Forum

[simon]

• Did 70 mph down the motorway the other day on the 350. It will clearly go to 75 and possibly even 80 but with the old sleeve big end I'm far to much of a coward to try it out. The trip I did down to the brother's place 90 odd miles south showed me that the bike was quite capable of cruising at 65 all day barring the fact that with an iron barrel it over heats. Rather than go alloy which is a big change , I wonder if an oil cooler could be introduced somehow in a not too intrusive way or perhaps I have to be happy with 60 and the occasional burst.

[MadMike]

Simon, if by "sleeve big end" you mean shells rather than ball or roller races, then they are more than capable of sustaing the speeds that you are discussing. If you have a car, old or modern, it is almost certain to have shell big end bearings. The factor which affects the bearings is oil. A good supply of clean oil will look after your big ends for you. After all oil is cheap.


You say that at sustained 65mph cruising the engine overheats. Is this something you can quantify? All engines run hot basically because some 80% of the energy created and used is heat energy. The internal combustion engine is only about 20% efficient in reality.


If the engine truly overheated then I would expect some symptoms such as partial or total seizure. Again the oil is doing its work here by lubricating the moving parts and bearing surfaces and also dissipating heat. An oil cooler will not do any harm but needs to be mounted in the airflow, so it becomes difficult to make it unobtrusive. HTH>

[PeteF]

I don't think the oil will be too hot even if the barrel is getting a bit overheated, stick a thermometer in the tank after a blast and you might be surprised.


A high output oil pump conversion might be a good idea if you thrash it often.


If you have an Indian speedo the real speed is probably quite a bit less than indicated. They almost always over-read.


Mike, the big end will be fitted with a floating bush. Some people fit roller big ends but in reality there's not a lot wrong with the bush.

[Adrian]

If you really want to use your 350 for sustained high speed riding (by Bullet standards), you might well need something to give the motor a chance. I had a tuned BSA B40 with an iron barrel that really flew until the piston started melting...


For starters I'd be wanting a steel conrod as well as a nice needle roller big end from our hosts, and definitely an alloy barrel. I don't think they sell oil coolers for Bullets, but Tom Lyons in the USA does, check out AcePerformanceBullets in Yahoo groups.  It would be interesting to see which worked out cheaper, importing the oil cooler or getting an alloy barrel here.


Cheapest option is, as you suggest, to ride it more sedately with the occasional blast to clear your cobwebs. Sounds like it's happy as it is! 


Regards,


A.

[simon]

Thanks Adrian I'll check the US site out. The speedo is a real Smiths Chronometriic so the speed can be relied on. I only discovered last night that RE used shell bearings on the Clipper and Crusader motors. The Bullet has a floating white metal bush with a conrod that can only be removed by splitting the crank. The bush is fine as long as there is plenty of oil but when white metal goes its an all of a sudden thing ( a I remember from a Riley 9 Kestrel that blew up on my in my youth). The overheating is typified by the motor pinking when you pull away after a sustained high speed run. 

[Norm]

 Simon,


   Tim Busby isn't far from you he knows his stuff

[simon]

Googled him and he's down in the Nacky as we hardy southerners refer to the Taranaki Region. It's a good four to five hours away which I know is a trip to the milkbar for you Aussi's but too far for me, however,  I think I'm getting there slowly. Made the clutch slip today which is either an indication of the bhp I'm getting out of this beast or more likely the adjustment I've settled on to compensate for the stupid tin foil clutch cover flex.