84 VF1000 gear problems????

A friend of mine has a VF1000R. In the first and second gears at about 4-5000 RPM under high load, (wide open) it seems to skip. Not like the clutch slipping, more abrupt than that. Checked the front and rear sprockets and the chain is adjusted right. Any thoughts???

 

Sounds like it's electrical. Test after each "change".

ALWAYS verify your ground and power before trouble shooting electrical problems (remove, clean and diaelectric grease your battery and ground connections).

1. Clean and diaelectric grease all ignition specific connections
2. Make sure the coils have a good ground.
3. Jiggle your ignition key when running to see if you can make the bike miss. The contacts could be corroded.
4. Check your rectifier connection. The wires tend to get hot and melt the connector. (fix is to replace the connector by soldering the wires)
5. Test Coils per the manual
6. Swap Coils and see if the tach moves when the bike skips (one of the coil wires drives the tach)
7. Swap Spark boxes and see if the tach moves when the bike skips.

Before you start replacing parts, run a ground wire to the coil mounts and see if this fixes the problem.

8. Replace In Order and then test after each change:
Battery
Spark plugs (NGK only)
Spark plug caps and wires
Ignition switch
Coils
Spark boxes

 

That's an easy one!

It's almost certainly a gearbox issue (99.9% sure). This is VERY common with the VF's. Pretty much the symptoms are exactly as you describe. I must warn you - some of the parts needed to fix are not available anywhere anymore. I just did this repair on a local guys R and found that out the hard way. It's probably the second gear dogs that are rounded off. If so you can't replace it because that's one of the parts that's not available. The only way to repair is to have the gearbox undercut. That service runs about $375-400.

 

Well up here in sunny Canada, there is a huge bike scrap yard. The last time I was there, they had about 8 VF1000 with engines in the frame and other 4 engines sitting in storage. I thought that might be what it is. Thanks guys.

 

I'd try to grab onto those engines if you can, especially if they are R's. Considering that parts are going to be more difficult to find as the years go on, the parts inside them are priceless. I've sold a couple of engines over the past year or two but I'm not selling any more.

 

Ok..>So if I had the parts....how do I install it?

And what does the procedure look like? Any pics?


regards,

Another Canadian!

 

Well, you really need a Honda service manual. To repair the gearbox you will have to pull the engine and split the cases. Pretty much the same amount of work that it would take to rebuild the engine. It's not rocket science, but if you've never done it before you might enlist someone to do it for you.

 

There is always a first time
duB

 

I was scared the first time...after that....i was all for it!!!!

Hehehe

Jokes aside...then I will try to rebuild it...guy I bought it from told me it was rebuilt...i guess he lied!!

 

BTW Jamie,

What did you mean by having the gearbox undercut?

 

When you say skip, do you mean misfire or it pops out of gear? False neutral is different from clutch slippage or misfire. Try to be more specific in what it's doing. 2nd gear was gone on a 1000F motor I had. Actually it was a clip that separated 2nd from 3rd. Pieces of the clip were in the pan upon removal. Splitting the cases is a pain but not impossible. Don't think of mixing F and R transmission parts. I found out the hard way that the R's gears are wider in some places. I buttoned down the motor and tried to spin the counter shaft sprocket but it wouldn't turn. Took it back apart and put in the F's tranny and there was no problem. I got a tranny on ebay for short money and a fairly cheap gasket kit. With a manual it's not to bad. Try to do it in one day. It's easier to remember how things go back together.

 

Undercutting a gearbox (sometimes called "back cutting") is a performance modification that's done to help the dogs engage better. Historically it's been done for racing where missing shifts isn't just an annoyance but can cause you to lose a race. There is a downside though - the shifting becomes more 'clunky'.

The actual modification takes the square gear dogs and machines them so they look like a dovetail that you would put on wooden drawer sides. This makes a ramp on each mating part which pulls the gears together once they engage. In the case of the early VF's, the machining operation actually cuts the material back enough to make a sharp corner again. This makes the service a repair as well as a performance improvement. It's not real cheap, around $400, but considering that you can't get the parts anymore it's worth every penny.

 

how about i just continue to ride and not push the bike?

it should last a long time and i dont care if i loose a gear?????!

thanks

dave

 

There is a river in Egypt.....what is the name again?

 

I get this question quite often when it comes to gearbox problems. The answer is yes, you can continue to ride it like it is. You will proceed to do more damage to the gearbox, mostly to the parts that already need replaced. The risk is that you will damage other parts in the process as well.

One thing to keep in mind is that it won't last "a long time". I'd say riding it like that would last a couple of months before the gearshift drum locks up all together and you can't shift it at all.

 

Jamie,

Do you have a schematic of the gearbox?

I am looking for an exploded view.

Regards,

David

 

Ask and ye shall receive:

http://www.daughertymotorsports.com/temp/84VFKF_gearbox.pdf

 

You are AWEEEEEEESOMEEEEEEE!!!

 

Shhhhh... don't tell anyone.

 

What scrapyard is that?