RDLC crank needed.

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L.B
Posts: 2008
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Location: Hunter Valley,Australia
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RDLC crank needed.

#1 Post by L.B » Mon Mar 05, 2018 6:55 am

Need a complete,intact but worn out,flogged out LC crank sent to someone in US. Be even better if for free....happy to pay postage.
Tia.
Last edited by L.B on Tue Mar 06, 2018 3:37 am, edited 1 time in total.

Bare
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Joined: Sun Jan 29, 2006 2:18 am
Location: vancouver

Re: RDLC crank needed.

#2 Post by Bare » Sat Mar 31, 2018 11:16 pm

Fit a Valvie crank.
It's a superior / stronger crankshaft design and it can be retrofitted to an LC...
easily.

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Ardee
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Location: Central Ontario Canada

Re: RDLC crank needed.

#3 Post by Ardee » Mon Apr 02, 2018 7:45 am

Bare wrote:Fit a Valvie crank.
It's a superior / stronger crankshaft design and it can be retrofitted to an LC...
easily.
What is the difference between the YPVS crank and the LC ?
What needs to be done to fit the YPVS crank into the LC engine ?

Bare
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Re: RDLC crank needed.

#4 Post by Bare » Wed Apr 11, 2018 7:15 pm

1mm wider big end bearings basically .
Doesn't read as much... but it's definitely significant
RZ cranks are a few (2?) mm wider accross the webs as result.
These are direct drop in fits into 'some' LC cases..dependant of what cycle of the production run they were in.
Regardless LC cases can easily/cheaply be flycut to allow for the wider crank .

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Ardee
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Re: RDLC crank needed.

#5 Post by Ardee » Wed Apr 11, 2018 8:41 pm

Bare wrote:1mm wider big end bearings basically .
Doesn't read as much... but it's definitely significant
RZ cranks are a few (2?) mm wider accross the webs as result.
These are direct drop in fits into 'some' LC cases..dependant of what cycle of the production run they were in.
Regardless LC cases can easily/cheaply be flycut to allow for the wider crank .
Thanks for that information, I will keep that in mind. :smt023

kaptiankent
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Location: Newmarket, Ontario

Re: RDLC crank needed.

#6 Post by kaptiankent » Sat May 12, 2018 9:01 pm

I am in the process of rebuilding my LC engine and I think the previous owner installed a Hot rods Banshee crank without machining the cases for clearance. There are scrape marks on the sides of the crank webs and inside of the case sides. I took apart a spare LC engine and measured the Hot rods crank compared to the LC crank and both sides are 2mm wider on the Hot rods one. Other than that all the bearings line up. I am going to have the cases machined 1mm on both sides to allow enough clearance for the Hot rods crank.

Image

Image

350LC crank
Image

Hot rods crank
Image
1978 XT500
1981 RD350LC
1989 RZ350

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2smoke
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Re: RDLC crank needed.

#7 Post by 2smoke » Sun May 13, 2018 12:39 pm

Was this engine running? :smt103 I assume something was wrong with it since you tore it down.
Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

kaptiankent
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Location: Newmarket, Ontario

Re: RDLC crank needed.

#8 Post by kaptiankent » Mon May 14, 2018 8:13 pm

yes, surprisingly the engine was running pretty well before I tore it down. I have owned the bike since 2015 and have put on about 3000k since then. Main reason for the teardown was when installing new TDR reeds I noticed the piston skirts were not modified on the intake side. I was planning on taking the top end apart and cutting the skirts on the pistons and re-assemble the top end.
However, when I removed the top end i noticed the cylinder walls were pretty scraped up. The pistons I removed showed no signs of rubbing so I assume there was a failure in the past and new pistons were fitted without a re-bore. I think the waterpump gear must have broke or something as there was a brand new white plastic gear on there.

I decided to fix the top end properly and have the cylinders bored out. They were at 66.25mm and now are at 66.5mm. As far as I know that is the largest pistons they make for this bike. ended up going with ProX. The ones that I removed were Wiseco (66.25mm)

While the cylinders were at the shop I decided to remove the rest of the engine from the bike and do a quick inspection of the crank since it was halfway torn apart already. Then I got the surprise as seen in the pictures above..........

