LCGB Forums

After a 107 rod ror a sil crank.
What's good and what to avoid.
About 20bhp 15 lbft

AF do various rods but this one should be ok, but check the width as indian rods are a tad over 15mm wide were as most others are 16mm

http://www.afrayspeed.co.uk/index.php?p ... tributeID=

Thanks ^^^^ any others

Anyone heard of a company called Long, made in Japan any good?

You won't get a Long made rod at 107, nearest would be 110 so packer required.

I'd go with the one Scotty has recommended - used a few of these no issue

As Gary said Long are Japanese and manufacture RD/Yam rods @ 110/115mm which can of coarse be fitted with modifications to crank webs, and as highlighted a packer is usually required for 39mm compression height pistons

Sorry I've confused things
The long rod is one I already have and is 115
Just wondering if it a good un for another project.
Are standard sil rods available
Been up to the job for 10k miles till the bearing failed.

Don't use the SIL Rod!

Apart from being ugly as sin what's the issue?
On the old forum I asked if anyone had any first hand experience of them filing and only had one report not first hand of one failing in a 28 bhp engine.
Had a think and I have a twisted alpha crank (Don't we all) those rods are good, no?

SIL crank webs are usable but I wouldn't use a SIL rod and bearings even in a stock tuned motor. Just not good enough.

Are you planning on removing the 115 rod to fit a SIL 107 rod? I've got a load of SIL 107 rods that I've had removed from new SIL cranks if you want one. I'm just summising but maybe their poor quality throws them out of balance adding to the woes of a poor quality big end bearing. Maybe both big and small end could be linished to balance them better. Good quality 110 rods are not expensive, probably more cost in the labour involved but makes far more sense to use a 110 rod with a 3mm packer than to risk using a Sil rod.

thanks corrodo
ill take you up on the offer,
I,m a bit of a champion for what works over often un proven. ive never suffered any issue with sil cranks once the bearing has been changed for a jap one, on this bike it had just had a full engine rebuild after being stood since belguim euro. all seemed fine on checking but in Belgium yhis year the big end bearing seized so I could possibly have fitted a sil crank with the Indian bearing still in or it had picked up a bit of pitting being left so long. I wouldn't want to risk the old rod or pin.
also its going in a AFrayspeed Stype Sil . which ive tried to keep as original as possible.
the top end is a ts1 200 with a 34mm amal , so not mega power.

If I were you I'd put use the old type AF race rod kit in the SIL webs as a minimun. Then you can forget about it.
Don't use the SIL rod..... Even with a decent bearing in a TS.....
I'm a massive advocate of SIL webs with the right rod.
I've used plently of the AF rods in SIL webs with no issues. They pan out very cheap and bullit proof overall.

Quick straw poll, any one reading this had a sil rod fail?

Oh yes.
Sometimes..... it's just an overheating big end failure.
Other times........... the Rod snaps.....and the consequential damage is usually untenable when this happens.
Its easy to work out..... If SIL Rods were the dogs bolloxs, the market would dictate that we pay top dollar irrespective of what nationality made it.
By fitting a TS1 top end, you are in effect doubling the power output over stock. It simply doesn't make sense to use a critical component that is under engineered by design and material for the task.
In a stock engine, built to a good standard and properly lubricated, it would give good service but i wouldn't advocate using them above this level.
BTW. I would be quite pleased with 10K miles from a crank the way I ride em and would happily replace with like for like rather than mess with the format.

As mention SIL webs are good in that they offer a much tighter pin/ tonnage on the press, they don't look to pretty but are good webs, the pins are often slightly larger than say a 22mm Jap or Italian equivalent and as a result the big end bearing/rod can be a little to tight. I've also got a load of SIL rods, many unused, the scrap mans taken a few to, I've seen them crack/little end eye snap off and bearing surface come away, why would you take a chance?

Fast n Furious wrote:BTW. I would be quite pleased with 10K miles from a crank the way I ride em and would happily replace with like for like rather than mess with the format.

The sil rod would be like for like.

Yes, in a new sil engine many years ago after only a couple of hundred miles

Rod is still fine but bearings seized 6000 miles as a ts1 200
The bike was built by AF from new as ts1 in 88

Scooterlam wrote:Rod is still fine but bearings seized 6000 miles as a ts1 200
The bike was built by AF from new as ts1 in 88

The rod may still look fine, but you have to question why the needle bearing failed, surely?

Presuming it was of good quality, then either lubrication (oil type & ratio/sufficiently slotted rod oilways) or the rod bore will have allowed the rollers to skid & overheat. The bore can be checked with the right equipment, but the metallurgy & hardness of the bore still remains questionable. How much would that whole process in a suitably equipped engineering workshop cost?

In asking for advice, you have received good recommendations which I would endorse & I'm uncertain why you appear to be playing Devil's Avocate. Grampian motors have online details of the rods that they supply & I have used their products from anything between 105 & 118 mm with absolutely no problems.

Even on a standard engine rebuild, I would never use an Indian conrod, any head gaskets whatsoever (yet always achieve a 1 mm squish) or fit that Indian duplex 3/8” stretchy cr@p they sell, laughably called ‘chain’

Scooterlam wrote:

Fast n Furious wrote:BTW. I would be quite pleased with 10K miles from a crank the way I ride em and would happily replace with like for like rather than mess with the format.

The sil rod would be like for like.

Aye.
I mean't like for like in a stock engine.