My Megabusa - trials and tribulations [update end p2]

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SteveRST
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My Megabusa - trials and tribulations [update end p2]

Postby SteveRST » Wed Jun 26, 2019 5:42 pm

Thought I'd start a blog-style topic documenting the latest round of 'issues' with my Westfield Megabusa turbo and my cack-handed attempts to fix them.

The 2019 Eurotour to the French Alps a few weeks ago was truly excellent, but my car returned with several issues:
- battery not charging - charging system outputs ~13.2v when cold, but drops away to nothing when engine is hot.
- diff leaking - oil leak coming from pinion oil seal at diff nose.
- 6th gear AWOL - half-way through the tour I went for an unremarkable gear-change from 5th to 6th and just got a lot of noise, banging and knocking... but no drive. 6th gear had disappeared has remained completely elusive since.

So, considering I know almost nothing about bike engines, gearboxes and charging systems, I decided to get my hands dirty and give it go.


First job - while engine is still running - is to diagnose the non-charging battery...

I didn't really know this before, but motorcycles have a less integrated charging system than cars. The bike has the generator part of the system inside the engine. The rotating part of the generator is driven by the engine, and the fixed part is called the 'stator'. The stator generates AC voltage on 3 phases (3 wires). These exit the engine and provide a separate component, the Regulator/Rectifier, with AC voltage which it converts to ~14v DC output that can charge the battery.

So there are two components that could have failed; the Stator or the Regulator/Rectifier.
Now, when I was having issues in France, the garage there did a few multimeter tests and declared that the Stator was FUBAR.

Obviously, I wanted to try and confirm this myself. With the help of a Hayabusa Service Manual [thanks Google] and a multimeter, I went about testing the Rectifier which seemed to pass all the resistance/diode tests - good stuff.
Next to test the Stator - I did resistance test between each of the three phases and these seemed a little higher than spec but not much. Then to test AC voltage output of each of the 3 phases... first two were OK at 20V at idle but third phase showing only 4V. You are supposed to test this at 5k revs and see around 70V on each phase, but to be honest that would have been too noisy and I was happy to accept the low reading on one phase at idle and the opinion of the garage in France, and declare the Stator 'Dead'.

Now the fun starts! The engine has to come out to replace the Stator and to diagnose the gearbox issue...

Car lifted on to stands and ramps. Oil and coolant drained. Front body panels removed... really easy with the detachable side panels!
01.jpg


Chassis brace and turbo has to be removed, after disconnecting the turbo oil supply and oil drain hoses.
02.jpg


Opted to keep the exhaust manifold attached. It's a tight fit to top chassis rail, but I think engine will come out with it attached.
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Turbo unit doesn't have come apart to remove it.
04.jpg


Lots of wiring to remove on this side. Unfortunately the main loom had been fed between engine and engine cradle and so the front loom had to stripped back to the bulkhead. I opted to snip the lighting wiring and will wire up connectors when I put it back in.
05.jpg

06.jpg


Dry sump tank removed to allow more access, and to allow me to drain it properly and clean it out.
At the back of the engine the prop shaft was unbolted as well as disconnecting oil scavenge pump feed and the brake slave cylinder connection.
At the front of the engine, the oil inlet from Dry sump tank was disconnected as well as oil pressure gauge hose and oil pressure warning light switch wire.

Engine is mounted to an upper engine cradle which is bolted to the top of the chassis, as well as a smaller lower engine cradle which is bolted to the lower chassis. The engine was unbolted from the cradle which stays in the car. However, the upper cradle should be removed with the engine so that was unbolted from the chassis without drama.

Engine lifted with inlet manifold and plenum still in place. Lifting straps around the upper engine cradle and engine mounts. Came out pretty easy.
07.jpg


Engine on the bench, with upper engine cradle still attached.
08.jpg


Empty space. Needs a clean!
09.jpg


Engine on the bench. Now to make something to be able to mount this thing to a Clarke engine stand.
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11.jpg


More to come!
Last edited by SteveRST on Thu Aug 15, 2019 10:32 am, edited 1 time in total.
Westfield Zetec turbo & Westfield Megabusa turbo

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Tony B
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Re: My Megabusa - trials and tribulations

Postby Tony B » Wed Jun 26, 2019 5:50 pm

Fantastic, looking forward to this write up - like you I know bugger all about bike engines and I’m horrified by the thought of it breaking down in the alps, I’d hate to think my first choice will be the recovery truck!!

