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Author Topic: New Bullet Engine  (Read 4613 times)

Kevin Mahoney

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Re: New Bullet Engine
« Reply #15 on: December 01, 2007, 07:51:07 PM »
One good thing about the new engine is that it should be the platform that Royal Enfield will use for several years. This allows us and others time and the incentive to develop aftermarket parts such as exhausts, performance enhancements etc.

HRAB

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Re: New Bullet Engine
« Reply #16 on: December 01, 2007, 10:51:21 PM »
The question was asked about the difference between dry and wet sump.
The dry sump engine allows the crank to spin in air instead of in oil resulting in very slightly less drag or friction.
The wet sump engine will have the oil in the crank case near the crank but usually the engine is designed to hold the oil, especially when running, below the swing of the crank.( Like 99.99% of the car engines out there with "oil Pans") So in most engines there is little difference.

The Unit Engine often will have less internal power loss when compared to an engine with separate transmission/Engine configuration. This is usually due to gear drive vs primary chain drive. The unit construction also lends itself to a larger volume of oil in which the unit can operate.

I haven't seen the new unit yet, but I suspect it will be split horizontally instead of vertically. This may result in a huge disapointment to some of us traditionalists...not seeing the reasuring oil spot on the grage floor!  ;)
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stipa

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Re: New Bullet Engine
« Reply #17 on: December 02, 2007, 07:48:49 AM »
I guess I have a hard time envisioning a wet crankcase with the very small clearances between the flywheels and crankpin with the cases, especially the lower cases.  I would think the ineritial losses that would result would pretty much cancel out any power gains you've made in the upper end. 
And this is without considering the oil that is going to be slinging around, especially up into the lower jug, where the best control ring and drains just aren't gonna get it all.

As far as running the gears in the same oil as the engine, (i think thats what was implied), the viscosity of engine L.O. will change substantially from start-up to tie-up, and that doesn't sound like a very desirable characteristic with which to operate a drivetrain.  Not to mention that some of the worst aspects of the combustion process end up in the L.O., : i.e. carbon, sulphur, water, sulphuric acid, as well as the facets of engine wear, iron, aluminum, bronze, silica (okay, thats only some of us).
In the photos of the engine I looked at, I would think the bulls-eye (sightglass), is indeed for the sump, hopefully segregated from the crankcase.
There is a vent (or something similar) far back on the right side case, and outboard the countershaft sprocket.  (Crankcase/sump vent?)  There appears to be a "thread-in type filler cap forward of that, just inboard of the kicker.  The nest of gears, which Kevin M. has said is pretty much the same as the current 5-speed package, appears to be in a segregated, although contiguous case (Unit construction) with the main package, and that having the traditional vertical split.  (Yeah!).

That primary drive is indeed chain, and that with its proprietary case also, but that clutch pack looks to be a whole lot fatter. 

I think overall, the entire lower case package looks to be a little fatter.

If they did what I think they did with the oils, I'll buy one. 

Sorry to ramble here people, it's my marine surveying background. 

Here's one for the suggestion box.  Why don't  they offer, in the forum, an "Ask Kevin" segment?  Or whoever.  A rumour mill alleviator? 

Just a thought anyway. 

SteveJay

t120rbullet

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Re: New Bullet Engine
« Reply #18 on: December 02, 2007, 04:25:08 PM »
You can have a unit motor without sharing the oils.
My 68 Triumph is a unit motor, the motor itself is a dry sump with a external oil tank. The gear box runs 75w90 gear dope and I run Type F ATF in the primary.
I think somewhere around 71/72 they started sharing the primary oil and the motor oil but I never had one of them "newer ones".
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stipa

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Re: New Bullet Engine
« Reply #19 on: December 03, 2007, 04:21:53 AM »
Absolutely T120.  I had an old bonne myself.  I can't imagine the ironheads, or even the evo sportsters for that matter, with a common oil for the engine and the gear train. 
I think this (Unit construction motor), looks like a prety well thought out machine.  I'm sure it'll have a few teething pains, but overall it works for me.
It looks like chain access will be  a bit more convenient;  like that right side drive system.
One thing that does appear a little funky though, is the position of the kickstarter;  just looks too far forward.  Hmmm.

Steve

hutch

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Re: New Bullet Engine
« Reply #20 on: December 03, 2007, 02:43:14 PM »
Most all bikes that have a primary chain have separate oils like the Triumphs . No one has said about the new Bullet motor yet. Most Japaneese bikes don't have the primary chain and share the oil for the trans and motor.   Hutch
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Foggy_Auggie

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Re: New Bullet Engine
« Reply #21 on: December 03, 2007, 06:16:33 PM »
Most Japaneese bikes don't have the primary chain and share the oil for the trans and motor.   Hutch

They will still have an internal primary chain taken from the center of the crankshaft for multi cylinder engines and from the crankshaft end on single cylinder.  Sometimes the primary chain sprocket is right beside the overhead cam(s) chain sprocket.  And the clutch buildup will include a cush hub.  There is no direct gear on gear mesh absorbing the undampened combustion pulses of the engine.  This would cause fractures of the hardened gear teeth from metal fatigue.

Regards, Foggy
« Last Edit: December 03, 2007, 06:18:41 PM by Foggy_Auggie »
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hutch

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Re: New Bullet Engine
« Reply #22 on: December 03, 2007, 09:41:56 PM »
Foggy, what I meant was the long horizontal chain between the crank and trans like on the Triumph even though it is a "unit" motor, with a separate internal trans case, not like the compact Japaneese setup, that allows for both trans and motor to share oil, examples of which are my Kawasaki w650, most 60's-70's Japaneese bikes, and my 2006 Suzuki Savage 650. Sorry about the confusion.    Hutch
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Foggy_Auggie

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Re: New Bullet Engine
« Reply #23 on: December 04, 2007, 12:41:29 AM »
Sorry about the confusion.    Hutch

No problem Hutch! ;)

They don't call me and my Bullet  "Foggy and Clyde" for nothing!

Regards, Foggy
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cyrusb

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Re: New Bullet Engine
« Reply #24 on: December 06, 2007, 01:51:54 AM »
A pretty good reason for dry sump is if you eliminate the the "oil pan" under the engine you can now locate its mass lower in the frame, a huge plus for bikes and even cars.

hutch

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Re: New Bullet Engine
« Reply #25 on: December 23, 2007, 12:17:39 AM »
Most all bikes that have a primary chain have separate oils like the Triumphs . No one has said about the new Bullet motor yet. Most Japaneese bikes don't have the primary chain and share the oil for the trans and motor.   Hutch
Kevin has answered the question about "shared" oil between the motor and trans, in the Enfield news section. The thread is "when do the new engine and designs come out " thread. They DO run in the same oil. As long as the trans is designed for it, no problem. As mentioned more "gunk" will be running in your crank bearings and trans, but the Japaneese have been doing it for years. As I stated in the other post, that is just a good reason for a magnetic drain plug.     Hutch
« Last Edit: December 23, 2007, 12:25:43 AM by hutch »
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