212-1013480
75cc LIGHT bore-up kit
Ø48mm bore, standard 41.4mm stroke, steel cylinder. Uses your standard head – a low-cost first step.
Services
Tuning for classic Monkeys & small Hondas
For Z50, Z50R, Z50M, ST70, SS50, CL50, Monkey 125 and similar models: more performance, without sacrificing reliability.
Tuning made simple
Tuning can be quite complex and, with so many kits and parts out there, a little daunting. You don't need to have it all worked out. Cliff is happy to walk you through the options and help you get the result you're after, whether that's a bit more pep around town or a proper big-bore build.
Every bike is different, so tuning starts with a conversation and an inspection. We'll talk through how you use the bike – road, shows, paddock or track – and recommend changes that make sense for it. A healthy, well set-up standard engine is the foundation, so any wear or faults are put right first.
We aim for a bike that is quicker, smoother and still dependable. We'll always be straight with you about what a change is likely to achieve, and about any trade-offs in reliability, fuel or road use.
What we can help with
The kits and parts below are just some examples of the common upgrades Cliff fits, mainly from Takegawa and Kitaco. If you've got something else in mind, just ask.
Engine tuning
Careful engine set-up and upgrades, including big-bore kits, cylinder head work and, where appropriate, porting or reboring. Every engine is assessed first so the work suits its condition.
Carburation
Carburettor cleaning, rebuilding, upgrades and jetting to match the engine, intake and exhaust – essential after any engine change.
Exhausts
Advice on and fitting of performance or period-style exhausts, set up together with carburation so the engine runs cleanly.
Gearing
Sprocket changes to suit how and where you ride – better acceleration or more relaxed cruising.
Suspension & handling
Fork and shock refurbishment or upgrades, plus wheel, tyre and brake checks, so the chassis keeps up with any extra performance.
Testing
Every tuned bike is checked and road tested where appropriate before it goes back to you.
Supply & fitting
Kitaco bore-up kits & matching parts
Genuine Kitaco kits Cliff can supply and fit, grouped by engine, with the camshafts, oil pumps and clutch that go with them. Not sure which suits your bike? Frame numbers matter – Cliff will check yours before ordering.
Monkey & Dax bore-up kits
Every bore-up kit for the classic horizontal-engine Monkey, Gorilla, Dax and Chaly (6V and 12V) in one place. Frame numbers matter – Cliff will check yours before ordering.
Early 6V Monkey, Gorilla, Dax 50 & Chaly 50 – Z50J up to frame 1510400, ST50, CF50, CD50
214-1013202
88cc STD Type 2 bore-up kit
Ø52mm bore, aluminium cylinder with cast-iron liner, and a ported big-valve head ready assembled. Power and torque everywhere.
Later Monkey, Gorilla & 12V – Z50J-1600008 on, AB27, Baja, 12V Dax 50
212-1123480
75cc LIGHT bore-up kit
Ø48mm bore, steel cylinder, standard stroke. Works with the standard head.
214-1016420
88cc LIGHT bore-up kit
Ø52mm bore, aluminium cylinder with cast-iron liner. Keeps the standard head for a strong low and mid-range.
214-1083102
88cc NEW STD bore-up kit
Ø52mm bore with Kitaco’s NEW STD big-valve head. Supplied without a cam – pair it with the SPL High Camshaft.
Dax 70 (ST70) & Chaly 70 – Japanese-market only
214-1015420
88cc LIGHT bore-up kit for Dax 70
Ø52mm bore, aluminium cylinder with cast-iron liner, works with the standard ST70 head.
Supporting parts – camshafts, oil pumps & clutch
Camshaft300-1013000
High Camshaft
Revised valve timing for strong, usable power from low to high revs. Fits the standard 6V-era head and Dax 70.
Fits: 6V Monkey/Dax 50 · Dax 70
Camshaft300-1083100
SPL High Camshaft
For 12V-era standard heads and Kitaco’s NEW STD head – pulls harder at higher revs.
Fits: 12V Monkey/Dax 50
Oil pump331-1013300
Super Oil Pump kit
About twice the standard oil flow for kits up to 100cc. Fits Z50J engines up to frame 1805927 – Cliff will confirm for 12V AB27 models.
Fits: All three
Oil pump331-1013400
Ultra Oil Pump kit
About 2.6× standard flow, for hotter builds with a performance head and oil cooler.
Fits: 6V Monkey/Dax 50 · Dax 70
Clutch307-1123000
Manual Clutch kit
Converts the automatic centrifugal clutch to a three-plate manual clutch – ideal with an 88cc kit. Needs a clutch lever and cable set.
Fits: 6V & 12V Monkey/Dax 50
Monkey 125 (JB02) kits
The modern Monkey 125 – see the full fitting details further down this page.
230-1300020
181cc Power Pack LIGHT
Ø63mm × 57.9mm, 11.1:1 compression, with high cam, I-MAP injection controller and O2 canceller. Needs a performance exhaust and Kitaco oil cooler. Race use only.
Clutch307-1444600
Billet Clutch Lifter Set
Hard-anodised duralumin clutch lifter with six reinforced springs (about 60% stiffer than stock) – less slip, more durable. Discontinued; Kitaco’s replacement is 307-1452600.
Fits: Monkey 125 (JB02) · Grom (JC61)
Clutch307-1432500
Reinforced 6-plate Clutch Disc kit
Turns the standard 5-plate clutch into 6 plates for more clutch capacity, less slip and better durability.
Fits: Monkey 125 (JB02) · Grom (JC61/JC75)
Starter758-1432110
Reinforced Starter Motor
Uprated starter for high-compression tuned engines that the standard motor struggles to turn over. Needs a healthy battery.
Fits: Monkey 125 (JB02) · Grom (JC61/JC75) · C125 · CT125 (JA55)
Air filter515-1300100
UNI Filter kit
Replaces the standard airbox to free up room for an oil cooler or catch tank. Includes intake-temp sensor nipple and extension harness.
Fits: Monkey 125 (JB02)
Supply and fitting available. Prices depend on the kit and what else your engine needs – call Cliff for a quote.
Call Cliff · 07903 939229Send a messageSpecifications from Kitaco’s catalogue. Kits above standard capacity may affect road legality and insurance – please check DVLA and insurer requirements.
Monkey 125 JB02 (2018–2020)
Monkey 125 JB02 kit fitting
Have a modern Honda Monkey 125 JB02? Monkey Bike Repairs fits big-bore power kits such as the Kitaco 181cc Power Pack Light, with the same care and attention to detail that goes into our restorations. See the models we cover.
- Fitting of the cylinder, piston and associated engine parts supplied with the kit
- Installation of the electronics supplied with the kit (e.g. injection controller and O2 sensor feedback canceller)
- Advice on any additional parts the kit requires before work starts
Prices & turnaround
Tuning and kit fitting are priced per job: POA / quote on inspection. Kit and any extra parts are bought separately. Turnaround depends on the work and parts availability – Cliff will give you an idea when he quotes.
Performance changes may affect road legality, insurance and MOT. Please check with your insurer and declare modifications. Some parts are intended for off-road or race use only.
Do you have a bike or engine that needs restoring?
For a bespoke quote, call Cliff on 07903 939229 or send an email.