Vintage Dirt Bike Q & A

Can someone give me thier thoughts on which one of the Red Rockets (1978,1979 or 1980 Honda cr250's) had a better motor or any other significant differences?
Thanks,
Layne

The motors for all three years are very similar with a few exceptions. The biggest
changes ocuured in 1980 when Honda went with a double downtube, cradle like
frame and moved the exhaust port to the center of the cylinder. Honda changed
the side panels to the FIM standard and equipped the bikes with reservoir shocks
and air capped forks. 1980 also was the first year for plastic fuel tanks and no
kickstands on CRs.

If you want to race vintage, all three years make great foundations for building
a stout racer with the 1980 model providing the most rigid frame. Just get yourself
a rulebook and a bag of money.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

All three years make great historic racers. The bikes are fast (enough) and reliable with good parts availability. For all years I would plan on upgrading the suspension; 43mm Honda forks on the front-end and after-market shocks. All the other stuff I would put in the nice to have category even though I've dropped a bunch of coin on my bike (hey...I'm weak and admit it.) The 78/79 engines are considered "top-end" while the 80 is more torquey and mid-range. You can get after-market pipes to adjust if you want. The frame is more rigid on the 80 because of the double downtube design. Even though I have a 78/79 hybrid I would go for a 80 model and look for an aluminum works-style tank from Dogger's Japanese connection.

_________________
Michael Stiles
1979 Honda CR250R Elsinore | 2006 Husqvarna SM510R | 2007 Service Honda CR500R-AF

The 78 cylinder had a large unbridged intake port and was reported to rev higher than the 79, which had an intake port bridge added to the cylinder. As notede, the 80 was a center port barrel, but I don’t know if the port timing as changed. The 80 engine lost a lot of the rev that people liked in the 78-79.

One of the differences between these engines is the ignitions. The 78 and early 79’s had different ignitions available, presumably mapped differently for different performance features. These were denoted A, B or C, marked on each of the CDI unit, flywheel and stator cover. Mid 79 they came as D, E or F, with the same component set. According to the Fox CR guide from back in the day, one set or the other included a rev limiter (I believe the D-F set). The 80 had an entirely different ignition; the CDI is different and the stator plate and flywheel are not marked with any letter designation. This different ignition may produce the torquey character of the 80’s, as I recall articles about swapping out the 80 ignition for one of the earlier ones to restore the rev. You can come across basically unused 80 ignition sets from time to time that look like new take offs.

People seem to want the E ignition set these days above the others, primarily based on the legend that the factory team riders preferred it. I think this is referenced in the Fox guide, but you can see in Terry Good’s photos of his Tripes 79 RC250 center port bike that an E ignition is on that engine.

Basically, you can do a lot of mixing and matching among the 78-80 bikes to the extent not limited by the single-double downtube difference between the 78-79 and 80 models.

A works style tank for the 80 frame . . . I'm licking my lips.