Keep the updates coming!

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Re: My Megabusa - trials and tribulations

Postby SJLB » Wed Jun 26, 2019 7:04 pm

Good work Steve.
I too had charging issues with my Busa, there is a common fault with overheating at the connector between the rectifier and the loom. Mine burnt out so I soldered the connections, then the next connector where the loom meets the battery lead at the starter solenoid burnt out so I've now wired the stator straight to the regulator and then straight to the battery and have had no issues for about a year. I also located the rectifier in the nose to keep it cool. I'm sure your stator diagnosis is correct and as soon as you open the cover you'll know, but do check all the connections too. Can't help with the gearbox though, sorry!
Steve
Westfield Megabusa, Bromley, Kent.

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Re: My Megabusa - trials and tribulations

Postby greenwoo » Wed Jun 26, 2019 8:42 pm

oooh fettling, keep it coming Steve, fair play for diving in.,...

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Re: My Megabusa - trials and tribulations

Postby locost220 » Wed Jun 26, 2019 8:49 pm

Well done Steve, watching with interest.
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SteveRST
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Re: My Megabusa - trials and tribulations

Postby SteveRST » Thu Jun 27, 2019 11:22 am

SJLB wrote:I too had charging issues with my Busa, there is a common fault with overheating at the connector between the rectifier and the loom. Mine burnt out so I soldered the connections...

Hi Steve,

Thanks for your reply and advice. We noticed a burnt out rectifier > loom connector when we were at the garage on day 1 of the France tour...
burnt-connector.jpg
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The first thing the guy at the garage did was to replaced the connector (for free!) but the problem persisted.

The stator > loom connector looked fine, but I think I'll do what you have done and eliminate these by soldering the connections instead.
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Re: My Megabusa - trials and tribulations

Postby SJLB » Sat Jun 29, 2019 4:35 pm

Come on Steve, let's see the gearbox then!
Doesn't take that long to split the crack case, or should we send Matt or Rich over?
Steve
Westfield Megabusa, Bromley, Kent.

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Matth93
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Re: My Megabusa - trials and tribulations

Postby Matth93 » Sun Jun 30, 2019 7:21 am

I have a big hammer that will split it for you, although it might be in more pieces than expected :lol:

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Re: My Megabusa - trials and tribulations

Postby SteveRST » Tue Jul 02, 2019 5:23 pm

I wanted to get the engine mounted up to my engine stand, rather than messing about trying to dismantle stuff on the bench. Couldn't see anything I could buy off the shelf in the UK, although company in the US does sell this for US$105...
12a.jpg
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Got some inspiration from that, and went to B&Q and bought two 90 degreee 3mm steel brackets for £4.50.
Measured and cut the brackets, then got out the Aldi welder and vaguely welded (I'm a newbie!) the two brackets together.
13.jpg


Drilled holes to fit supporting pins and finally a bit of wood (added lightness). I'm pretty happy with my Busa engine support bracket for under a fiver.
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Gave the engine a good clean with degreaser.
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Removed the SBD sump. Still no flakes or pieces of metal - a good sign!
17.jpg


Stator cover and Stator removed. Not sure if you can tell if a Stator is knackered by looking at it? But this one looks pretty poor... looks rusty?
Hopefully a new one will solve my charging issue.
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19.jpg


Removed the Dry Sump Scavenger Pump and the hydraulic clutch Slave Cylinder.
20.jpg


Other side of the engine... Removed the clutch cover, starter clutch cover and starter motor cover.
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Clutch on the bench. Motorcycle clutches are weird... run in a bath of oil.
22.jpg


Removing the bolts which attach the lower crankcase to the upper crankcase. There are loads of them! 7 of the top and 23 bolts on the bottom! 30 in all!
23.jpg


For the bottom crankcase bolts, I numbered their location on a plan in the manual, with corresponding numbers on a piece of card so I can put them back in the right place.
24.jpg


With a bit bit of persuasion and gentle leverage the casings came apart (There on points on the casings which allow you to apply leverage to each half of the crank case without damaging the aluminium sealing face.)
Final thing was to remove the gear position sensor so that casings could be separated fully.
25.jpg


So what's inside?!
I've made a little video of that... will upload soon!
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Re: My Megabusa - trials and tribulations

Postby Wingco » Tue Jul 02, 2019 6:37 pm

Fantastic write up Steve, you certainly get stuck in, fingers cross for you and you sort your problems out very soon.
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