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Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 4:51 pm
by Supereibar
Hello peeps, I have a friend who has provided an engine, an RB250 kit, a high performance crank, a 6 plate clutch, a 34mm delly, a varitronic elec. ign. kit and is now just waiting to have all the elements that I ask him for to ship the whole thing to me to do the build up.
My question is, I've heard horror stories about the RB kits and really dont know what to tell this guy as far as modifications to make his kit reliable, what would you reccomend as far as the crank goes? Is the high performance crank safe after its trued or does it need to be modified/machined? Would it be a better idea to replace the con rod for an RD400 one? How about the piston? Any suggestions for the whole front end set up?
Many thanks in advance. I need all the help I can get so all comments are welcome!!!
Jaime
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 5:25 pm
by RICSPEED
go to the lam tech page and try a search ...there should be a few threads on this subject jaime

Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 6:58 pm
by Supereibar
Nothing... C'mon!! Where are the tuning boys?????
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 7:28 pm
by camel
well firstly....what crank have you got?
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 8:03 pm
by rocho68
just built one for a mate , what crank you using ? , also be careful as weve had trouble with the af flywheel breaking down at top revs , make sure you replace everything and dont skimp on nothing else it will come apart like a cheap watch ........................
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 10:25 pm
by Supereibar
You guys are totally right and I do have clear that we are starting with a bare casing. From that point on is all welding, then machining and C4 bearings. Vitton seals any good?
My mate hasnt specified on the crank, but aparently is a high performance crank, also produced by AF. Any idea on how these cranks are made?
Many thanks for your comments!
Jaime
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 11:21 pm
by Lamaddict
Lubrication on the big end was a greater requirement for the RB's, so I'd expect to see the conrod big end have big grooves cut in for better lubrication. Personally I like Yam rods on SIL webs but don't know if anyone has tried one on an RB.
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 11:28 pm
by Supereibar
Cutting grooves inside the conrod big end????
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 11:35 pm
by RICSPEED
Supereibar wrote:Cutting grooves inside the conrod big end????
a bigger slot cut in the end

:smug: :bouncing:

:fb:
Re: Help needed. Building an RB250 for a mate
Posted: Sun Nov 21, 2010 11:44 pm
by Supereibar
you reckon?