She's BACK! Thanks guys :-)

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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She's BACK! Thanks guys :-)

Postby Cliff-1959 » Mon Jan 23, 2017 8:06 pm

Got the Mod' 20 started again yesterday after the rebuild, and got her fully assembled last night.
I just wanted to say thanks to everyone on here who has helped with advice, encouragement and parts, especially Rob. He gave me lots of advice at the NEC when I thought it was going all wrong, but it turned out that it wasn't :? Many thanks also to Lane Ends engineering in Prescot, who I can't recommend enough. They reground the crank and re-sleeved the barrel at a very reasonable price.
Going to give her a test ride as soon as it's not icy and then change the oil at around 50 miles or so. Any more advice welcome as always!
Cheers again peeps - Lots of knowledge on here....
Plodding along ...

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Re: She's BACK! Thanks guys :-)

Postby ajscomboman » Mon Jan 23, 2017 8:38 pm

Cliff-1959 wrote:Got the Mod' 20 started again yesterday after the rebuild, and got her fully assembled last night.
I just wanted to say thanks to everyone on here who has helped with advice, encouragement and parts, especially Rob. He gave me lots of advice at the NEC when I thought it was going all wrong, but it turned out that it wasn't :? Many thanks also to Lane Ends engineering in Prescot, who I can't recommend enough. They reground the crank and re-sleeved the barrel at a very reasonable price.
Going to give her a test ride as soon as it's not icy and then change the oil at around 50 miles or so. Any more advice welcome as always!
Cheers again peeps - Lots of knowledge on here....


Shhh! Don't let on that I actually might know what I'm talking about or everyone will be asking me tech questions about the twins. :rofl:

Hope it all goes well on the test ride.

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Re: She's BACK! Thanks guys :-)

Postby G15 Roy » Mon Jan 23, 2017 8:53 pm

ajscomboman wrote:
Cliff-1959 wrote:Got the Mod' 20 started again yesterday after the rebuild, and got her fully assembled last night.
I just wanted to say thanks to everyone on here who has helped with advice, encouragement and parts, especially Rob. He gave me lots of advice at the NEC when I thought it was going all wrong, but it turned out that it wasn't :? Many thanks also to Lane Ends engineering in Prescot, who I can't recommend enough. They reground the crank and re-sleeved the barrel at a very reasonable price.
Going to give her a test ride as soon as it's not icy and then change the oil at around 50 miles or so. Any more advice welcome as always!
Cheers again peeps - Lots of knowledge on here....


Shhh! Don't let on that I actually might know what I'm talking about or everyone will be asking me tech questions about the twins. :rofl:

Hope it all goes well on the test ride.


A man of so much knowledge he will,be missed one day. ;)
Roy

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Re: She's BACK! Thanks guys :-)

Postby ajscomboman » Mon Jan 23, 2017 9:00 pm

G15 Roy wrote: A man of so much knowledge he will,be missed one day. ;)


Yeh, one day, but hopefully not for a long time yet!! :beer:

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Re: She's BACK! Thanks guys :-)

Postby Cliff-1959 » Mon Jan 23, 2017 10:00 pm

ajscomboman wrote:
Cliff-1959 wrote:Got the Mod' 20 started again yesterday after the rebuild, and got her fully assembled last night.
I just wanted to say thanks to everyone on here who has helped with advice, encouragement and parts, especially Rob. He gave me lots of advice at the NEC when I thought it was going all wrong, but it turned out that it wasn't :? Many thanks also to Lane Ends engineering in Prescot, who I can't recommend enough. They reground the crank and re-sleeved the barrel at a very reasonable price.
Going to give her a test ride as soon as it's not icy and then change the oil at around 50 miles or so. Any more advice welcome as always!
Cheers again peeps - Lots of knowledge on here....


Shhh! Don't let on that I actually might know what I'm talking about or everyone will be asking me tech questions about the twins. :rofl:

Hope it all goes well on the test ride.


Ha ha, I will keep it to myself
Thanks again.
:beer:
Plodding along ...

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Re: She's BACK! Thanks guys :-)

Postby Cliff-1959 » Mon Jan 23, 2017 10:30 pm

Just to throw the cat in with the pigeons, I have been reading some running-in tips on a site, its mototuneusa.com.
The guy says you have got to run a new or rebuilt engine really hard in the first 20 miles or so to achieve a good ring seal. This is contrary to most advice that I have ever heard, but if you read the stuff on the site, it does makes some sense. Here is a quote:

**********

What's The Best Way To Break-In A New Engine ??
The Short Answer: Run it Hard !

Why ??
Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ...
How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) of combustion pressure ??
Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??

From the actual gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear into
the cylinder surface, to seal the combustion pressure as well as possible.


The Problem With "Easy Break In" ...
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !!

If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again.

Fortunately, most new sportbike owners can't resist the urge to "open it up" once or twice,
which is why more engines don't have this problem !!

An additional factor that you may not have realized, is that the person at the dealership who set up your bike probably blasted your brand new bike pretty hard on the "test run". So, without realizing it, that adrenaline crazed set - up mechanic actually did you a huge favor !!

On the Street:
Warm the engine up completely:
Because of the wind resistance, you don't need to use higher gears like you would on a dyno machine. The main thing is to load the engine by opening the throttle hard in 2nd, 3rd and 4th gear.

Realistically, you won't be able to do full throttle runs even in 2nd gear on most bikes without exceeding 65 mph / 104 kph. The best method is to alternate between short bursts of hard acceleration and deceleration. You don't have to go over 65 mph / 104 kph to properly load the rings. Also, make sure that you're not being followed by another bike or car when you decelerate, most drivers won't expect that you'll suddenly slow down, and we don't want
anyone to get hit from behind !!


**********

There is much more on the site, as well as pictures of pistons from identical race bikes, some of which have been treated gently, and some of them thrashed from new.

What are your thoughts?
Plodding along ...

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Re: She's BACK! Thanks guys :-)

Postby ajscomboman » Tue Jan 24, 2017 6:36 am

That's exactly what Ken De Groome told me about running in my G80CS. Did as told and have had no issues at all with the engine. The carb, well that was another story!

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Re: She's BACK! Thanks guys :-)

Postby Cliff-1959 » Tue Jan 24, 2017 9:52 am

ajscomboman wrote:That's exactly what Ken De Groome told me about running in my G80CS. Did as told and have had no issues at all with the engine. The carb, well that was another story!


Good to know. I will have to disengage Mechanical Sympathy Mode first :shock:
Plodding along ...

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Re: She's BACK! Thanks guys :-)

Postby ajscomboman » Tue Jan 24, 2017 6:56 pm

Cliff, the way Ken summed it was, "Precisely how long do you think my race bike took to bed in after it's rebuild? By the time it got to the bottom of Bray Hill!". That was good enough for me.

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Re: She's BACK! Thanks guys :-)

Postby Cliff-1959 » Thu Feb 23, 2017 10:39 am

Had a few test rides and thankfully all seems well :D

It was a bit smoky at first, but I gave it some beans, (as above,) for the first couple of hundred miles, and now she starts first kick and has very little smoke.

I can't decide if I should risk it on the 2017 TT VMCC parade lap again though, it is a tough climb up the mountain section :shock:

I think from now on I will be a bit over-the-top with oil changes. Having seen the size of some of the oil ways and the poor filtering, I think a few litres of Castrol every few rides is a good investment.
Plodding along ...

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