1986 VFR750 revival ...suggestions

Greetings,

I recently picked up a moth-balled '86 VFR750 that has gone through a couple of people so I really do not have any history on the bike and also have never owned a Vintage V4 so there is a lot that I don't know and will be trying to get up to speed as quickly as a can.

Originally I was just going to see if I could get it running and turn it around but after getting her back on the road I am thinking I will keep it. I had to dig into the carbs to get them cleaned up and all is good there but I am noticing that I may need to get some kind of jet kit and do some fine tuning to get the power curves where I would like them. I have it in the shop today getting a fresh set of Pirelli's so I wont have to worry about an old tire letting go and now can start the fun part of truly getting this bike back into action.

I am hoping this forum and help get me started in terms of some of the "must knows" for this year/model. Can anyone provide some suggestions about known issues that I may want to target first? It is very drivable now but I would like to put some effort into getting it properly jetted but I am sure they must be some other things and more importantly some things may be more critical in terms of my safety (like the brake system). I heard one person tell me about a flawed from brake issue in the master cylinder, does anyone know what he may be talking about? He mentioned something about really small journals that can plug up and result in braking problems.

I will be diligently searching the forums but figured that I would start a thread in case anyone else tries to revive a similar model so I can keep all the important things to check in one post.


Thanks in advance

 

Not heard of a brake problem, but make sure the reg/rec is working.
I have done a Mosfet conversion on mine.
This is a good read regarding the charging system. Its what I have done to my bike.
http://www.triumphrat.net/speed-tri...-diagnostics-rectifier-regulator-upgrade.html

Roger

 

The master cylinder issue he is most likely talking about is not necessarily unique to the bike or master cylinder. There is a tiny hole in the reservoir under a cover that can get easily plugged.

And like artee said, charging system is the potential failure point on these bikes.

 

uNPLUG THE CONNECTOR BETWEEN THE voltaGE regulator and stator (3 yellow wires) to check for discoloration/melting/burning. :distrust:

 

I finally got a day in the canyons with 'ol bessy and it seems the more miles I get on her the better she runs; maybe it just takes some time to get all the cobb webs out? Someone had a 120 front tire on there and when I ordered new tires I didn't realize that we got the standard 110 but I can totally feel a difference in my turning response; much better with the 110 .vs the 120. Not sure if I am crazy or not but the front feels much better now. Went with a 140/70/18 on the rear...

Anyway, I replaced the fuel filter and the fall-off at higher RPM's seems to be gone so I will be taking her out again tomorrow to finish scrubbing off the new sport demons. I have to say that it is hard adjusting my expectations since my last bike was an '06 CBR1000RR but I am learning to appreciate the "character and personality" of the VFR. I love the sound of the exhaust (4-1 Yoshi) and cant believe how this bike draws the "old timers" out of the woodwork. I cant go anywhere without having someone waiting by the bike wanting to talk my ear off before I can leave.

Now that I am driving it regularly, it is behaving much better but it makes me afraid that when I put it away I will have to go through this all over again. No machine likes to sit unused and with too many toys in the garage its hard to keep them all fresh...

With the basic mechanics out of the way its time to starting washing the bike up, I found a ton of crud in and around the chain and rear wheel so I will be working on detailing the bike next.

It is normal for the rectifier to get really hot? I believe that is what is just under the seat (next to the fuel pump), I burnt myself today when I touched it and thought to myself that seems pretty hot?

 

Yeh amazing how the frame holds heat! I would not wana put my dick on it fer sure. How about some pictures of "Bessy?"

You came off a 1000, damn, its kinda like culture shock, you sold that one? Anyway, eace: Welcome aboard

 

lol, culture shock is putting it mildly ...but I can honestly say that I am slowly coming around to appreciating the bike for its era. My greatest challenge is that I have no history with this bike so I do not have any reference to how it should run or feel. I have had many bikes in my day though and am slowly finding my center. I am going to finish stripping off all the old stickers that I don't like and get her all cleaned up and will post some photos up in the next day or two. below is how she was the day to brought her home.

I learned something today that may help others if this is the same across all of these bikes but I noticed that when I parked it, I locked the front wheel and pulled the key out but noticed that my rear light was on? Maybe it is supposed to be an option for an emergency but I put the key back in and noticed that you can pull the key out and it will leave the rear light on or you can ensure the key is turned further to the left and the light will be off. Not sure if my ignition is wonky or if it is a design feature but seems pretty easy to come out to a dead battery if you are not careful or at least aware.

