i just traded a 1969 vw bug for a 1986 honda vfr 700, i think i was a good trade but that is not my question... it is (as stated) a 1986 but has a 1987 engine in it. and as far as i can find the only difference in the engines is the CMP (camshaft position sensor) and from any one i have asked so far has said that the 86 CMP is 360 degree sensor and the 87 is a 180 degree sensor, now my question is what do i have to do to make the 87 sensor work with the 86 bike... i have called the honda dealer and found that the 86 and 87 CDI box is the same, but the connector on the CMP is different. so i have been told that i need a 87 wiring harness, is that true? or would i be able to just wire it in directly? and is there any other problems i should expect with this swap? anything you guys know would be great... and just a side note i am an automotive mechanic and there is not much i can't do mechanically... i just dont know wat to expect, so any tips tricks or knowledge you have to share or if you know if a place i can find some good info
thanks alot
dom
im surprised somebody even got an 87 motor to run on an 86 bike with the 86 wiring harness and CDI box....ive had both an 86 and an 87, and the CDI boxes were different. as for the camshaft position sensor, this part actually bolts into a hole that is in one of the cylinder heads (i believe the front).
the way i see it, ya have 2 choices. (a) stay the course and just ride the bike as it is. be happy that somebody seems to have managed the impossible. (b) go out and find a front head for an 86 model 700 or 750 (same head), install it, and youll have a place for a camshaft position sensor. use the CDI box and wiring harness from the 86 and youll be fine with this option.
as far as your analysis of the 86 vs 87 engines, youre actually right on the money. the camshaft position sensor is about the biggest difference between the 2 bikes, and there are some little wiring harness differences in there, too. additionally, the ONLY differences between the 700 and 750 motors are the crankshafts and connecting rods. otherwise, the motors are pretty much the same thing.
some key differences ive found with the 86 vs 87 wiring harnesses are that the combo switches on the handlebars have different connectors between the 2 yrs, and the CDI connectors are different. obviously, the 87 harness wont have the camshaft position sensor connector on it.
now that i think of it....IS your bike even running?! if not, then you may actually have to go through a lot of BS to get it running with that 87 motor in there.
I know this an old post but are you saying that if you swap crank and rods on an 87 700 you could have an 87 750?
[image: View Post]18acres, on 20 December 2010 - 05:08 PM, said:
I know this an old post but are you saying that if you swap crank and rods on an 87 700 you could have an 87 750?
The major difference is the crank with a shorter stroke and rods are longer to compensate.
Knowing Honda the carb jets and the ignition witll be different, I have just been looking at cam part numbers for 86, 87, 88, 89 models from diffenering euro countries and there are loads of differences.
Richard