1988 vs1400 engine problem?.

[kiwi cowboy]

I just bought a bike as above off trademe.
Guy I rang about it said it ran a bit rough but had been in storage for 2 years but started good with new battery.
Bike has done 30,000 miles.
I got it home and started it to find it is only running on front cylinder.
I put another plug in rear cylinder and it then ran on both but as it warmed up it started blowing smoke out the muffler on that side and smoking out the header muffler join.
All this smoke disappeared after a short run down drive so changed the oil and redid fork seals.
The bike was on blocks for 4 days while doing fork seals and after getting it back together it wouldn't start winding the battery flat.
I charged the battery and it started but only on the front cylinder with the rear cylinder cutting in firing as the motor warmed up but then started smoking badly again for a while.
Just took it down drive and even after the ride short as it was it is still smoking out the header/ muffler join with iol smoke smell.
When I picked it up I noticed it had a small leak I thought was the head gasket slight leak but turned out it was coming out the motor/ header join.
I didn't meet the seller (got nefew to pick up) but have been in contact with him about this.

What are the possibilities of what could be wrong?

Rings in rear cylinder ( but that would make smoke all the time?)
Valve guide seals cracked?.

Any ideas from anyone?.

[OddDuck]

Ohh boy where to start... it's a 1988 bike so is now 28 years old. Metal parts like rings, valve guides etc are probably still OK unless high mileage but seals like valve stem seals may not be, unless the motor was rebuilt at some time. It's also presumably been stored in an unheated shed or garage, meaning that cold and humidity will have led to water ingression into any high voltage insulation. This is fixable btw.

Right, here's a few ideas:

Compression test. This'll quickly check valve seating / rings condition together. If returning a low value then you'll have to work out if it's rings or valves. You can do a rough comp test with a finger against the spark plug hole, just make sure you've grounded the spark plug or are using the kill switch.

Check air filter against bad sealing or holes. A hole as small as 2mm can be enough to lean an engine out. If in any doubt whatever, filters are cheap, get a new one.

Check the spark plugs. If they're coming out covered in oil (wet black) then like it or not it's serious engine work time, if you are very lucky it is only the valve guide seals. If they're coming out covered in soot (dry black) then the bike's running rich enough to foul them and you'll lose spark across the blacking.

Check the petrol. How old is the gas? (It does go off)

Check the fuel delivery - pull the fuel hose off the carb, open the fuel tap or run the fuel pump (I'm not familiar with the bike sorry), make sure that fuel is being delivered. Expect gas spills, keep a bowl handy.

Check the fuelling system. I'll assume carburettion, check float heights and condition of jets. Check for rust flakes in carb float bowls by draining into a stainless steel pan (an old kitchen bowl is ideal). If you see rust then that could be blocking the jets. Check the bellows. A pinhole leak is enough to upset them, if they're old bellows then it's usually a good idea to replace them if you have the carbs apart.

Check earthing points through the entire bike. Clean any rust or oxidation off, use new fasteners, make sure it's clean metal to metal contact.

Check connectors on the wiring harness, go looking for green rot on wires or spade lugs. Pull apart and refasten as many connectors as you can, including the main relay. The make and break action wipes the metal surfaces clean. Do this one connector at a time only, you don't want to end up not knowing what goes where. Particularly check the connectors to the CDIs and the coils.

Pull ignition coils and CDI off, then put them into a warm, dry environment like the hot water cylinder cupboard for a few nights. While doing that, check the rubber insulation on the HT leads - if any cracks or degradation shows, they're stuffed and have to be replaced.

Some of these are easier than others sorry, things like stripping the carbs down and checking jets and bellows are real last resorts.

Hope this helps.

[kiwi cowboy]

Ohh boy where to start... it's a 1988 bike so is now 28 years old. Metal parts like rings, valve guides etc are probably still OK unless high mileage but seals like valve stem seals may not be, unless the motor was rebuilt at some time. It's also presumably been stored in an unheated shed or garage, meaning that cold and humidity will have led to water ingression into any high voltage insulation. This is fixable btw.

Right, here's a few ideas:

Compression test. This'll quickly check valve seating / rings condition together. If returning a low value then you'll have to work out if it's rings or valves. You can do a rough comp test with a finger against the spark plug hole, just make sure you've grounded the spark plug or are using the kill switch.

Check air filter against bad sealing or holes. A hole as small as 2mm can be enough to lean an engine out. If in any doubt whatever, filters are cheap, get a new one.

Check the spark plugs. If they're coming out covered in oil (wet black) then like it or not it's serious engine work time, if you are very lucky it is only the valve guide seals. If they're coming out covered in soot (dry black) then the bike's running rich enough to foul them and you'll lose spark across the blacking.

Check the petrol. How old is the gas? (It does go off)

Check the fuel delivery - pull the fuel hose off the carb, open the fuel tap or run the fuel pump (I'm not familiar with the bike sorry), make sure that fuel is being delivered. Expect gas spills, keep a bowl handy.

Check the fuelling system. I'll assume carburettion, check float heights and condition of jets. Check for rust flakes in carb float bowls by draining into a stainless steel pan (an old kitchen bowl is ideal). If you see rust then that could be blocking the jets. Check the bellows. A pinhole leak is enough to upset them, if they're old bellows then it's usually a good idea to replace them if you have the carbs apart.

Check earthing points through the entire bike. Clean any rust or oxidation off, use new fasteners, make sure it's clean metal to metal contact.

Check connectors on the wiring harness, go looking for green rot on wires or spade lugs. Pull apart and refasten as many connectors as you can, including the main relay. The make and break action wipes the metal surfaces clean. Do this one connector at a time only, you don't want to end up not knowing what goes where. Particularly check the connectors to the CDIs and the coils.

Pull ignition coils and CDI off, then put them into a warm, dry environment like the hot water cylinder cupboard for a few nights. While doing that, check the rubber insulation on the HT leads - if any cracks or degradation shows, they're stuffed and have to be replaced.

Some of these are easier than others sorry, things like stripping the carbs down and checking jets and bellows are real last resorts.

Hope this helps.

Thanks OddDuck.

I think the leads look good and haven't had the carbs off yet but have had them off and cleaned out on all the 4cylinder bikes I've had so not scared to get into that if I need to.
The rear cylinder plug I pulled when it first arrived was black dry sooty which makes me lean away from a ring problem and more towards a guide seal in the exhaust valve which is what I meant in my original post regarding valves.
If it was leaking past the exhaust valve guide It could get blown straight out the exhaust then durning off as it heats up in the header?.
If it was the inlet valve guide seals leaking that bad I would have thought it would have wet the plugs or be blowing smoke all the time like a two stroke as it would if rings were buggered?.
Will try and get a compression tester from some where to test.

[OddDuck]

Black dry sooty is fuel mixture - running too rich. If it was black wet sooty it'd be oil.

This is good news, your rings / guides / guide seals are probably fine.

At this point I'd suggest stripping the carbs and looking for crushed rubber / bowed caps / pinholed diaphragms / worn needle and emulsion tubes.

[kiwi cowboy]

Black dry sooty is fuel mixture - running too rich. If it was black wet sooty it'd be oil.

This is good news, your rings / guides / guide seals are probably fine.

At this point I'd suggest stripping the carbs and looking for crushed rubber / bowed caps / pinholed diaphragms / worn needle and emulsion tubes.

Yer well pulled the plug this morning after it wouldn't fire on rear cylinder and it was wet black so am going to strip rear carb first and clean as it pops out of that cylinder at idle which could mean lean on pilot jet and blocked too.
I need something to do to keep me out of the wifes hair anyway.