Hitchcocks Forum

Hello everyone. Since the floating bush big end bearing seems prone to failure, might there be any benefit in dosing the engine oil with Molyslip, especially if long periods of fast cruising are anticipated? Just a thought.
Geoffers.

Hi GEOFFERS }----------- here's their site--------have a look http://www.molyslip.co.uk/about/ -------- The theory is sound but would it work for us is the question. Anybody out there tried it at all ??

Hi Geoffers, the floating bush big end has been used for many many years and was never prone to failure, if failures are now occurring then it is due to lack of oil change at the correct time, the wrong grade/type of oil or poor manufacture., IMHO.

What made me think of this was that many years ago I worked at Chrysler UK , grinding and regrinding crankshafts. When Hunter cranks (made from Meehanite cast iron) came in for reconditioning, you could always spot the ones where Molyslip had been used by the coloration it left on the bearing journals. These ones often had no discernible wear and were frequently still within their original manufacturing tolerance (0.0004") on diameter. If the crank was still perfectly straight we just lightly lapped the bearings and job done! Thats what makes me think it might prolong engine life, also might be good for those plain bearing bushes in the gearbox. Definitely NOT the primary drive though!! Got to have a go at my 350 gearbox soon so I may give it a try.
Geoffers.

Hi Geoffers
I have been using Molyslip in my 2005 500 Classic since new. I have also been using it in my BSA lightning for 30 years plus. No bigend problems in either and I used to rag the BSA. I am easier on it these days. Having said this the engines may well have been fine without the Molyslip.
Regards
Edward

When we say "prone to failure", I understand that a big-end will last at best about 40,000 miles. If this is normal then is it a problem? Like say an airfilter is changed after 5000 miles or so, it's not a failure.

I treated my 2001 Bullet 500 quite gently and got about 40,000 miles on the first big-end, no-one has said that they have got any more than that (so far). I'll be interested to know what exactly is normal and whether the rollwer big-end lasts any longer.

Wasn't there a problem with Molyslip centrifuging out and blocking the oil ways in the crankshaft? ...(more likely with twin engines that had sludge traps)...I'm not saying this IS so....I just read something about this once....not sure if it can happen. In reply to Chris, 40,000 miles would be considered an excellent big-end life, no question about that. BUT...how many Indian Bikes ever get anywhere near that mileage from the bush big end? I think I can remember reading on here that "Norm" was having to replace Indian big-ends in only a couple of thousand miles and he wouldn't be the only one. You have set your engine up very accurately and made sure you have good oil pressure and the OPRV is working and not releasing oil pressure at a low pressure or constantly leaking. You have also aligned your crankshaft accurately and set up the big end clearances accurately too, hopefully you will get a very long life from them. Alpha bearings told me that the biggest problem with Indian cranks was there alignment.

We just stripped down a Bullet Five speed Gear Box recently that had well over 30.000 Miles on it for conversion to right foot change. Whilst it was apart we checked and measured all parts to see if anything else needed replacing and was very surprised to find there was no wear detectable not even on the gears dogs nothing all were in good usable condition still. The owner has always used Fuchs Synthetic 75/90 Gear Oil in the box. Makes me think this would be a better bet in the engine as well instead of using any additives just use a good quality synthetic Oil What do others think.

P/s Sorry that should read - The owner has always used Fuchs Synthetic 80/90 Gear Oil in the box.
Sorry I don't want to start the old oil argument again just wondering If anyone has used synthetic in the engine for a long period and noticed any Improvement in Wear when stripping down.

Thanks for all the comments guys.
Geoffers.