERY hot, hotter than I originally thought it got and the gas tank seems to be pretty warm too (maybe because it's now alloy instead of steel?) I'm just worried that maybe the tri-spark is setup slightly wrong and thus the engine is overheating? Or maybe it's all ok and normal haha I have been pre-occupied with another bike and haven't really bothered riding the Mercury.

Anyway here it is for now:

On question 2 - you don't appear to have any heat insulation to stop it getting hot. See below - RGM have them in a number of sizes (other suppliers will too I suppose)
Cheers

CARB HEAT INSULATING WASHERS, DOMINATOR 1 1/2" CENTRES

D12/984

www.rgmnorton.co.uk

texasSlick · Dec 31, 2022

Re Question 1
Do you have the spring on the Rachel pawl on properly? IIRC, the long straight side should be on top.
Consult your manual for proper way.

Slick

NorLuck · Jan 1, 2023

robs ss said:
On question 2 - you don't appear to have any heat insulation to stop it getting hot. See below - RGM have them in a number of sizes (other suppliers will too I suppose)
Cheers

CARB HEAT INSULATING WASHERS, DOMINATOR 1 1/2" CENTRES

D12/984

www.rgmnorton.co.uk

Have one of these between the carb and the manifold.

robs ss · Jan 1, 2023

NorLuck said:
Have one of these between the carb and the manifold.

Couldn't see that 👍
Could be worth installing them between the head and manifold too if you're having temperature issues.
Cheers

Fast Eddie · Jan 1, 2023

Incorrect ign timing, or carb settings, will cause excess heat.

NorLuck · Jan 1, 2023

texasSlick said:
Re Question 1
Do you have the spring on the Rachel pawl on properly? IIRC, the long straight side should be on top.
Consult your manual for proper way.

Slick

I fiddled with it quite a bit still not ideal.

Fast Eddie said:
Incorrect ign timing, or carb settings, will cause excess heat.

Yeah was thinking it's the carb but wanted to rule out incorrect timing.

baz · Jan 1, 2023

Try turning your headlamp ears up the other way to see if you prefer the look
If not then make new shorter ones but keep the rubber mounts
Did your gear change work ok before fitting the rear sets?
Have you ridden it with the rear sets yet?
Those exhaust hangers will not be lasting very long
You'd do better getting a pair made that triangulate the fitting and you may be able to pull them up a little

baz · Jan 1, 2023

Be careful of over tickling that carb on a hot day with a short bellmouth

NorLuck · Jan 1, 2023

baz said:
Try turning your headlamp ears up the other way to see if you prefer the look
If not then make new shorter ones but keep the rubber mounts
Did your gear change work ok before fitting the rear sets?
Have you ridden it with the rear sets yet?
Those exhaust hangers will not be lasting very long
You'd do better getting a pair made that triangulate the fitting and you may be able to pull them up a little

Yeah tried it both ways, still a bit funny. Partly due to the fact that the headlamp is a pancake style shell.

Gear changed worked fine before. It’s hard to change gears now as the leverage seems wrong. I haven’t used the rearset yet.

Exhaust hanger was original to the Dunstall mufflers (how I bought the bike), but I’m actually getting new small mufflers basically short megas but with noise control.

Changing out shocks and actually quite a lot of other things but thought I’d go out and about on it a bit before it gets disassembled again.

NorLuck · Jan 1, 2023

baz said:
Be careful of over tickling that carb on a hot day with a short bellmouth

I have an air filter that I’ll be putting on this bike.
It’s a half feeble kick starter though. Don’t even really have to tickle the carb. Just press and when I hear the fuel stop.

NorLuck · Jan 1, 2023

Need a timing gun and someone who knows how to use it

@gortnipper

Schwany · Jan 1, 2023

It's an air cooled antique twin. It may feel hot idling, especially if the motor is fresh. Timing has to be more than a few degrees out to cause overheating.

Not a popular solution, but it works: You can static time the old motor and be in a very safe ignition timing window. TriSpark with the Red LED makes it a painless exercise. I've outlined how to do it the old school way and verified it all with a degree wheel. I don't use a timing light, since it is very inconvenient and difficult to do on my model Norton with only two arms. My bike is easy to start and does not suffer for lack of top end power. Anyway, doing static timing this way is nothing new. It is however seldom mentioned.

Doing it like it was done in the olden days is totally repeatable for accuracy. Try it before dismissing it, but only if you can't get help to do it with a light. I work alone and prefer working alone, so figure out how to do everything on my own.

Here is a link: Static timing

Stock Amal jetting will probably be a little lean with a velocity stack.

seanalex · Jan 1, 2023

Regarding the gearchanging being difficult. I've had similar issue before. I found that if the arm linkage is super taught it won't be able to ratchet the pawl up and down. Obvs hard to tell in the photo how tight that arm is.

NorLuck · Jan 1, 2023

seanalex said:
Regarding the gearchanging being difficult. I've had similar issue before. I found that if the arm linkage is super taught it won't be able to ratchet the pawl up and down. Obvs hard to tell in the photo how tight that arm is.

Thanks for the tip. I’ll try adjusting it!

NorLuck · Jan 1, 2023

Schwany said:
It's an air cooled antique twin. It may feel hot idling, especially if the motor is fresh. Timing has to be more than a few degrees out to cause overheating.

Not a popular solution, but it works: You can static time the old motor and be in a very safe ignition timing window. TriSpark with the Red LED makes it a painless exercise. I've outlined how to do it the old school way and verified it all with a degree wheel. I don't use a timing light, since it is very inconvenient and difficult to do on my model Norton with only two arms. My bike is easy to start and does not suffer for lack of top end power. Anyway, doing static timing this way is nothing new. It is however seldom mentioned.

Doing it like it was done in the olden days is totally repeatable for accuracy. Try it before dismissing it, but only if you can't get help to do it with a light. I work alone and prefer working alone, so figure out how to do everything on my own.

Here is a link: Static timing

Stock Amal jetting will probably be a little lean with a velocity stack.

Need the tool, this is awesome advice!

Fast Eddie · Jan 2, 2023

You need to make make sure those clevis joints are not fouling inside when you operate the lever.

It also looks to me like you need to play around with pedal position and lever angles.

The gearbox lever looks quite short to me. Which makes me think the clevis pin could be fouling on the gearbox outer cover.

robs ss · Jan 2, 2023

You have not stated what you actually did with the gearbox (unless on another thread).
Common shifting problems come from poorly installed hair-spring (@texasSlick referred to this in #3)
You could do worse than check you have followed the advice from tech section: Old Britts - Assembling the Commando gearbox particularly pages 14 & 15

NorLuck · Jan 2, 2023

With the stock style lever and peg it works perfectly. The leverage is just somehow bad with this rearset. I think I need to play around a bit with the slight length adjustment and the angles like mentioned. Gonna do that tomorrow.

baz · Jan 2, 2023

NorLuck said:
With the stock style lever and peg it works perfectly. The leverage is just somehow bad with this rearset. I think I need to play around a bit with the slight length adjustment and the angles like mentioned. Gonna do that tomorrow.

The gearbox lever looks a bit short to me