Spliting the lower half engine - Possible?

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
Post Reply
brogger
Settled in member
Posts: 2
Joined: Fri Oct 10, 2008 4:01 am

Spliting the lower half engine - Possible?

Post by brogger » Fri Feb 20, 2009 3:21 am

Hello to everyone,

Just would like to know if its possible to remove the piston so I can get to the rings,
without having to tear down the whole engine.

Thinking out loud, if I remove the side engine covers (clutch and generator covers) and then the oil pan. Would it enought for me to be able to split the lower half???

I was barely finishing the engine after skimming the heads, shimming the towers, checking valve clearances and other adjustment, then after a compression test one of the cylinder still has low pressure which leaves me to suspect that the problem is the piston rings. Now I hate to go back and redo everything again when I replace the piston rings. So is there a way around this?

TIA

User avatar
Jon
Site Supporter
Site Supporter
Posts: 165
Joined: Tue May 20, 2008 2:00 am
Location: Brisbane

Re: Spliting the lower half engine - Possible?

Post by Jon » Fri Feb 20, 2009 8:13 am

Just had a quick look at a spare block I have here, the web for the crankshaft main bearings goes past the edge of the cylinder on at least the front right cylinder (didn't look beyond that).

So answer is no for pulling pistions via the bottom of the crankcase sorry.

If you kee ptrack of where you take all shims ect from should be able to disasemble and reassemble fairly easily.

Squirt a bit of oil down the offending cylinder, if it is rings the compression will come straight up on that one.

What did the bore look like whil eyou had the heads off?

regards
jon
Honda NC30
Ducati 900 S2 (under constrcution)
Moto Guzzi Le Mans III
Honda CB550F2
BMW R90S

User avatar
CMSMJ1
Moderators
Moderators
Posts: 7152
Joined: Thu May 01, 2008 9:42 am
Bike owned: NC30-No9
Location: Chesterfield, United Kingdom

Re: Spliting the lower half engine - Possible?

Post by CMSMJ1 » Fri Feb 20, 2009 8:27 am

I kind of recall that the G force guys posted something like this a while back. As they werre stripping motors a lot adn swapping pistons etc..

I will try a search -

You want posts by G force performance, mike lohemeyer et al.

If I am making it up then apologies in advance..but I have a decent memory for stuff..lol
IMPERATOR REX ANGLORUM

The V4 is the law..

NC30 - No9 - my old mate

User avatar
Jon
Site Supporter
Site Supporter
Posts: 165
Joined: Tue May 20, 2008 2:00 am
Location: Brisbane

Re: Spliting the lower half engine - Possible?

Post by Jon » Fri Feb 20, 2009 8:36 am

I think i remember the thread you were talking about Mark.

If i remeber correctly it was about splitting the crankcase without removing the head to replace gearbox components.

regards
jon
Honda NC30
Ducati 900 S2 (under constrcution)
Moto Guzzi Le Mans III
Honda CB550F2
BMW R90S

brogger
Settled in member
Posts: 2
Joined: Fri Oct 10, 2008 4:01 am

Re: Spliting the lower half engine - Possible?

Post by brogger » Fri Feb 20, 2009 2:47 pm

Jon, thanks for taking time to check your spare.

I found this site with photo of the motor split in half, I think his a member of this forum and hope he doesn't mind me posting it for reference.

http://www.rvf.dk/My-RVF-Trackbike/slid ... Ratio.html" onclick="window.open(this.href);return false;

With the gear assembly in place, do you think the crank shaft will come off?
I don't see a way to remove the piston with the crank shaft in place as the counter weights gets in the way.

Obviously I have never done this before and in denial, still think its plausible. otherwise somebody here could shed the truth.

Post Reply