Brought it home, guy I bought it from had no history, noticed this. Long rod?
Brought it home, guy I bought it from had no history, noticed this. Long rod?
Yep, looks to be a long rod lower end from a TRX with a ATC top end.
YAMAHA 450 HYBRID
85 350X- RED
85 350x -BLACK
86 350x-WHITE (with Goki)
85 250r
83 atc 70
84 atc 70
84 atc 110
09 yfz 450
2006 Arctic Cat Prowler
RZR XP 900
Or a stroker crank
78 atc 90/180cc Dickson Full Suspension
76 ATC90/180cc Nicholson
77 atc 90 Dickson Full Suspension
84 KLT 110/123cc Powroll Racer from 80s
87 atc 125m stock
84 atc 200x Curtis Sparks
84 atc 200x Powroll My race bike from 80's
83 atc70/108cc Powroll blue Xmas Special
81 atc185s HP-ATC full suspension
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Hi Guys,
Seems like this might be a beginner question, but can someone explain to me why it is called a "long rod", and what externally demonst? It looks like the Bore and stroke for the 85 and 86 ATC 250R's is 66 X 72 mm, and the 86 and 87 - 89 TRX 250R's are also 66 X 72 mm...
What gives it the designation "long rod"
I did a search of the site and came up with nothing which actually explained this.
Thanks,
Sorry, above should say "and what externally demonstrates this?"...
The 85-86 250r engine cases have a different cut out at the front mount than the 88-89.First pic 85-86 250r .Second pic 88-89 250r . The early 250r 85-86 has a short rod the piston wrist pin hole is lower than the 87-89. the bore and stroke are the same . If you run the 85-86 piston in the 87-89 motor the piston will come out of the top of the bore by about 5 mill thats why you need the spacer plate. 87-89 250r over bores only go up to about 68-69 mill the big bore 250r kits are kinda based off the short rod motor.
Last edited by atc300r; 10-13-2017 at 10:08 AM.
250r rules
Makes sense now. Thanks for the clarification.
I was told at one time that Honda went to a longer rod to lessen the angle of the rod for dependability. It doesn't seem like that small amount of change would do much though.
YAMAHA 450 HYBRID
85 350X- RED
85 350x -BLACK
86 350x-WHITE (with Goki)
85 250r
83 atc 70
84 atc 70
84 atc 110
09 yfz 450
2006 Arctic Cat Prowler
RZR XP 900