Forum

[Alan R]

Thanks TIM NZ---- I wasn't sure hence the ?? at the end of that sentence..

[binary]

I am going with the Hitchcock's alloy conrod part number 39231 which is a HDA forging made in England on modern CNC equipment. I will not have to have the crank balanced with this conrod. I am not racing I am just riding around my district on fine days. The crank that is in my older 350 motor, and what is in the motorcycle at the moment was pulled apart and rebuilt with a new floating bush and a new Indian alloy conrod. It was then trued by the same British motorcycle mechanic that I mentioned in a former post. The engine turned out to be incredably smooth with no vibrations to 55 MPH which is the top speed that I ride at. Even at 60 MPH the mirrors stay clear so I have no complaints about his work and the motorcycle has done over 3000 KMs now. I will find out more from Hitchcock's about fitting a roller bearing and then I will let you all on this forum know what I have found out.

[Chris Tindal]

Just a question out of interest binary,......why do you want the roller conversion? a well looked after floating bush will last longer.

[binary]

Hi Chris Tindal. I am going for the roller bearing because there is pressure at the feed oil pump as the pump tries to pump oil through the close fitting floating bush. This crank has no pressure relief valve built into the timing shaft and so the pump disk that the oil plunger works in is lifting off its seat to relieve this over pressure. If I put a roller bearing in place of the floating bush then I will not get this over pressure as the oil will easily pump through this open type of bearing. Redditch motors always had the pressure relief valve in the timing shaft for this reason. I think that the Indians are again fitting the timing shaft relief valve in there newer model motorcycles but I do not know for sure. I am also fitting Hitchcock's timing side pressure relief valve part number 93140. This valve will take care of any over pressure that may occur in the valve rockers and the scavage oil pump will have an easier time of it. Again the Redditch Royal Enfield's built a valve in to control the over pressure at the rockers. This may sound like over kill to others but I am building up the best motor that I can from modern components so that for years to come I will not have to be worrying about my motor being unreliable. I have the 5 speed gearbox which is beautiful to operate and now I am building the perfect motor to match.

[Leon Novello]

Others have gone down this route.

[Colin F]

Leon,can you describe what route that is? Bit confusing as it appears the crankshaft feed has been diverted to the rockers but i must be mistaken.

[PeteF]

Looks like a relief valve on a drilled through quill bolt. Problem with relief valves is if they ever stick open you're sunk.

[binary]

Ok I have the information from Hitchcocks and they say that "to fit the RE13 roller big end the fixed big end bush should be removed and the bush supplied with the RE13 fitted and then honed to size", so it looks like a trip to an engineering shop if you want to fit one of these roller bearings. BW says that in all the years that he has worked on engines with built in pressure relief valves he has never had one stick. The oil feed set up in the picture could not work properly or it has just been faked up for laughs.

[Leon Novello]

Colin: It is thirteen- years ago. I read somewhere that it was a sight glass, feeding into a filter in front of the engine then up to the rockers. Originally in the Australian Royal Enfield Club web site. You can read the posts, but have to sign-in to post a query.

[PeteF]

As I see that picture the quill bolt has been drilled through. If that device on the outside of the timing chest is a relief valve controlling the oil pressure at the quill bolt and discharging into the rocker tunnel I can't see why it wouldn't work.
A pressure gauge plumbed in to the quill bolt certainly works; I've seen it done.