R&R conrods

Hi Jan. No experience of R&R rods but I fitted a pair of Thunder Engineering rods to my Dommie 99 and they are beautifully made items. They also weighed exactly the same as one another so are well machined and matched.

I had the crank rebalanced just to be safe. One thing I found was that the new rods were a bit meatier than the originals so I needed to notch out the bottom of the cylinders front and back with a Dremel grind stone. I also had to grind (also with a Dremel) a couple high spots off the inside of the crankcases to ensure there was good clearance when the crankshaft rotated.

I have no connection with Thunder Engineering apart from being a satisfied customer.

Good luck

Regards

Tony

I also have some Thunder Race con-rods, as they were especially made for me from a pattern that i supplied. They are such a well made rod for Norton twins. They will also make any con-rods to your pattern. The late Mick Hemmings used to supply America made con-rods and i have used these in one of my own Atlas engines. 

For a general road bike I like to see steel big end caps not aluminium ones.

I get it that the R&R ones are a little cheaper than standard, but some of the text on their website suggests the short term life of their rods and is dismissive about these being a readily replaceable consumable item.

To me, a conrod doesn’t fall in to that category.

I would replace shells and bolts, then polish to a mirror finish, but expect the conrods themselves to last.

The originals are so good, the only alternative I’d consider would be a Carrillo steel rod if I was building a hotter engine.

...just my opinion.

Mick Hemmings bored out my 850 barrels to about 900cc to suit a pair of Cosworth pistons I had bought elsewhwere. As their gudgeon pins were larger, he suggested that, on boring out the small end eyes in the Norton rods, to bore them eccentric, ie shorten the centre lines, so as to keep as much meat on top of the rods as possible. He recommended Carillo rods because "they're like AIDS- they last forever".

A stillborn project, so I never exploited either avenue.

I also fitted Thunder Engineering conrods.  Agreed, they are finely machined.  They are a little heavier, but the extra is less than fitting heavier pistons.  I didn't get my crank re=balanced, and have had no significant vibration issue.  I did not need to enlarge the crank case clearances.  They just went straight in.

BTW, I fitted replacement rods because a previous owner wrecked the originals.  -0.010" shells on a std crank do not make for happiness (he actually confessed to that)....  the big end eyes were oval with bent rod bolts when I pulled it apart.  New rods the only possible solution.

Ditto, just a satisfied customer.

Paul