XV750 rebuild

**Dr Bob** · 17th June 2004, 11:24

Hi all

I am contemplating getting my XV750 restarted. It has been lying around in the garage for years, and was in need of some attention when I deregistered it. I know that will need to change the tyres, battery, and all vital fluids. I also need to dissassemble the brake caliper ( it only has one ) and master cylinder etc. I have to take the rubber intake boots off and reseal them with silicone, and replace the spark plug leads (they were stuffed anyway). But what I don't know about is the engine. What major work / points do I need to be aware of before I attempt to restart the bike? For All I know I will have to rebuild the engine, but if anyone has a list of things I should check first please post it.

**merv** · 17th June 2004, 12:32

Depends how buggered it was when you parked it up and how you parked it up. If the engine was running well and it had oil in it etc there shouldn't be too much harm done. Maybe just squirt a bit of oil down the plug holes and kick it over slowly a bit first. Then drain the oil, fully service it including well and truly cleaning out the carbs - the fuel dries out and looks like shellack and that all has to be cleaned out especially out of the jets.

**pete376403** · 17th June 2004, 12:37

Worst case: one or more exhaust valves may have rusted open, unless someone stuffed oily rags tightly into the ports or the end of the pipes.
Fuel will have evaporated out of the carbs, leaving either a jelly like varnish or (worse) a white powdery residue blocking up everything. Rings may have rusted to the cylinder walls. Wiring insulation crumbles. Everything made of rubber and exposed to air will be have hardened and will split (seals inside the motor should be all right as the oil (if there is any) may have kept them supple. May be all rusty up in the cam cover/rocker box area due to the oil having long drained away. Sump/oiltank will have a good thick layer of sludge at the bottom. Battery will have curled up and died. Rats will have made a nest in the seat foam.
Apart from that you should be good to go.

Or you may be lucky and find it's not too bad at all. Only one way to find out.

**Dr Bob** · 17th June 2004, 12:40

It was running, but had some electrical issues. The main reason for leaving it at the time was that I was commuting 120k's each way and I didn't want something that would crap out, therefore I bought the much newer (circa 1983) XJ750. I do realise that I have to change the leads etc. and work out the electrical problem.

I don't think that it has moisture in it, never having been parked outside in the last 14 years (I've owned this bike since 1989).

**Dr Bob** · 17th June 2004, 12:43

Originally Posted by pete376403

Worst case: one or more exhaust valves may have rusted open, unless someone stuffed oily rags tightly into the ports or the end of the pipes. ..... linder walls. Wiring insulation crumbles. Everything made of rubber and exposed to air will be have hardened and will split (seals inside ..... of sludge at the bottom. Battery will have curled up and died. Rats will have made a nest in the seat foam.
Apart from that you should be good to go.

Or you may be lucky and find it's not too bad at all. Only one way to find out.

I will have to recover the seat, not because of rats, but just stuffed.

The rubber isn't too bad - not much different to when I bought it; however, I bought it with low k's ex Japan. It must have been stored over there because the owner couldn't get a licence for it. Worst is the rubber between carb and head.

**merv** · 17th June 2004, 12:50

What sort of air cleaner has it got too? My dirt bikes have all been oil soaked foam filters and when they get to about 12 years old the foam just seems to end up looking like wet sawdust and you have to replace them. If you touch the foam it just crumbles in your hand when they get like that. I guess the foam only lasts that long in oil.

**Dr Bob** · 17th June 2004, 12:53

It a paper filter, probably the original one. Woops.

**vifferman** · 17th June 2004, 13:27

Originally Posted by merv

What sort of air cleaner has it got too? My dirt bikes have all been oil soaked foam filters .

So what sort of filter has your VFR got?
Mine had a Unifilter (foam), and it was very good. Cheap to maintain, and easy too.
However they're unavailable for VTRs oddly enough (odd, because the VTR is popular in the US, where the VTR was designed and where Unifilter is based. I contacted them directly and they said they weren't planning to make one yet 7 years after the VTR was released!) Anyway, I made my own. Piece of cake, and only $35 for more than twice as much Unifilter foam as I needed.

**merv** · 17th June 2004, 15:59

As soon as mine was due for a new filter I replaced it with a Uni Filter because you would only get about 1.5 paper ones for the price of the Uni so it was well worth having.

**Dr Bob** · 18th June 2004, 09:18

Well I went home and cleaned it. Sat on it for a short while thinking of how I had missed it so... shit it is skinny - like sitting on a pencil. Took the spark plugs out and they were blackish around the edges and grey in the middle - no signs of rust or corrosion ( they were cleaner than plugs in anything else I own ). Hooked up the jumper leads and turned the bike over - no problems, it actually sounded quite good. Then I put some oil into the cylinders - I thought that if anything was seized I would like to know about it. And there was a spark - but it was really weak, I think I remember this is why it was running so rough. I've gotta get some parts, and then I will get serious. BTW when I said it was years, I figured it out yesterday, it has been about 7 1/2

**FROSTY:Me** · 18th June 2004, 10:02

Before ya go lashing out big money try cleanin electrical contacts and cutting 12mm off the end of plug leads. Long shot but it can be all ya need

**Dr Bob** · 18th June 2004, 10:08

I checked the odo last night too. For a bike that was born more than 20 years ago, it's kinda fresh - 61,000

**Posh Tourer :P** · 18th June 2004, 10:41

Originally Posted by Dr Bob

And there was a spark - but it was really weak, I think I remember this is why it was running so rough. I've gotta get some parts, and then I will get serious. BTW when I said it was years, I figured it out yesterday, it has been about 7 1/2

If you want a hand with any electrical stuff I may be able to help...Had an MZ with electrical problems, a Honda with 6V battery (ugh - but made it run ok..) and did a full install of electrics on the beemer including converting it from twin coil electronic ignition to single coil points box because it would be cheaper to service....

I would like to think I have some idea on bike electrics, but I'm certainly no auto electrician....

**Dr Bob** · 19th June 2004, 12:21

I am in a similar boat, have always seemed to manage to fix the issues when they arise, but the biggest problem is often finding the issue. I have an intermittent short somewhere on the XJ and it is has been a bugger to find. No chance at the moment because it isn't playing up.