Day 30 - First Ride and Carb Sync

So I've fixed the brake light - it turns out the front brake light switch needed replacing as the internals were very worn and rusted. The rear brake light switch does work fine but the rear pads needed some rebedding into the disc which give the rear brake pedal some extra downward play and making the switch work like it should.

So here's a video of the first ride of the Hornet. I take it for a 20 mile ride which is mostly dual carriage ways and motorway. I keep the headlight on for visibility.

The next problem I had was when I went to start the bike to come back home - the battery was dead already. This led me to check out the rectifier which I subsequently did and found that the ground connection to the frame wasn't great so I cleaned that up.

The rectifier was also proven to be faulty. The manual says to put the headlight on high beam, and then get the bike to 5000 rpm, and the voltage at the battery should be around 13.5 - 15V. I was reading only 12.5 so after testing the stator and making sure that the resistance across the coils was according to specs I went and replaced the rectifier.

When going to sync the carbs, I found that I could only check them and found that they weren't too badly out of sync. The rough idle was in fact due to the fact I had disconnected the pair valve vacuum hose and I hadn't plugged the vacuum hole on the cylinder head. This was causing the rough idle. I only discovered this by accident when I noticed the idle sounded much better with the carb sync gauge hooked up.

Day 29 - Fixing Oil Leak

Now to address this oil leak. Thankfully it's a nice day for diagnosing oil leak problems.

The good news is that the oil leak is not coming from the sump but it's coming from the Oil cooler where the oil exits the engine and goes into the oil coolers and comes back through the filter and back into the engine. Although to fix this I will have to remove the exhaust headers, drain the oil, drain the coolant, remove the oil cooler and replace the O ring seals on the little metal cylinders that connect the oil cooler to the engine block. Thankfully halfords had the right sized O ring seals in stock and I also put some oversized O ring seals to fill in the gap between the oil cooler and engine block for extra good measure.



One thing however, when draining the oil I did notice these little metal shavings come out into the oil. Now I suspect this are from the main bearings and came off during that time I was starting the engine for the first time trying to get it going. I will change the oil again once the bike has done a few hundred miles as I'll have to treat it like a new engine. Thankfully the metal shavings are big so this doesn't worry me too much. I remember reading that even brand new engine will have tiny metal shavings on the first oil change.


However now that the oil leak was fixed I was able to properly fill the cooling system and get all the air out, so I decided to take it for a small spin around the garage just to see if it will ride.

Good news is it rides really well, sounds great and it also feels like it has the power of a 600cc motorbike. Good news. Now to fix other little things as the brake light doesn't work, and the brakes need looking into and I really want to get those carbs synced as the idling sounds a bit on the rough side.

Day 28 - Engine first start

So now all of the engine components have been reinstalled and connected up, its time to hook up a new battery and reinstall the fuel tank and try and fire up the engine. Not forgetting to first fill it up with Engine oil and coolant. 

Here's a video of the whole first start process...

It didn't really go as I had initially hoped but the end result was good. My thoughts on the engine being too tight were correct as initially I had killed the battery just by trying to turn the engine over 3 / 4 times. That was a brand new battery too so I know the engine was way too tight at this point.

After connecting it to the car battery and jump starting it, it took a good number of attempts to get it to fire up, but even though it fired up it didn't want to stay running until a number of attempts later.

I had a couple of theories as to why it took so long to start:

 - The engine was too tight and it took a while for the bearings to loosen themselves up and for the engine oil to start creating a film between the main bearings. The moly grease I used may have also contributed to the tightness of the engine.

- When I first removed the carburettor, I had only drained 1 carb of the fuel and I left 3 of the carbs full of fuel. This may have caused the engine to initially start running on just 3 cylinders until the engine had turned enough times for the 4th carb to refill with fuel - although I may be wrong on this one.

The good news is it eventually started and ran! My attention was immediately drawn to the exhaust leak that was evident from the nasty tapping sound. Thankfully this was nothing serious and was due to the blanking plates I had made up to block off the pair valve holes on the exhaust side - they weren't creating a perfect seal so I used some exhaust putty to properly seal these up.

I also discovered after fixing the exhaust leak I also had an oil leak! It appears initially to be coming from the oil sump! Not good but thankfully not coming from where I had sealed the 2 crankcase halves together - that would have been bad - at least the sump can come off without having to remove the engine. More diagnostics tomorrow...

Day 27 - Carburettor and other components

So with the engine back in the frame the next set of tasks is to reinstall all the other engine components. The next thing to be reinstalled is the Oil cooler along with a nice new oil filter...


The carburettor is next to be reinstalled. I haven't yet performed a full service on the carburettor mainly because I know it was running before with the carbs as they are currently and I just want to see if the engine will run as is. I'm also reconnecting electrics as I go along, and routing them as I put things back in.


After the carburettor the air box is next to go back in, along with the air filter element. There is a K&N air filter element installed so it's probably worth giving that a clean at some point.


