Molnar Precision Ltd TGA Commando Parts

RichMPL

Joined
Apr 14, 2022
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Hi All

As some of you may know, we have been making parts for Norton Twins for the last few years, and whilst my knowledge of Norton Twins is limited, my old man has been involved with them since before he was my age!

We are now at a point where we have Crankcases and Alloy Barrels in stock. We have also recently released our first batch of all Steel Cranks & Flywheels, available as a full set or just as the flywheels.

We are Working with John Snead/STS not only bringing 750/850 heads but also 1000cc heads.

Also I am working on refining the Piper 8 valve head so then it can be a direct bolt on to an 850cc motor.

I’d just like to direct you all to our website to have a look, and give us feedback, after all we want to make sure we are making what you guys need, and we are meeting your expectations in terms of quality!

So please have a look at: https://www.tga.co.uk/shop/norton-twin-engine/
And let me know your thoughts. I’ll do my best to answer any questions.
 
Thankyou, have this bookmarked.
Andy and I met in California…1983. He bent a pushrod on a Domminator on Ebbits Pass during some “enthusiastic riding”. Northern California Norton Owners Club rally at Pinecrest.
Here is some nostalgia for you. My black ‘73 750 next to him.
Molnar Precision Ltd TGA Commando Parts
 
RichMPL said:
Hi All

As some of you may know, we have been making parts for Norton Twins for the last few years, and whilst my knowledge of Norton Twins is limited, my old man has been involved with them since before he was my age!

We are now at a point where we have Crankcases and Alloy Barrels in stock. We have also recently released our first batch of all Steel Cranks & Flywheels, available as a full set or just as the flywheels.

We are Working with John Snead/STS not only bringing 750/850 heads but also 1000cc heads.

Also I am working on refining the Piper 8 valve head so then it can be a direct bolt on to an 850cc motor.

I’d just like to direct you all to our website to have a look, and give us feedback, after all we want to make sure we are making what you guys need, and we are meeting your expectations in terms of quality!

So please have a look at: https://www.tga.co.uk/shop/norton-twin-engine/
And let me know your thoughts. I’ll do my best to answer any questions.
Click to expand...
Nice one Rich, keep that good stuff coming !!
 
Oh dear! I’ve just read through the list of stainless stuff, I’m sure my card will soon take a hit. :eek: I’ve bookmarked the site details.
 
RichMPL said:
We are now at a point where we have Crankcases and Alloy Barrels in stock. We have also recently released our first batch of all Steel Cranks & Flywheels, available as a full set or just as the flywheels.

So please have a look at: https://www.tga.co.uk/shop/norton-twin-engine/
And let me know your thoughts. I’ll do my best to answer any questions.
Click to expand...
Nice offerings. The crankshafts you make will not fit the Mk3 model, and your advert should be corrected on this account. There were numerous changes, and I doubt your flywheel, if purchased separately, will fit.
Do you envision producing a variant for the Mk3?

- Knut
 
mdt-son said:
Nice offerings. The crankshafts you make will not fit the Mk3 model, and your advert should be corrected on this account. There were numerous changes, and I doubt your flywheel, if purchased separately, will fit.
Do you envision producing a variant for the Mk3?

- Knut
Click to expand...


RichMPL​

Last seen May 31, 2022

Probably better to P.M. him.
 
RichMPL said:
Hi All

As some of you may know, we have been making parts for Norton Twins for the last few years, and whilst my knowledge of Norton Twins is limited, my old man has been involved with them since before he was my age!

We are now at a point where we have Crankcases and Alloy Barrels in stock. We have also recently released our first batch of all Steel Cranks & Flywheels, available as a full set or just as the flywheels.

We are Working with John Snead/STS not only bringing 750/850 heads but also 1000cc heads.

Also I am working on refining the Piper 8 valve head so then it can be a direct bolt on to an 850cc motor.

I’d just like to direct you all to our website to have a look, and give us feedback, after all we want to make sure we are making what you guys need, and we are meeting your expectations in terms of quality!

So please have a look at: https://www.tga.co.uk/shop/norton-twin-engine/
And let me know your thoughts. I’ll do my best to answer any questions.
Click to expand...
What a mistake to open your web page... i can see some hard earned departing to Preston pretty soon
 
The MK3 cranks are already beefed up a bit from the earlier cranks, as are the MK3 cases. Perhaps this is why Molnar hasn't come up with a strengthened MK3 crank.

