Motorbike Chain Check: What Honda and Yamaha Manuals Say About Slack and Lubrication

A motorbike chain check comes down to slack and lubrication, and the manufacturers’ manuals put numbers on both, but the numbers differ by maker and model. This article reads four Honda Vietnam owner’s manuals, two Yamaha Exciter manuals and two Yamaha Motor Vietnam articles dated 2024 and 2025, and it sets their figures side by side. None of the pages covers rental bikes, and none gives a weekly check, so the article reports the interval each page states and marks where they conflict.

The Honda figures: slack, a limit and a 500 km row

The Honda Future 125 FI manual gives chain slack of 25-35 mm and says not to ride if slack exceeds 50 mm. The same 25-35 mm appears in its specification and on the bike’s chain label, which reads Điều chỉnh và bôi trơn xích (adjust and lubricate the chain). The manual’s schedule has a row reading “Xích tải Mỗi 500 km” (chain, every 500 km or 300 miles), but the symbols that say whether this means inspection, lubrication or both did not extract. Its pre-ride list says to check the chain’s condition and slack and to adjust and lubricate it if needed.

For a rented bike, report before doing maintenance

The procedures below describe work in particular owner’s manuals; they do not authorize a renter to remove a chain case, adjust tension or lubricate parts. For maintenance, bring the bike to our shop as arranged. If the chain appears damaged, unusually loose or noisy, keep the engine off and contact the shop before riding; arrange safe transport if riding is unsafe. Never run the engine to spin the rear wheel during a chain check, and keep fingers clear of the sprockets and moving chain.

How the Honda manual says to check the chain

• Put the gearbox in N, switch the engine off and stand the bike on its centre stand on firm, level ground.
• Remove the inspection-hole cap and move the chain up and down with a finger.
• Check slack at several points. If it is not the same everywhere, links may be twisted and stuck, and Honda says to take the bike to a Honda-authorised store.
• Turn the rear wheel to see whether the chain moves smoothly. The manual then has the chain case taken off by undoing bolt A and bolt B, the sprockets checked, the chain cleaned and lubricated, and the case refitted with the same bolts (8 N·m is listed); for worn or damaged sprocket teeth it says to have them replaced at a Honda-authorised store.

The manual says the chain must be checked and lubricated thường xuyên, a word that implies repetition but gives no figure, and checked at shorter intervals when the bike is ridden on rough roads, at high speed or with repeated hard acceleration. It also says to take the bike to a Honda-authorised store if the chain does not move smoothly, makes odd noise, or has damaged rollers, loose pins or twisted links.

Slack and interval figures by manual

The figures below are each tied to the model the manual covers; none can be carried over to a different bike.

No page explains why the slack ranges differ. The two Yamaha Exciter manuals list a clutch lever in their indexes, so they cover models with a clutch lever; the T150 text is a first edition of July 2017 and the T155 text a first edition of September 2023, and both say they were printed in Vietnam. The AFS110 manual’s model name is not printed in the extracted text, so it is identified here by its codes. For choosing between bike types, the site has a page titled Motorbike Rental Hanoi: How to Choose the Right Bike.

Cleaning and lubricating: what the manuals print

Honda’s Future 125 FI text says to clean the chain and sprockets while turning the rear wheel, using a dry cloth with a high-flash-point solvent and a soft brush if the chain is dirty. After cleaning, it says to dry the chain and lubricate it with the recommended lubricant, which is chain lubricant or SAE 80 or 90 gear oil if none is available. It does not allow petrol or a low-flash-point solvent for cleaning because of the risk of fire or explosion, says to keep lubricant off the brakes and tyres, and says to avoid applying too much.

The Yamaha Exciter manuals call for a special O-ring chain lubricant in their chart (their cleaning steps say Yamaha or other suitable chain lubricant), applied thoroughly, and say the chain must be lubricated after washing the bike or riding in rain or wet areas. They also say improper slack can overload the engine and lead to chain slippage or breakage.

What the Yamaha Vietnam articles add

Yamaha Motor Vietnam’s 1 July 2024 article names two signs of a slack chain: a clattering noise as the stretched chain hits the chain guard or the underside when shifting, and juddering when accelerating or decelerating suddenly, even at steady throttle. It gives no slack figure; it says that when slack is outside the standard in the maker’s manual the bike should go to a dealer for checking and tensioning, and that the chain should not be set too tight because a very tight chain has no tolerance and can break under high load. Yamaha’s 1 June 2025 article lists “check and lubricate the chain drive system” as step 7 of an eleven-step standard maintenance procedure carried out by technicians, without a mileage or time figure.

Who adjusts and replaces

The Honda manual for the AFS110 codes says chain adjustment needs special tools and should be done at a Honda-authorised store, and its footnote for the chain row says replacement must be done by a skilled mechanic. The Future 125 FI manual text contains the check, clean and lubricate steps but no adjustment procedure. The Yamaha manuals say to consult a Yamaha dealer before adjusting slack. Yamaha’s two manuals print the adjustment steps right after ‘Consult a Yamaha dealer before adjusting’, and Yamaha Motor Vietnam’s 2024 article gives a five-step ‘at home’ tensioning procedure (ring spanner, T10 key) and sends readers who cannot do it to a dealer, while the Honda AFS110 manual says adjustment needs special tools; the pages therefore do not agree on who should adjust a chain. No page says whether removing the inspection-hole cap needs a tool.

What the pages leave out

No page gives a weekly check or mentions rental bikes. The Future 125 FI manual says work done under its schedule counts as the owner’s normal running cost, paid to the Honda-authorised store, and says nothing about hired bikes. For what a scooter’s tool kit may hold and what needs the shop, the site has a page titled A Rental Scooter’s Tool Kit: Identify What Is Present and What Requires the Shop. The slack ranges, the 500 km and 1,000 km intervals and the phrase thường xuyên are not reconciled by any page. Honda’s schedule symbols did not extract, so the manuals read cannot show whether 500 km refers to inspection or lubrication. The Yamaha Exciter manuals give no no-ride limit in the passages read, and the Yamaha Vietnam articles give no mileage figure for the chain.

Sources checked

• Honda Vietnam: Future 125 FI owner’s manual, copyright 2023
• Honda Vietnam: Wave Alpha owner’s manual, copyright 2023
• Honda Vietnam: WAVE 110 owner’s manual, copyright 2023
• Honda Vietnam: manual for codes AFS110MS, MD and MCS, copyright 2016
• Yamaha Motor Thailand: T150 Exciter owner’s manual, 1st edition July 2017
• Yamaha Maldives: T155 Exciter 155 owner’s manual, 1st edition September 2023
• Yamaha Motor Vietnam: chain tensioning article, 1 July 2024
• Yamaha Motor Vietnam: motorbike maintenance article, 1 June 2025

Thuê xe máy Nguyễn Hà is open 09:00–21:00 daily at Ngõ 5 Nguyễn Văn Cừ, Bồ Đề, Long Biên, Hà Nội (near Gia Lâm bus station). Phone: 0334 699 969.