Other things have been done like getting the chain back on the engine sprocket, and sorting out more wiring. I've also installed a nice connector for the stator cables as previously this was selotaped together which is big no no...Almost ready to fire this thing up.

Day 26 - Engine Reinstall

So now the cylinder head is back on, valve timing sorted, and valve clearances checked it's time to put the engine back in the frame. I must admit this was one of the toughest jobs to get done successfully. The first challenge was to locate the engine under the frame without scratching too much of the little feet that sit on the oil sump. It was easy enough to get the engine under the bike without the scissor lift, but as soon as I put the engine on top of the scissor lift, it would not slide in as easy as the engine frame mounts got in the way.


Eventually got to the point where I could start lifting the engine up into the frame so the mounting holes align. I ended up having to lift the front of the bike over the engine so that the frame mounts didn't get in the way. My first intention was to get all the frame mounting holes to align perfectly and then start bolting all the engine mounting bolts back in. This wasn't going to work, so instead I got the front left hole to align and then bolted that on individually, and then I messed around on got the front right to align, and with the front of the engine mounted I could continue raising the engine with the lift so that the rear mounting holes would align. After that it was just a matter of putting the mounting bolts back through the engine mounting holes ensuring the spacing collars fit on the correct side, and then done.


It's nice to see the engine back in the frame again. Hopefully a working engine that will start and run! It's still looking pretty bare even with the engine in, so next step is to refit the oil cooler, then oil filter then fill with oil (yes engine still has just moly lube in there and some minor dribbles of engine oil in the cams).


Carburetter has to go back in, then the air box, air filter, and a new battery is needed. Exhaust system then needs remounting and as I'm getting rid of the pair valve completely I need to make up some blanking plates for the pair valve holes on the exhaust side. Still quite a lot to do before I can give it a first start. I've decided before working on other parts of the bike I need to know if the engine will start and run before I work on other things like the suspension and brakes and replace the tyres. Pointless doing any of that if I have to rebuild the engine all over again...

Day 25 - Cylinder Head Reinstall

So now the valves have been sorted out, it's time to put the cylinder head back unto the engine along with the nice new cylinder head gasket that arrived in the post the other day.


Before doing this however I made sure that the engine is at Top Dead Centre, so that helps me get the valve timing perfect.


It's looking like a whole engine again! Just need to reinstall the cams, and get the timing right...


Just a thought, when I reinstall the camshafts I'm going to check the valve clearances to make sure they are within specs. But...before I do this I thought it would be wise to note down the shims that are already in there so I know which shims I need just incase the valve clearances need adjustment.


Camshafts all reinstalled, and time to check if I got the timing right...



That would be a NO! Oh well first time I wasn't expecting to get the timing perfect, but it looks like I need to shift each cam maybe one tooth counter clockwise to get it perfect.





Ok done! Cam timing has been sorted out, all I had to do was remove the intake cam, but left the exhaust cam in place and then I could move the chain over one notch, and then place the intake cam one notch counter clockwise and I turned the engine round manually a couple of times and it feels smooth (although tight) and it goes around nicely! I could even hear the hiss of the compression as it hits the exhaust stroke - it's looking good. I've also checked the valve clearances and thankfully they are all within specs - some are +/- 0.02 out but thats within tolerance according to the manual.


So now it's looking like a proper engine again. I think the next task now is to think about putting the engine back in the bike and then we can start refitting all the other components like the thermostat, water pump, radiator, and so on...

Day 19 - Day 24 - Valve Grinding

So I've concluded that the cranking test I did last was revealing a very weak battery. So I've decided to continue and proceed with the cylinder head service, which now means removing the valves, cleaning the valves, valve seats and that whole area, and it also means lapping / grinding the valves to ensure that they seal perfectly in their seats when they are closed. So time for some grinding paste...



A valve spring compressor is an essential tool for this job. Basically a massive G Clamp which helps to compress the valve spring whilst removing the little cotter pins that keep the spring seat in place.



Valve seat and cotter pins removed, along with valve spring...



I must admit this was a seriously tedious and boring task. Many movies were watched in the background whilst doing this over several days.


Grinding the valve down using a hand lapping tool. Basically you can feel and hear the roughness of the valve as you turn it in your hand, and as you keep going you can hear it becomes smoother and smoother until it sounds near silent. Rotate the valve 45 degrees and do the same thing, keep doing this until it's smooth all the way round. And to do that 15 more times....



A few of the intake valves had this really nasty orange powdery stuff on them, and this was also present in the valve seats - not sure what this was but I cleaned it all out...




Some dirty looking valve seats before cleaning...





And Finally all done with all 16 valves! (5 days later). Most of the time I would do one valve at a time, but then I got a little impatient and did about 4 in one go and laid the valves out neatly so I would remember where everything went when I put it back together.



Now to fit the cylinder head back to the engine...