Engine Rebuild Report - Bob`s Megablade Page

Engine Rebuild Report
Donor Vehicle
Honda CBR900RR-N Fireblade
Date of purchase:
31st August 2002
Source:
Black’s Bike Shop, Nr. Ormskirk
Motorcycle Reg No: K265 XXX
Engine No:
SC28E-200XXXX
Chassis No:
SC28-200XXXX
Reg Date:
7th August 1992
Mileage:
25,966
The dealer informed me that the engine was in running order at the time of the
accident leading to the vehicle being scrapped, and that it had been tuned by V&M
Racing to Stage 3. The engine was sold with a 14 day warranty.
Original Condition
The engine had clearly been standing for some time as the casings had become
oxidised. In addition some of the engine mounting lugs had been damaged in the
accident – the lug to the rear of the number 4 cylinder block and the pair of lugs
underneath the rear of the gearbox.
All coolant pipe work and inlet/exhaust ports were plugged with clean cloths. The
spark plugs and sump drain plugs were in situ. The engine oil filler cap and combined
dipstick were missing with the hole plugged with a clean cloth.
Stripdown
The engine was cleaned using degreaser followed by wire brush and metal polish.
The engine was stripped following the procedures in the Haynes manual (ISBN 1
85960 709 8)). The cylinder head was removed, the crankcases were split and the
conrod and piston assemblies were removed. The crankshaft and gear shafts with gear
clusters were removed. All parts were labelled to ensure replacement in the correct
position (particularly important for valve end caps, piston/conrod assemblies and
main bearing shells).
The casings were taken to a specialist aluminium welder for repair. The valve cover,
clutch cover and alternator cover were stripped of the original paint and were
polished.
Examination
It had originally been envisaged that the piston rings would be replaced, with rebore if
necessary, but on stripping the engine down it became apparent from the gasket
sealant used and engravings on the undersides of the piston crowns that it had been
previously been rebuilt. The piston rings end gaps were checked against the
specifications detailed in the Haynes manual and were found to be within the
specified ‘Standard’ tolerances, and well within service limits. Likewise the piston
ring to groove gaps.
Page 1
The cylinder bores were in perfect condition with criss cross honing marks from the
previous rebuild clearly visible. There was no scoring of the bores and no discernible
lip at the top of the cylinders.
Similarly the main bearings and crank journals were inspected and found to be in as
new condition. The little end bearings were also within tolerances.
The clutch assembly was examined. The clutch basket was in good condition. The
pressure plates were in as new condition with no signs of ‘blueing’ or warping. The
friction plates were measured and were well within service limits (See table below).
All clutch spring lengths were within service limits.
It’s a pity that no information on the previous rebuild was available. The supplying
breaker had no details, and in view of the lack of information on the circumstances
and outcome of the motorcycle’s final accident it was considered inappropriate to try
to contact the previous owner. It would appear however that the engine had been
rebuilt relatively recently (in view of the honing marks).
Tolerances
Part
Standard
Tolerances
Service Limit
Measured
Top piston ring #1
0.008 – 0.014”
0.02”
0.012”
Top piston ring #2
0.008 – 0.014”
0.02”
0.014”
Top piston ring #3
0.008 – 0.014”
0.02”
0.013”
Top piston ring #4
0.008 – 0.014”
0.02”
0.014”
Clutch plates
0.115 – 0.121”
0.102”
0.016 – 0.018"
Rebuild
A full gasket set was bought from the local Honda main dealer. This included the
paper gaskets, new cylinder head gasket, new seals for main output shaft and gear
change shaft and new O rings for the oil pickup assembly, oil cooler etc. New
copper/aluminium sealing washers were used throughout the reassembly of the
crankcase. The crankshaft, conrod/piston assemblies and gear clusters and shift
mechanism were replaced and the crankcase rejoined using silicon based gasket
sealant (as per manual). The cylinder head was replaced, all bolts being tightened to
the torque values listed in the manual. Once the cylinder head was replaced the valve
clearances were all checked and were within specification.
The spark plugs were replaced with new items from the Honda dealer, along with new
HT leads, new oil filter and exhaust manifold gaskets. The output flange supplied new
with the Westfield kit was fitted.
The rewelded mounting lugs were finished with a file than polished. The lug at the
back of No. 4 cylinder was drilled out and tapped and the engine was mounted in the
cradle supplied by Westfield. Once in the chassis the engine was filled with oil and
the foam air filter supplied by Westfield fitted.
A length of new HT lead had been purchased from the Honda dealer and this was cut
to length and fitted. Once the bodywork had been fitted the manifold was bolted on
using new original Honda nuts.
Page 2
Parts replaced
All parts were sourced from JT’s Motorcycles, Swansea and were genuine Honda
parts.
9 September, 2002
Sump Gasket
Oil seal - gear change
Oil seal - output shaft
Gasket - cylinder head
Dipstick/filler plug
O ring
Gasket - alternator cover
Gasket - ignition rotor cover
Gasket - ignition rotor cover
Gasket - clutch cover
O ring
O ring
Sealing washers
Sealing washers
Exhaust Gaskets
Oil Filter
VAT
13 September, 2002
£7.05 Sump Gasket
£7.05
£1.55 VAT
£1.23
£6.00
£8.28
£34.13
£8.26
£1.45 1 November, 2002
£10.58 Spark Plugs
£25.52
£4.38 HT Lead
£5.39
£2.35
£30.91
£6.16 VAT
£5.41
£2.26
£36.32
£1.38
£0.94
£5.43
£3.36
£7.04
£102.32
£17.91
£120.23
Grand Total
Page 3
£164.83
Figure 1
Front of engine prior to cleaning and stripping. Significant oxidation later cleaned off
using wire brushes followed by metal polish.
Figure 2
Left hand side of engine showing damage to alternator casing
Page 4
Figure 3
Rear view of engine showing broken mounting lug.
Figure 4
Cylinder head removed. Pistons appear standard, no signs of any bore wear.
Page 5
Figure 5
View (slightly out of focus!) of piston. No significant scoring and discoloration above
rings easily cleaned polished off.
Figure 6
Page 6
Figure 7
Engine now stripped down completely. Inside of crankcase like new, no wear on gear
selector forks or drum.
Figure 8
Crankshaft out. All bearing surfaces unmarked with no sign of any wear or blueing.
Page 7
Figure 9
Figure 10
Crankcase prior to removal of main bearing shells. All shells clean with no wear or
damage.
Page 8
Figure 11
Main bearing shells numbered and checked prior to reinstallation.
Figure 12
Crankshaft placed back in crankcase. Main bearing shells and journals pristine.
Gasket sealant all removed and patency of oilways and galleries checked.
Page 9
Figure 13
Pistons and conrods replaced in engine and crankcase halves back together. New
copper sealing washers visible under bolt heads. Crankcases cleaned and polished.
Figure 14
These casings were all originally finished in gunmetal grey which has been stripped
off and the underlying surface polished. Alternator cover (on right) completely
salvaged without losing ‘Honda’ imprint.
Page 10
Figure 15
Engine now finished and mounted in cradle prior to installation in chassis. All
crankcases and covers polished.
Figure 16
Completed installation in chassis
Page 11
Figure 17
Completed installation with exhaust and bodywork fitted.
Page 12