It must have been a tight fit when they put that crank in there.
1978 XT500
1981 RD350LC
1989 RZ350

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2smoke
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Re: RDLC crank needed.

#9 Post by 2smoke » Mon May 14, 2018 11:54 pm

These old bikes are full of surprises. Sounds like you have it all under control now though.
The water pump gear often breaks when the sidecover is pulled off on all the Yamaha twins.
Colin
79 RD400F Daytona Special
81 RD350LC
89 TDR250
75 Kawasaki H1 500
77 Can-am Tnt250

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JonW
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Re: RDLC crank needed.

#10 Post by JonW » Tue May 15, 2018 12:38 am

Ive heard this on the forums, but Ive never seen one break...
80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD350LC decapitation project
82 RD250LC JDM '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

kaptiankent
Posts: 8
Joined: Mon Jul 17, 2017 10:20 pm
Location: Newmarket, Ontario

Re: RDLC crank needed.

#11 Post by kaptiankent » Tue May 15, 2018 10:52 pm

The spare engine that I took the other crank out of had a trashed top end. upon removing the side cover I found the waterpump gear in pieces. I think the issue is when installing the side cover if the gear is not lined up it has the potential to break if forced on. I usually pull the oil pump and water pump cover before putting the side cover on so that I can make sure the two plastic gears are meshed with the one on the crank.

I will let you know how it goes. Hoping to get her running before summer is over. lol
1978 XT500
1981 RD350LC
1989 RZ350

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JonW
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Re: RDLC crank needed.

#12 Post by JonW » Thu Jul 19, 2018 4:44 am

Any news?
80 XT500 Supermoto!
81 RD350LC Resto
82 RD421LC Hybrid
82 RD350LC decapitation project
82 RD250LC JDM '251LC' YPVS
83 RZ350 Resto
84 RZ500 Resto
85 RZ350 F1 Resto
86 RZ350 F2 Resto
86 RZ350 F2 Hybrid

Like Watches? www.PloProf.com & www.DeskDivers.com

evan_calgary
Posts: 1368
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Re: RDLC crank needed.

#13 Post by evan_calgary » Thu Jul 19, 2018 12:46 pm

kaptiankent wrote:The spare engine that I took the other crank out of had a trashed top end. upon removing the side cover I found the waterpump gear in pieces. I think the issue is when installing the side cover if the gear is not lined up it has the potential to break if forced on. I usually pull the oil pump and water pump cover before putting the side cover on so that I can make sure the two plastic gears are meshed with the one on the crank.

I will let you know how it goes. Hoping to get her running before summer is over. lol
I think you are right. I have taken apart a couple seemingly low mile since rebuild bikes that have broken water pumps. I have also seen the gears jamming and try to leave off the stator side where possible to turn when reinstalling.

Wish I could help with a crank LB! I have a couple leads but nothing firm right now. I think you should convince Rory to sell one of his...

Bare
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Location: vancouver

Re: RDLC crank needed.

#14 Post by Bare » Thu Jul 19, 2018 11:50 pm

Sadly just like Houses... Everybody and their Dog thinks they can DIY anything. Clearly not :-)
Nothing wrong with fitting a Valvie /Banshee crank inna LC case.. It's a Far better crank TBH.
Some LC cases accept the things nicely .. some don't... dependant of their position/time on the Yama assembly line.
IF the thing was running decently ?
Doesn't seem much point in adding/machining additional clearances.. does it?
Breaking the Plastic gears on assembly is the signature of a Moron at work.

tacky1
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Joined: Wed May 13, 2015 1:11 am
Location: Pacifica,,

Re: RDLC crank needed.

#15 Post by tacky1 » Wed Jul 25, 2018 3:57 pm

Is there any difference in width or size in an OEM crank and a hotrods crank, plus which one is better. I might just buy a new crank. I can buy either an OEM or HR crank.
1985 RZv500
1984 RZ500 Hybrid
1986 RG500 Walter Wolf
1986 RG500 Skoal Bandit
1984 RZ350
1984 RZ350 Hybrid
1981 RD350LC
1981 RD350LC Hybrid
2009 CR500AF Supermoto 250X
2007 CR500AF 250X
1988 YSR50 (2)
1984 GPZ750 Turbo
1989 VFR750R RC30

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