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xr600 - separate crank area from transmission

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hi

i just wonder to ask you guys what you think about separate crank area from transmission and clutch. exactly like 2stroke engines.

im in progress to build my xr600 for motocross and how you good know clutch is used much more in motocross

than on the road and transmission as well... and oil is getting more dirt and higher temp on the motocross track...

so, my idea is to put bearings with seals on the right side (clutch side) and weld new aluminium wall for separate crank and 

gears... to make almost same cases like xr650

down here are some pct off my idea

hope guys you understand me :D

and i wait for ur comments

 

(FIRS PCT IS XR600 CASE WITH MY IDEA)

(SECOND PCT IS XR650)

 

case w paincie.jpg

IMG_20151107_210848.jpg

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Seems like far too much trouble for little gain. I think there is a clearance issue between the crank and mainshaft gears. Not really any room for a wall in there. How would you oil and separate oil from the top end? Drainback down the camchain tunnel would have to be isolated as much as crank oil.  Then what would you do about the flywheel and ignition coils which are cooled by engine oil. You would need to have a multiple oil pump and tank system which would add weight and complexity. This is an engineering exercise that really can't be addressed by a retrofit in these engines. I think you'd be better off forgetting about this and adding an oil cooler instead.

Edited by valvesrule

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I'd try it...on someone else's bike...if they paid me a bunch, a whole bunch, to do it.  

 

I see many hurdles, most of which valvesrule mentioned above.  The picture below shows how tight it gets when everything goes back in the case.  

 

You'd have to do some re-routing of internal, cast in, oil passages to isolate the oil heading into the transmission shafts and kickstarter gear (outside the chamber you are isolating with your bulkhead), as well as plug weld all the multiple cast in holes between in the inside and outside of the cases.  

 

Lots to consider.  I don't think that this plan is the answer you're looking for.  

 

I'd search for better oil, better clutch, additional cooling (oil capacity, big fins, etc,)...or a motocross bike.  There is a reason they are built the way they are built.  Don't get me wrong, I love a good project, but I don't see this one turning out like you are hoping.

 

 

20150525_122919.jpg

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thanks guys for answers! now i know its wrong idea :)

do you think that oil cooler will enought ?

what oil you recomendet for this xr600 1984 engine? (on motocross track)

there is any good clutch to buy??? (HINSON) or good plates for this engine???

ONCE AGAIN, THX!!!

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i dont think there are some dumb ideas out there, just some ideas that are better left at that stage. how about adding 2 extra cam lobes or a custom cam sprocket making the ratio 1:1 so it runs 2 stroke? durability of valve train might be a limiting factor. another of those ideas. 

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Hello, its all about lubrication. Two strokes mix oil with gas to lube the piston and crank. They need a separate transmission with lube oil. My XR650L uses oil under pressure to lube the top end and transmission. This pressurized oil flows through gallies to journal bearings located on all moving parts. The type transmission lube on two strike transmissions is refereed to as a slinger lube system because it uses the spinning mechanical systems to through oil to wear surfaces. Dry sump XRs need the oil pressure by design which eliminated the windage loss in slinger engines.

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I'd try it...on someone else's bike...if they paid me a bunch, a whole bunch, to do it.  

 

I see many hurdles, most of which valvesrule mentioned above.  The picture below shows how tight it gets when everything goes back in the case.  

 

You'd have to do some re-routing of internal, cast in, oil passages to isolate the oil heading into the transmission shafts and kickstarter gear (outside the chamber you are isolating with your bulkhead), as well as plug weld all the multiple cast in holes between in the inside and outside of the cases.  

 

Lots to consider.  I don't think that this plan is the answer you're looking for.  

 

I'd search for better oil, better clutch, additional cooling (oil capacity, big fins, etc,)...or a motocross bike.  There is a reason they are built the way they are built.  Don't get me wrong, I love a good project, but I don't see this one turning out like you are hoping.

Thanx for the visual assistance. Getting a picture up was a bridge too far considering the viability of such a project. Nice mental engineering exercise, practicality wise not so much.

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