So much to learn about this bike. I have only had her a week and every day there is something new to find...

Here she is the day I got her for $500 (not running). Had her fired up a few hours later but ultimately had to pull the carbs and clean them and replace the fuel and fuel filter to get it street worthy. Will post more once I have her all cleaned up.

one more question, I have two very small buttons on my left hand light switch (one red and one black), anyone know what they are for? I can post pics if they are not standard.

 

Yep, she was somebody's pride and joy once and can be again.

The 750 are a nice size, comfortable, leggy and smooth.

Enjoy. More pics necessary.

Larry

 

sTORAGE-RELATED PROBLEMS wouldn't be likely if you always drain the carb float bowls anytime the bike won't be ridden for more than 2 weeks

How many miles on the $500 WONDER ??

 

23,000 miles

 

Nothing wrong with your ignition; in addition to just locking the steering, there is a "Park" position where the tail light remains illuminated as a safety measure for parking on unlit roads. This will also happily drain your battery if left long enough...

 

Yes, this can be a problem. I simply removed the fuse for this circuit. This allows you to lock the fork without accidently running your battery down.

Typical weak areas are the rectifier as mentioned before. Also check the wiring around the main fuse by the battery. The entire power for the bike will go through a single wire with a spade connector. This connector gets corroded over time and will get hot and start melting the red plug it's in. Make sure it's clean and has a tight fit.

It's also good to pull the ignition switch and clean the contacts in there. Remove old grease and add fresh dialectric grease. This will make the switch feel better and deliver more voltage to the circuits.

I'd also check and clean all the ground wires.

I eventually replaced my main fuse with a new design and fresh wiring along with a newer, beffy rectifier again with new wiring.

 

If the bike is running right you don't need any jetting help or further carb work. Any flat spots are likely related to the non-OEM exhaust, which usually feels a bit weak in the 4500-5000 rpm range with a 4 into 1. Playing with washers on the slide needle may fix it but takes alot of experimentation.

 

About carb tuning, it should have smooth power from idle to mid rpm, then around 5 or 6 thousand you should feel the power ramp up more steeply all the way to red line.

Typically, if there is less restriction on the intake side you need to go with bigger main jets. Like if it has a k&n filter or modded air box for example.

Less restriction on the exhaust side, like a straight through muffler, typically needs the jet needles raised. If you dont space them up with 1 or 2 tiny washers you tend to get a weak spot in power around 5 to 6 thousand rpm. It's still ridable, but you tend to notice when you cruise in 6th gear on the freeway and then open the throttle that you don't take off very fast. It just slowly builds speed till about 7k and then takes off. Once I raised my needles it had great response in the above scenario.

It looks like you got lucky and someone upgraded the rear shock to a Fox unit. The stock rear shock is valved pretty stiffly in general. That shock alone is probably worth $300 to $400 to an 86 owner looking to upgrade.

The stock front springs are pretty weak. If they feel saggy then their probably stock. It's pretty easy to drain the front forks using thd drain plugs and then unscrew the fork caps to refill with either fresh atf fluid or fork spring oil. I added some 3/4" spring spacers to help bring the front end up and have less sag. It will ride better due to the slight increase in trail as well as have less brake dive. I even slid the forks about 1/4" lower to raise the front of the bike more. Raising the front reduces the twitchyness of the bike making it feel more stable.

 

I've thought about replacing that with a circuit breaker while i'm upgrading stuff, any details on your mod?

Got a new reg/rec in the mail from roadstercycle.com, went with the series style after seeing this post with the before and after temps of the stator cover, very cool stuff.
http://www.triumphrat.net/speed-tri...-rectifier-regulator-upgrade.html#post1653685

 

I bought an FH011AA tall fin model from the 04-06 Yamaha R1. It's hidden under the left side tail piece. I took a lot of photos of the install, but I'm not sure I made a thread about it.

Do you want me to post some photos here?

 

That is where i'm considering putting my new reg/rec, should be easy enough. Photos would be great if it isn't too much trouble. I'm more interested in your work updating that main fuse though if you have more info. I've come across a few of your old posts about your mods, always quality and well thought out.

 

I need to get home and look for the pics. I'll post them shortly.

 

Here is a link to a thread I wrote just now. It's got pics of the wire, fuse and rectifier. Hopefully it's good enough as my old photos are not great.

http://www.bikersoracle.com/vfr/forum/showthread.php?p=1561457#post1561457

 

Hell yes, thanks for the pics man. I almost never check that forum but i need to change that habit...