Glen
 
worntorn said:
The MK3 cranks are already beefed up a bit from the earlier cranks, as are the MK3 cases. Perhaps this is why Molnar hasn't come up with a strengthened MK3 crank.

Glen
Click to expand...

I broke my last 3 Mk3 cranks in one season, even though they had steel flywheels.

Also, I'm not convinced that the Mk3 cases are any stronger, wider to accomodate the shaft, yes, but not thicker
 
Seeley920 said:
I broke my last 3 Mk3 cranks in one season, even though they had steel flywheels.

Also, I'm not convinced that the Mk3 cases are any stronger, wider to accomodate the shaft, yes, but not thicker
Click to expand...
Where did they break (ie what failed… not which circuit you were on) ??
 
Fast Eddie said:
Where did they break (ie what failed… not which circuit you were on) ??
Click to expand...

2 across the big end journal, one split lengthways on the timing side cheek, from the grub screw at the top (for the oil drilling) , all the way down to the main bearing journal
 
Seeley920 said:
2 across the big end journal, one split lengthways on the timing side cheek, from the grub screw at the top (for the oil drilling) , all the way down to the main bearing journal
Click to expand...
Sounds nasty and abrupt. Did you break any of your personal body parts?

I don't race but that kind of thing goes through my mind way too often when I'm out riding an old Norton and that is just on the street. I do like to ring its neck, so if it let go nobody to blame but myself.
 
Seeley920 said:
I broke my last 3 Mk3 cranks in one season, even though they had steel flywheels.

Also, I'm not convinced that the Mk3 cases are any stronger, wider to accomodate the shaft, yes, but not thicker
Click to expand...
Yikes, this is a good argument for staying with the lower rpm power band of the stock engine!
As far as I know, the only extra strength items on the MK3 crank are the bolts. There must have been some issues with the smaller bolts on the pre MK3 cranks.
After reading your info and lots of past similar posts, I wouldn't trust any of the production parts for racing or any sustained high rpm use.

Somewhere in the factory notes there is reference to some strengthening that was added when the MK3 cases were designed.
The goal was a slightly more durable road bike, not a race bike, so they seem to have achieved their goal.

Glen
 
Wrong balance factor might be a reason for broken cranks. The Maney steel flywheel is very interesting. However if it is a replacement part for a standard cranks and has the original stupid 54% balance factor, it is of no use to me. The simple fact of the matter is, if you rev a normal Commando past 7000 RPM, you are likely to crack the crankcases. Every Triumph 650 ever created could be revved to 8000 RPM without destroying itself. With a Nourish crank and Puma cases, Triumph 650s were even better.
When a motor runs with very low vibration at 7000 RPM, it must be doing less damage to itself, than one which is jumping around. If the motor shakes at low revs, the internal loads are less them when it vibrates at high revs.
I appreciate that an unmodified Commando is a very good ride, but it does not pay to fang one.
 
Seeley920 said:
2 across the big end journal, one split lengthways on the timing side cheek, from the grub screw at the top (for the oil drilling) , all the way down to the main bearing journal
Click to expand...
I've been there as well. Forty years ago my 650ss broke its crank across a big end & only the rod held it together, saving the cases. Also, on my 850 MK2a, which snapped on the DS shaft, meaning I very nearly had a serious accident. I don't think the bolts have ever been a problem though, whether 5/16" or 3/8".
 
Seeley920 said:
2 across the big end journal, one split lengthways on the timing side cheek, from the grub screw at the top (for the oil drilling) , all the way down to the main bearing journal
Click to expand...
What revs were you pulling and with what balance factor ? With my bike, I use a close ratio gearbox with very high overall gearing. If you get an improvement in torque, you often do not know you have it until you raise the overall gearing. If you are running under-geared, you might be revving too high. With the heavy crank, lowering the gearing usually does not give you better acceleration, because the crank always tends to spin-up at the same rate. However I no longer believe in light cranks. With the heavy crank, you lose less revs on every up-change. And coming down through the gears is more controlled.
With the Commando engine, throttle response is greatly affected by jetting. I do not know how anybody can get it right when they are using petrol as the fuel. Even with methanol, the difference between fast and slow is almost nothing in terms of needle jet size, and needle shape. When using methanol, the jets usually flow at about twice the rate, when compared with petrol jets. So changes in jet size is half as critical. When you are jetted slightly too rich, it is very difficult to detect the loss in performance. But when you get it right, you know it.
 
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