Starfire con rod

[not so speedy]

I am in the process of completely stripping down my newly acquired  1969 Starfire (although engine and frame numbers say it's 1968)

I have now got the con rod off and am confused.
I have read the RR book regarding the different types and mine mostly fits the description of a later rod 70-9911?
It has no small end bush, and has UNF bolts leading me to think it's a later rod and the flywheels have been modified to take it BUT there is no oil hole in the big end.
Both shells  have an oil hole but there's no drilling in the rod.
I am now at a loss as to it's identity and from reading articles, it has to have a hole and this one shouldn't be used.

I take it that I'm now looking to get the later rod, 71-3667, and hope that my flywheels have been modified or I'll have to do so.

Malcolm

[KCF21]

Hi Malcolm,
I was asking myself very similar questions a month or so ago. I was purchasing parts from RR so I asked him about con rods for the C25/B25 and what later parts were available. I Sent him a photo of my original con rod and a later replacement (see photo 2918) Here is his answer:-

The conrod on the right is the 1971 onwards rod and is the strongest type used. If that type of rod has not been fitted to your early crank before you will need to remove metal from the flywheels to provide clearance for it. Check it has the oil hole which it needs for B25 use. If not it is for use in a Triumph 500 which uses the same design of rods in early and late pattern. The timing side rod in the Triumph engine does not have the oil hole.
See also the photographs that he sent to me. As I write this I have a con rod with a local engineering company who are drilling the 1mm hole that is needed to make a Triumph 500 part suitable for the C25 that I am rebuilding.

I hope that this helps because the information helped me,
Kevin

[not so speedy]

Kevin,
Thank you for the reply. I am finding this whole con rod scenario a tad confusing.
I suspect that what I have is a Triumph rod without the hole. How do Triumphs survive not having splash lubrication from a hole?
Obviously I'm looking for the strongest rod (within reason) and have seen some advertised that specifically state that the hole is a stress point and is the most likely point the rod will fail.
I have seen billet rods advertised as the strongest but without a hole, plus expensive rods from MAP that have a groove to provide the splash lubrication again without  a hole.
RR states that the latest Triumph rods are no stronger than the last BSA rod so again why bother with the Triumph rod.
I did wonder about getting mine drilled like you but I'd like to see an original to see exactly how it was done or maybe just try to get the last BSA rod already drilled.

Basically It seems that you make a call which way you're going to go and go for it!

Malcolm

[Pete Gill]

Hi Malcolm
Another option you might consider depending on budget is to buy a new modern alloy one.
I bought a pair of rods for my Triumph twin a couple of years ago from Steve Campbell at thunder engineering in Leicester.
They are excellent quality and you can speak to Steve personally, he is a bike enthusiast and only too willing to help with any questions.
You never know what's happened to a rod that's used, and I take it you'll want to rev the 250cc engine a bit when its run in?? So it might be better to put in a strong new modern alloy one.

https://www.thunderengineering.co.uk/products

Pete

[not so speedy]

Thanks,
That certainly is an idea.
I've seen Steve's work before and as you say excellent quality from an enthusiastic engineer.
The billet rods do look very substantial and at least would be a known quantity compared to the (unknown) rod I have, but again the hole/no hole debate rears it's head.

I'll have a chat with Steve and see what he says.

Malcolm