Cam differences '83 VF750F vs '85 VF700F?

Hello, I'm having the pitted/scored cam shafts and rockers from my '83 VF750F repaired but am wondering if I can use the cams and rockers from a '85 VF700F parts bike I have. The rockers seem the same but are the cams different between the two bikes? Here's the manual page showing cam specs for the 750. If anyone has the same page from the 700 manual, could you post it? Also, is there any difference between the bikes' oil supply lines? Thank you!

 

Oil pipe is the same all years / engine sizes.

The cams are different part numbers so there is something changed. If you use all 4 cams, I don't think there will be any issues. The 700 cams might actually be "hotter".

I will check my library for a 85 VF700F Honda SM, but I don't think I have one.

 

I found a Factory Service Manual for the 85 700F. That page (actually the whole section) is identical, with no differentiation regarding 700 vs 750, or years. Cam installation and timing is unchanged.

 

Thank you for the quick reply and helpful information. Yes, I will use all four cams, and also the rockers.
The only difference I notice is the rocker adjusting screws. Those on the 750 have a non-threaded extension for the screwdriver notch, while the 700 screws do not have this extension. This doesn't matter since the thread pitch is the same on both.
Cheers,
Bill

 

Is there a California difference in this case? A lot of Honda and Suzuki motorcycles I've worked on over the years had California model differences in the camshaft (as in, a definitely less-hot camshaft due to California emissions)

 

I don't know if there's a CA difference. I have the cams removed from both bikes and will compare them and post photos tomorrow. A quick comparison indicates they're basically the same but oil delivery holes are in different locations.

 

The VF700/750F did not have different cams for CA. Just different from each other. As long as the lift on the 700 cams isn't ridiculously high, there should be no issues.

 

OK, thanks for checking.
Here are photos and a drawing comparing cams from a '85 VF700F and '83 VF750F. They appear the same with the following differences (which I assume, are improvements):
700 has an oil groove on one more journal than the 750;
700 has 3 oil holes on each side of the drive sprocket (each set positioned 180-degrees from the other);
700 has oil holes on the outer journals located closer to the journal's center (except on EXRR2 and INRR2 where one hole is closer to the journal's inner edge like all of those holes in the outer journals of the 750);
750 has one oil hole that passes through the shaft and is open on both sides (oil holes only pass through one side of the 700 shaft)

If shop manual specs for both bikes are the same I would not think the 700 cams would have a greater lift or be hotter than those on the 750...but let me know if I'm missing something.

I will use all four cams and the rockers from the 700. I'll let you all know how it goes.

Thanks!

 

I am a little skeptical of those SM pages. The date is 1983 with no addendum for 85. And if the 85 was a better cam with the same dimensions, they didn't supercede the 83 to the 85 part number. They each superceded to a different part # when they were still available.

I still think you'll be just fine, but it would be nice to find the actual lift / duration numbers for the cams. Some Honda Service Manuals list that info.

 

Hmm...I'm not sure how I'll determine lift/duration numbers other than referring to the SMs. Distance from the tip to the "heel" of the lobes is the same but I haven't measured the angles of the lobes. So many questions...

 

You've verified no crazy lift. Install them and be done. Probably the best cams you could put in a VF750F.

 

Thanks for all your help, Captain. I need to order a few rockers and will then install the cams. I'll let you know how it goes.
Cheers!

 

Here's the epilogue to my posts about using '85 VF700F cams and rockers in my '83 VF750
F: They work great! I installed and indexed the cams per the instructions in the VF700F/VF750F shop manual, rotated the crankshaft several times to be sure valves and pistons didn't hit, and the engine fired up immediately and smoothly. Whew! I can't say if there's a performance increase since I've not ridden the bike much with the stock cams but it feels strong and runs smoothly.

 

Nice!!!!!! Man, that's good news.

 

And you know what? There will be a performance increase. The same one where your car is faster after washing it on a sunny day. Just going thru this, it will feel better. Here's to a great test ride.

Cheers.

 

Ha, ha...you're so right. The test ride was great. Now I can't wait for decent weather to take it on a long trip. Cheers!