Navigation

You are here: Home / Messages / Heavy Twins / Model 7 rods

Model 7 rods

Up to Heavy Twins

Model 7 rods

Posted by tony_cording at March 10. 2018

Hi, 1953 model 7 rod length, I need the centre eye to centre eye measurement to make sure I am using the correct rods. If anyone has this information it would be appreciated.

 

Many thanks - Tony, Vancouver, B.C.

Re: Model 7 rods

Posted by robert_tuck at March 10. 2018

I think they will be the same as later 88 and 99 rods, whatever they are! I have a spare 99 rod somewhere if no one else comes up with it.

Re: Model 7 rods

Posted by tony_cording at March 11. 2018

Previously robert_tuck wrote:

I think they will be the same as later 88 and 99 rods, whatever they are! I have a spare 99 rod somewhere if no one else comes up with it.

 

Hi Robert, thanks for the reply. According to the book the big end on the 500 is 1.500 and on 600/650 1.75, so wouldn't the rod lengths between 88 and 99/ss be different? Perhaps someone could measure an 88 rod length for comparison. On the 7 rods i have mid eye to eye is 6". thanks all.

Re: Model 7 rods

Posted by robert_tuck at March 11. 2018

The 500 and 600 had the same rod  with 1.5 big ends , the 650/750 had 1.75 big ends.Your book is rubbish!!,  Norton did make a few specials for Works racers. There has been talk of perhaps a mystical Nomad with !.75 crank ,But no one has one that I have heard of. No reason you can't have one made, send me 4000 Quid !!. The 600 got its extra capacity from a crank with a bigger throw and bigger Barrel.. The 650 /750 rods wont fit a 7 .  The 650/750 Rods with crank will fit in 7 cases if you weld extra room in there for the bigger crank throw. Are you very brave??. A 99/77 crank /rods/barrel set will fit your cases. Simples!!. Dynamo and alternator cranks are different to each other.

Re: Model 7 rods

Posted by gordon_johnston at March 11. 2018

For the idly curious, a BSA A7 rod will fit an 88 or 99.

Re: Model 7 rods

Posted by robert_tuck at March 11. 2018

He is confused enough as it is Gordon.  Don't mention your 750  model 99.

Re: Model 7 rods

Posted by robert_tuck at March 11. 2018

For the idly curious, are new A7 rods availiable?, are they better than old Norton Rods?.(they do appear to be made from the same forging/stamping).

Re: Model 7 rods

Posted by tony_cording at March 11. 2018

Many thanks for all the input which will be helpful to the Model 7 build. As I have discovered already some of the info in the restoration books we use is suspect. One example is 35 foot pounds torque on crankshaft bolts in the 1974 edition of the Norton Workshop manual by D.J. Rabone, amended in the 1990 edition of the same book to 25 foot pounds. This is also the book which references the 7/88 and 99/650 big end diameters I mentioned. Now I am a wiser man!

Re: Model 7 rods

Posted by robert_tuck at March 11. 2018

Just measured the spare 99 rod. 6inch centers.

Re: Model 7 rods

Posted by tony_cording at March 13. 2018

Hi Robert, many thanks, mine are the correct length.

Re: Model 7 rods

Posted by david_cooper at March 13. 2018

Possibly a good place to remind anyone going inside a Norton twin engine for the first time... Crankshaft bolt torque is listed at 35 lb.ft. in Haynes also... And should be 25 as noted above.

Powered by Ploneboard
This is Brio Diazo Plone Theme