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.

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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.

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Parts replaced All parts were sourced from JT’s Motorcycles, Swansea and were genuine Honda parts.

9 September, 2002 13 September, 2002

Sump Gasket £7.05 Sump Gasket £7.05 Oil seal - gear change £1.55 VAT £1.23 Oil seal - output shaft £6.00 £8.28 Gasket - cylinder head £34.13 Dipstick/filler plug £8.26 O ring £1.45 1 November, 2002 Gasket - alternator cover £10.58 Spark Plugs £25.52 Gasket - ignition rotor cover £4.38 HT Lead £5.39 Gasket - ignition rotor cover £2.35 £30.91 Gasket - clutch cover £6.16 VAT £5.41 O ring £2.26 £36.32 O ring £1.38 Sealing washers £0.94 Sealing washers £5.43 Exhaust Gaskets £3.36 Oil Filter £7.04 £102.32 VAT £17.91 £120.23 Grand Total £164.83

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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

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Figure 3

Rear view of engine showing broken mounting lug.

Figure 4

Cylinder head removed. Pistons appear standard, no signs of any bore wear.

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Figure 5

View (slightly out of focus!) of piston. No significant scoring and discoloration above rings easily cleaned polished off.

Figure 6

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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.

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Figure 9

Figure 10

Crankcase prior to removal of main bearing shells. All shells clean with no wear or damage.

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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.

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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.

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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

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Figure 17

Completed installation with exhaust and bodywork fitted.

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