Posts
155
Joined
10/24/2008
Location
Summerdale, AL
US
Edited Date/Time
4/9/2020 5:44pm
Year/Make/Model: 1980 HONDA 125 ELSINORE
MOTOR SPECS – 2 STROKE (MOD)
CYL: OEM / TEFLON COATED / BORE:56.50mm
HEAD: OEM / TEFLON COATED
PISTON: WESICO. BOOST PORT HOLE MOD / DOME CERAMIC COATED / SKIRT COATED .000.5
SQUISH: .031.5 (.8MM)
PISTON CLEARENCE:.002.5
RING GAP: .009
BASE GASKET: OEM
HEAD GASKET:COPPER
PLUG: NGK BR9EIX GAP ( .022). ADDITIONAL 1MM SPARK PLUG SPACER
CRANKSHAFT: OEM. BALANCED / REM PROCESS / ROD SHOT PINNED AND REM PROCESS /
PEN WELDED. ROD SIDE CLEARENCE .021 / JOURNAL SPREAD 2.167.5 AT PEN AND 180
OPPOSITE OF PEN.
REED BLOCK: V-FORCE / OEM REED BOOT
MOTOR BEARINGS:CERAMIC
CLUTCH: OEM CLUTCH BASKET. PRESSURE PLATE / HUB COATED
CASES: OEM. TEFLON COATED
PIPE: PFR
SILENCER: PFR
IGNITION: PENTON ANALOG
STATER PICKUP CLEARENCE: .010
IGNITION TIMING: .051 (1.3MM) BTDC
CARB: MIKUNI 38 MM...
MOTOR SPECS – 2 STROKE (MOD)
CYL: OEM / TEFLON COATED / BORE:56.50mm
HEAD: OEM / TEFLON COATED
PISTON: WESICO. BOOST PORT HOLE MOD / DOME CERAMIC COATED / SKIRT COATED .000.5
SQUISH: .031.5 (.8MM)
PISTON CLEARENCE:.002.5
RING GAP: .009
BASE GASKET: OEM
HEAD GASKET:COPPER
PLUG: NGK BR9EIX GAP ( .022). ADDITIONAL 1MM SPARK PLUG SPACER
CRANKSHAFT: OEM. BALANCED / REM PROCESS / ROD SHOT PINNED AND REM PROCESS /
PEN WELDED. ROD SIDE CLEARENCE .021 / JOURNAL SPREAD 2.167.5 AT PEN AND 180
OPPOSITE OF PEN.
REED BLOCK: V-FORCE / OEM REED BOOT
MOTOR BEARINGS:CERAMIC
CLUTCH: OEM CLUTCH BASKET. PRESSURE PLATE / HUB COATED
CASES: OEM. TEFLON COATED
PIPE: PFR
SILENCER: PFR
IGNITION: PENTON ANALOG
STATER PICKUP CLEARENCE: .010
IGNITION TIMING: .051 (1.3MM) BTDC
CARB: MIKUNI 38 MM...
hi this patrick,
i have a 1980 cr125 in the shop and it has the original kehin carburetor. i remember that people were putting mikunis on back then,but i cant remember what the jetting was way too long ago. ii i were to put one on the bike which is stock is a 34mm mikuni ok, i would need slide cutaway,needle ,main and pilot recomemdations, i would rather not start from scratch.anyone out there put one on and i does have a pfr pipe,also it touches the frame downtube,
any one got starting specs for the carb and did your pfr hit the frame
thanks in advance
patrick
Sorry I do not have the bike that I posted in the original post anymore. But here are some info that might help.
Mikuni VM34 on a 1980 CR125 — Starting Specs (sea level, stock engine with PFR pipe)
A VM34 sold specifically for the Honda Elsinore 125/250 comes set up with a 270 main, 40 pilot, 159 P-6 needle jet, 6F5 needle, and 2.5 slide — that's as close to a factory-spec starting point as you'll find for this application. Re-MX Inc
For your bike with the PFR pipe (which adds top end over stock), lean the main ever so slightly — a 260 may actually be closer. A 79 CR125 with a VM34 swap was found with a 260 main and 52 pilot already installed, suggesting that range is in the neighborhood, though the 52 pilot is on the rich side for most conditions. The consensus from old-school guys doing this swap is start with a 300 main and a 35 pilot with a 2.5 slide as a safe rich-side baseline, then lean down from there. Vital MXvitalmx
On the PFR pipe hitting the frame downtube — that's actually a known issue with that pipe on the 1980 CR125. The PFR (and similar expansion chambers of that era) were designed with a fairly aggressive tuck but the header routing often puts the mid-section right against the downtube. Most guys either used a small rubber isolator/cushion wrap to prevent wear-through, or slightly massaged the pipe with heat to get a bit more clearance. It shouldn't be structural contact under load, but you don't want it vibrating against bare steel either — it'll eventually rub through both. Worth wrapping that contact point with header tape or a split rubber hose section at minimum.
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