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  #1  
Old 16-07-2017
Stark Stark is offline
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Question Splitting engine without Removing ?

I'm in the process of fitting a big-bore kit to my 15' 500 exc which requires sending the cylinder and center case to the workshop.

I've never disassembled an engine before, so I would like to know if it's possible to remove these parts without removing the engine from the bike ?

I had the engine out not long ago to frame the bike and it was a major pain! Hoping to avoid doing it again.
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Old 16-07-2017
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Originally Posted by Stark View Post
I would like to know if it's possible to remove these parts without removing the engine from the bike?
If you're only going to 570cc the bottom end can stay in the chassis. The bigger capacities require the cases to be fly-cut with the crank out of the cases.
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Old 16-07-2017
Stark Stark is offline
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Nutty- This will be for the 610 kit. All that I know is, the center cases need to be bored out 2mm.

Does that necessitate removing the whole engine though ? Is there any conceivable way to remove these parts but leave the remains inside the frame as to avoid detaching it's many tentacles ?
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Old 16-07-2017
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Quote:
Originally Posted by Stark View Post
Nutty- This will be for the 610 kit. All that I know is, the center cases need to be bored out 2mm.

Does that necessitate removing the whole engine though ? Is there any conceivable way to remove these parts but leave the remains inside the frame as to avoid detaching it's many tentacles ?
This is a split the main cases drop the whole gearbox contents on the bench, pulling the engine in and out is the easy part.

Do you really need to do this, you'll end up with similar horsepower just lower in the rev range. That's the upside, it'll also be more oversquare and want to stall more often if doing tight low speed riding.
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Old 16-07-2017
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Quote:
Originally Posted by Stark View Post
Nutty- This will be for the 610 kit. All that I know is, the centre cases need to be bored out 2mm.

Does that necessitate removing the whole engine though?
Yep. The motor needs to come out.

As Tom said, the crank has to be removed, the cases reconnected and the barrel spigot land re-machined 2mm greater diameter.

I'd go a 570, it's all any sane person ever needs. The stock module won't allow enough initial spark advance to get the best out of a 610cc capacity down low in the revs anyway.

The 570 kit can be fitted in chassis. They go like stink, use all OEM parts and use SFA fuel.

If the 610 is an Athena kit, you'll need to be good on the tools anyway...
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Old 16-07-2017
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Tell me more about the 570. Is that just dropping the berg jug and piston in? Do you need to remap? Head is the same I think from memory?
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Old 16-07-2017
Stark Stark is offline
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Crud! Thanks for pointing that out.

Since this is mostly for SM usage, I'll gladly take any and all power that's on offer. Was originally eyeing-up the 660 kit, but was told it can be a little jerky.

The 590 kit has a claimed 62hp with stock setup. 610 kit = 66hp and 660 kit +ECU = 86hp!

I'm not sure the 590 kit is even worth the trouble as it's not a dramatic increase in power over what I have now. 70hp was my intended target. ECU alone adds 8hp, but it costs nearly as much as the whole 610 kit!

Well, it's either a big-bore or Alpina Pro Matrix wheels. Very tough decision!
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Old 16-07-2017
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Quote:
Originally Posted by Stark View Post
Crud! Thanks for pointing that out.

Since this is mostly for SM usage, I'll gladly take any and all power that's on offer. Was originally eyeing-up the 660 kit, but was told it can be a little jerky.

The 590 kit has a claimed 62hp with stock setup. 610 kit = 66hp and 660 kit +ECU = 86hp!

I'm not sure the 590 kit is even worth the trouble as it's not a dramatic increase in power over what I have now. 70hp was my intended target. ECU alone adds 8hp, but it costs nearly as much as the whole 610 kit!

Well, it's either a big-bore or Alpina Pro Matrix wheels. Very tough decision!
Big bore will only give more power if the top end can feed enough air, otherwise it simply delivers the power at lower revs. That would make Motard riding/sliding more controllable though.

P.S..People will gob off about more torque, that's another of saying higher horsepower at lower revs in this instance.




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Last edited by Tom68; 16-07-2017 at 10:06 PM.
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Old 16-07-2017
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I don't know nuthin about nuthin.. engines or motard..

But like most things, more speed can usually be found in better technique and carrying through the corners vs trying to chase more peak HP... unless of course you already have great technique and your particular scenario is genuinely being held back by a lack of power.

On the other hand, I know a few blokes who are pretty handy on theirs, and through first hand experience they've both said it's rather costly throwing dollars trying to change a dirt scoot into a motard, and you are much better off buying the right tool for the job from the get go.
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