Crank roller bearing upgrade 4 450

[TheCafeKid]

Lighten up a little would ya? Sheesh.


Now then: I've recently had occasion to rummage in the innards of a GS500 (plain bearing, slightly bigger brother of your GS450 engine) and a GS850 (roller bearing). Both engines are still running perfectly well after many thousands of hard miles, so I must have done something right.

Thinking through the many differences between the cases, the oiling systems, the crankshafts, etc. I don't see a way to change a plain bearing case to rollers or vice-versa.

And, in fact, plain bearings have been proven to be far superior to roller bearings. Millions more cars and motorcycles have been made with plain bearing cranks than roller bearing.

Their only weakness is that plain bearings must have a supply of clean pressurized oil. Rollers can get by with some haphazard splash lubrication.

In other words, I think the problem with plain bearing GS engines lies with the oiling system, not the type of bearings.

I'm not certain what the main problem is exactly, but I suspect that their oiling systems are more prone to clogging and/or starvation than they should be. Better filtration, a higher-capacity oil pump, a higher-capacity oil pan, or perhaps a lower or relocated oil pickup might be worth pursuing.

Some of the oil passages in a GS twin are tiny, and there are some very small oil jets that could easily be clogged by a speck of lint. The oiling systems are also very vulnerable if the oil level gets low.

I also wonder if the oil pump in these engines is marginal -- it's pretty much identical to the pump used in the roller bearing engines (which use little to no oil pressure) and the oil pressure is generated by the restrictions created by the oil jets.

Another thought I had was fitting an oil level sight glass instead of relying on the dip stick. Maybe an old-fashioned clear tube between two fittings, or some way of eyeballing the oil level would encourage owners to keep closer tabs on the oil level. Both of the destroyed GS500 engines we rebuilt came with stories that began "The oil got a little low..."

I have to agree with Brain on this. I always crack on the plain bearing motors, for having plain bearings, but the more ive looked at it the more Ive realized that the fault lies in the design of the oil delivery set up in these plain bearing bikes. Its not much different from that of the rollerbearing bikes, perhaps some tighter ports to increase pressure thruouth the system, and the oil pump IS different, pushing higher pressure faster. As a matter of fact, one of the common mods to the GS1100E (which incidentally have a roller bearing crank and use a low pressure oil system stock) is to pull the oil pump from a 16v 750 motor, which used a plain bearing crank and high pressure system and stick it in your 1100 to ensure that the pressure was increased as to sufficiantly oil the top end, which was a weak spot on those particular machines, (both) especially when they had been hotted up for racing. A "top end oiler" kit was also another common addition to that motor.

[Houdini]

The GS425 has a roller bearing bottom end. If you search this site you may find posts where people have placed a 450 top end on a 425 bottom end...
450FREAK what is it about the 450 that is driving you to a roller bearing crank?
May be other alternatives if we knew your criteria.

[flyingace]

Dude, its not a possible swap. the cranks are two different designs. One rides on shell bearings (yours) one rides on roller bearings (the 8v 550, 8v 750, all 850s, 1000s, and 1100s) the cases are set up differently, its just not something you can pull and replace.

I've been thru the parts fische on these engines, and only 850 and above 8V have roller bearings - not counting 2-stroke and 2-cylinder engines. Now I'm willing to admit I'm wrong if someone can show me different.

[first timer]

i just pulled my 1000 apart and it had roller bearing installed, I am pretty sure all Gs bikes have roller bearings thats why they still drag race them.

[Nessism]

I've been thru the parts fische on these engines, and only 850 and above 8V have roller bearings - not counting 2-stroke and 2-cylinder engines. Now I'm willing to admit I'm wrong if someone can show me different.

First generation GS400/425 both have roller cranks.

First generation GS550 has a roller crank

GS650E (chain drive) has a roller crank

First generation GS750 had a roller crank

GS850/1000/1100 all have roller cranks.

Roller cranks are not better, just different.

[flyingace]

I looked up a 78 750, and it had rollers. Then an 83, and it had plains. I guess I was half right.

[SqDancerLynn1]

Can't be done.. If it was even remotly possible you would have to get a custom made crankshaft. The roller cranks are pressed together after the bearings are installed. Your 450 is a one peice crank The oil pump modification posted for the 1100 roller is not actually changing the pump it is changing the gears to drive the pump faster

[derwood]

Even if possible ( you have 1 piece crank, roller cranks are built up) It wouldn't be an upgrade, although they are cool, there is no advantage to roller cranks.

[mainlymetal]

bearings

If you feel a need for more protection for the crank just go to a motorcycle specific full synthetic oil such as Amsoil or Redline , change your filter each time you change oil and don,t rev the snot out of the engine.It will last a long time , most oriental motors are overbuilt and if left stock will virtually never need work, other than timing chains and valve adjustments.Like most of life you usually get back what you put into something.

[flyingace]

Even if possible ( you have 1 piece crank, roller cranks are built up) It wouldn't be an upgrade, although they are cool, there is no advantage to roller cranks.

Not sure I would go that far. There are advantages and disadvantages. Mainly those big roller bearings spell longevity, even under low or even no oil pressure. They are close to bullet-proof. The disadvantage is they can't be rebuilt easily.