Keeway RKS125 - Starting and revving problems

[Zippiii]

I have a 2018 Keeway Rks 125cc since since August 2020, for the past 3-4 months I’ve been having to bump start the bike and when doing so whilst using full throttle it limits itself to 3500-4000 rpm but after some time closing the throttle it does the full range. I have had the wiring “TEMPORARILY” fixed. I’ve put 3 different battery’s which different power outages but it will NOT tick over. I have a mechanic who is currently working on it now but he is wanting to find the solution ASAP rather than checking everything until a dead end.
If you have any suggestions what it could be I can run by them with him to see if he’s done that already. If you DO have anything please think about, if that didn’t work what else could until it can’t be fixed any further.
I’m struggling to find someone to contact who’s specialised in keeway to get suggestions so if you have a number or email please comment it.
I will still be looking for number and emails myself just need a hand.
Thank you for your time,
Connor

[bikenut]

Exact model please, exact as in exact model !
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nuts about bikes

[Robby]

Having to bump start it, wiring "temporarily fixed", 3 batteries, and it won't tick over.

So electric start isn't working, it won't tick over. I'm assuming it's also generally quite fucked, was it a £300 bike?

Start off by checking the charging circuit and sorting out the wiring. If it is still misbehaving once the wiring is sorted, look at the fuelling side.

[Easy-X]

There's nothing special about a Keeway it's Yet Another Chinese 125. They are not complicated and, how shall we put it, a homage to Jap bikes of the 80's.

If the mechanic is fucking you about just find another mechanic. Too little information to go on to give you any easy answers
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Fat Angry Scotsman]

[Easy-X]

[ThatDippyTwat]

Moto GB are fucking useless at getting parts. I have an RKS. GS/GN/GZ clone 125 motor. 18 platers were EFI IIRC.

Have they check the valves? Mine ran like dogshit until they were done. Aftermarket startermotors are weak, if you have one make sure your battery is actually capable of turning it fast enough, just seeing 12v is not a decent enough check. Clean the air filter, and make sure the throttle and choke cables are lubed and travelling the full range.
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'98 VFR800 (touring) - '12 VFR800 Crosrunner (Commuting) - '01 KDX220 (Big Green Antisocial Machine)

[Zippiii]

I have been told by my mechanic that the compression is at 70psi where my bike needs around 116psi, he has checked the fuel, spark and air. They all came back fine but the compression. He suggests that I will need to get a piston kit to be able to fix the bike but it will cost about £300 ish, plus I have other cosmetic problems with the bike as I’m a new rider which will make it cost about £500 to make it pass its MOT due in a few months. He suggests that I either do that or get a new bike with the money I don’t have or get another job close by and get a new bike in a few months.
I’m still paying off this bike and I don’t have any money so I haven’t got many options to go off...

[Fat Angry Scotsman]

[Robby]

If you have more time than money, get the haynes manual for Chinese bikes and fault find it, then fix it yourself.

Compression loss is down to either a problem with the piston/rings/cylinder - which gets fixed with a top end kit - or by the valves not sealing. It could be as simple a fix as checking and correcting the valve clearances, which is routine maintenance. The haynes manual will tell you how, and the only tools needed are a couple of spanners, pliers, and a set of feeler gauges. Very cheap tools, in fact everything but the feeler gauges should be in the bike toolkit.

Likewise, if it does need a top end kit, the parts should only cost about £100, and it isn't a difficult job if you follow the manual step by step and don't skip anything. The most tedious jobs are the most critical, like scraping off old gasket material, cleaning things, and setting the timing properly.

I'm wary of anyone suggesting a top end kit to fix a 4-stroke bike. 4 strokes should not be wearing out the top end. Cylinder wear should only occur if the mileage is very high (50k miles+ in your case), or if the engine has been run with low/no oil for an extended period - in which case everything else should be fucked too. It is possible that the rings and cylinders are so poorly made that they are wearing out, but seems unlikely.

Alternatively, is it still covered under any kind of warranty from the place you bought it from? It sounds like a shit bike. Good to learn how to fix bikes, but not something to pour money into if you're paying a mechanic to do the work.

[Nobby the Bastard]

It does sound like the valves are slightly open until it warms up.

If they are too tight when cold it will be hard to start and there would be shit compression. As it warms up the valve stems will expand at a different rate as the head and close up properly. It'll then work properly.

The difference in temperature needed will be enough caused by it firing badly whilst bump starting. I bet you can kick it easily after you bump it into life.


Check the clearances.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Easy-X]

From my short period on a Chinese 125 I can attest that valve clearances can go out relatively quickly, maybe less than 6 months of normal riding. Conversely they are dead easy to check and adjust if you have desire to do some minor maintenance.
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Robby]

Also worth noting in case it wasn't blindingly obvious, even in good running order that bike (and most bikes like it) will need very frequent maintenance. Oil change interval for instance is likely to be around 1000 miles, or every 1-2 months for most people commuting.

Most of this maintenance is quite routine and simple. It will take a while the first time you do it as you follow the steps in the book, but you will get quick and competent in no time.

Alternatively, taking a 125 to a mechanic for all this would get very expensive, very fast. This is why a lot of 125s either have poor maintenance history or evidence of a lot of cock-ups and bodges. People want them to be cheap transport, and use them to learn on.