Triple or Quadruple Bypass Parts List - Honda CX500, GL500, CX650, GL650


This is a parts list of everything you should require at a minimum to complete a triple or quadruple bypass on a Honda CX or GL motorcycle (CX500, GL500, CX650, GL650). For more info on the procedure - and this is a work that's currently in progress - check here.

The David Silver (US) links are broken currently - working on fixing them.

Supplier Abbreviation
Amazon AMA
Bike Bandit BB
David Silver Spares - UK DS (UK)
David Silver Spares - USA DS (US)
eBay eBay
Partzilla PZ
Wemoto UK WM (UK)
Wemoto AU WM (AU)

Cam Chain, Tensioner, Guide

Part No. Part Number Where to buy Notes
Cam chain 1 14401-MA1-013
14401-415-003
eBay, DS (UK), DS (US), PZ All models take the same chain. Do NOT buy used
Tensioner blade, manual models 1 14500-470-751 eBay, DS (UK), DS (US) Only required for manual tensioner models. The O-ring requires dropping the engine to replace so replace it while the engine is out.
Tensioner blade, manual models, reproduction alternative 1 14500-470-751 DS (UK), DS (US)
Manual tensioner bolt O-ring 1 91312-415-000 eBay, DS (US), DS (UK), PZ
Guide blade, manual models 1 14620-415-014 eBay, DS (UK), DS (US)
Tensioner blade, auto models 1 14511-MC7-000 DS (UK), DS (US) Only required for auto tensioner models
Guide blade, auto models 1 14620-MC7-000 DS (UK), DS (US)

Consumables

Part No. Part Number Where to buy Notes
Oil ~4L available should suffice for any model
Coolant ~2.5L available should suffice for all models

Gaskets

Part No. Part Number Where to buy Notes
Front cover gasket 1 11391-449-306 eBay, DS (UK), DS (US), BB, PZ Also called the transmission cover gasket.
Clutch cover gasket 0-1 11372-449-306 eBay, DS (UK), DS (US), BB, PZ You don't have to remove this cover if you are removing the front cover
Rear cover gasket 1 11394-449-306 eBay, DS (UK), DS (US), BB, PZ Thickness critical - 0.8mm required
Pulser cover gasket - CDI 1 11432-415-306 eBay, DS (UK), DS (US), PZ Only required for CDI models
Pulser cover gasket - TI 500 and all 650 models 1 30373-MC7-306
30373-MC7-000
eBay, DS (UK), DS (US), PZ Only required for TI engines
Water pump/impeller gasket See "O-rings" section
Exhaust gasket 2 18291-286-306 eBay, AMA, DS (UK), DS (US), BB, PZ Goes between the head and the exhaust header
Exhaust gasket 2 18392-MK4-000 eBay, AMA, DS (UK), DS (US), BB, PZ Goes between the header and H-box
Exhaust gasket 2 18392-MG7-750 eBay, AMA, DS (UK), DS (US), BB, PZ Goes between the H-box and silencers

O-rings and seals

Part No. Part Number Where to buy Notes
External water pipe O-ring 1 91302-415-003 eBay, DS (UK), DS (US), BB, PZ For 650 motors
External water pipe O-ring 1 91301-MB6-003 AMA, eBay, DS (UK), DS (US), PZ, BB 21.9x2.3 - For 500 motors
Water pump cover O-ring 1 11396-415-000 eBay, DS (UK), DS (US), BB, PZ 127x3 O-ring fits as well, if the OEM part is unavailable
Shift shaft seal 1 91251-ZW5-003 eBay, AMA, DS (UK), DS (US), BB, PZ -
Rear cover water transfer pipe O-rings 2 94608-50000 eBay, AMA, DS (UK), DS (US), BB, PZ 23x2.8mm
Inspection cover O-ring 0-2 91302-001-710 eBay, AMA, DS (UK), DS (US), BB, PZ 27.5mm. One for inspection cover on rear cover, one for front cover. You don't strictly have to replace them but most of them are well and truly flat by now. Note: I ordered three of these and they seem a little small... am looking into whether 91302-001-020 is a more appropriate size
Camshaft oil seal 1 91202-283-013 eBay, AMA, DS (UK), DS (US), BB, PZ 18x28x6
Mechanical Seal 1 19217-611-000 eBay, DS (UK), DS (US), BB, PZ Early engines will require aperture to be reamed out to fit this larger seal
Mechanical seal
Cheaper Alternative
1 11H-12438-10-00 eBay, BB, PZ Yamaha item - like the Honda it's larger than the older bike seals (NLA) so this requires reaming out the aperture to fit if you have an early engine and fits properly with the later 500s and all 650s.
Oil pipe O-rings 2 91301-268-020 eBay, DS (UK), DS (US), BB, PZ Fit under front cover - one above clutch, one on oil pump - DO NOT OMIT - 13.6x2.4
Oil orifice O-ring 1 91306-HB3-003 PZ Don't omit this either! See here for where it should go.

Rear cover

Part No. Part Number Where to buy Notes
Dowels 0-2 94301-10160 eBay, AMA, DS (UK), DS (US), BB, PZ May be necessary if these are damaged/corroded
Gear shift spring 0-1 24623-415-000 eBay (Joe) May be necessary if it gets stretched on rear cover removal

Stator

Part No. Part Number Where to buy Notes
Stator: G47, CDI 1 31120-415-005 eBay, AMA, WM (UK), WM (AU), DS (UK), DS (US) Which is which? - double check what you're getting, particularly on eBay/Amazon/etc.
Stator: G8, TI 1 31120-MA1-005 eBay, AMA, BB, DS (US), DS (UK), WM (AU), WM (UK)

Starter Clutch (Quadruple Bypass)

Part No. Part Number Where to buy Notes
Starter clutch spring 3 28125-516-030 eBay, AMA, BB, PZ, DS (UK), DS (US) Strongly recommend ONLY using Honda springs

Water Pump/Impeller/Cover

Part No. Part Number Where to buy Notes
Copper crush washer 1 90441-706-000 eBay, AMA, PZ, BB, DS (UK), DS (US) -
Impeller cover gasket/O-ring See "O-rings" section
Any corrections, additions or comments are welcome.




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