1984 VF1000R right side coil cuts out after 2,500 RPM? help

Hi, I'm new to the VFR world. I recently purchased a 1984 (Paris) VF1000R with 9.5K miles. It's been wonderful until now. It won't rev high. After A LOT of tinkering I have managed to discover that both ignition leads on the right side coil (two front cylinders) cut out / stop sparking after 2,500 rpm. Both spark continuously on left side coil (rear cylinders) Does anybody have a suggestion? Rev limiter prematurely coming on? CDI? Sparking units? Pulse generators? uhhh, I don't know where to go from here? Thank you for your time.

 

Good to see another Interceptor owner, not many of us around these days, mine is a 65 and I ride it regularly, did 70 miles on it yesterday. Electrical probs like this can do your head chasing them but my first test would be to swap the coils around and see if the problem changes cylinders and then come back here and see if the thought tank can help

 

Ignition box is bad. Swap your ignition boxs and see if problems moves to other (rear) cylinders. The swap is just for trouble shooting. There is a difference between boxes 1/3 has tac, 2/4 fuel pump, but they both will fire the plugs correctly. Then ebay is your friend. I do have a 2/4 box for a VF750F if you need one. I think they are the same.

 

I had a CDI Box with 100% failure,,.. fixed it.
The wires came onto the board on large Pins, soldered to the board.
There were tiny Ring Cracks around the pins where they were soldered on to the copper side of the board.
When they Solder Flow the boards, not enough heat gets into the large metal pins,,.. Cold Solder Joint.
Just resolder with good heat,,.. also resolder the pins on the Power FET, just in case.
My board was glued into the plastic box, but was able to pull with pliers on the Heat Sink while heating the plastic box (hair dryer).
Good Luck.

 

Thanks GreyVF750. Ahh Ignition boxes are on end of rear fender - correct? Are the ignition boxes, CDI and sparking units the same thing just different names? Also, are the ignition boxes on 84 the same as 85-86? or does 84 have a different curve? Thinking 85-86 parts are easier to come by than 84. Thanks you for your help.

 

Yes, yes, should be for the 1000. 750 should be the same or real close to same advance.

 

I switched the spark units (rear fender) and the opposite coil experienced the same cut out at 2,500 RPM.
Having hard time finding unit for 1984. (AKBZ30) 1985-86 units use a different part number. Anyone know if they will work or not? Thank you.

 

The 85/86 model uses a single big box. Try German or uk eBay.
Might also check and see if the 84 VF1000F used the same part number.

 

The part number for the spark unit on the right side of the bike is 30400-MB4-004

The part number for the spark unit on the left side of the bike is 30410-mj4-004

So if it is the one on the right side you should be able to source a replacement off US ebay as they were used on vf1100c and vf1100s.

A cheap pair here
http://www.ebay.com/itm/1983-1986-H...Parts_Accessories&hash=item3cea7ad090&vxp=mtr

 

You could also use a VF750F box temporally. Both 1000/750 have 10* advance at idle. The 750 gets full advance of 37* @ 3300rpm. Where as the 1000 is @ 3800rpm. I would use either 89/93 to make sure 2/4 doesn't get in detonation between 33>3800rpms. Or don't do a WOT/heavy load on motor until 3800rpms. Otherwise the bike will run normal.

This may get your bike back on the road until you can find a 1000 2/4 box.

 

Thanks for all the help guys. I found a 1984 CDI on ebay in London and fed exed it over. Was listed as 1985-86 unit. It pays to look at all the photos. Works like a charm. Back in action. Here's a pic of the guts of the bad box....

 

[video=youtube;5gyqbfbT9SI]https://www.youtube.com/watch?v=5gyqbfbT9SI[/video]

 

Great news. Glad it's going again.