DT125R FORUM

Not a good weekend for projects sadly.

Today felt like a good time to tackle the the gearbox rebuild.

Input shaft stripped ready to lay the gears onto the 1st gear conversion.

All rebuild, new bearings, shims and circlips.

So far, so successful.

Next tackling the output shaft.

Was going extremely well...until it came to dismantle third.

This was not coming off and the prognosis wasn't good. Rough running third gear with swarf coming out of it.

The layshaft's damaged beyond repair and so was third gear.

Luckily the layshafts can be had brand new and I managed to find third gear.

So sadly that's the cost of a used gearbox, but then that tells me for scrimping on the gearbox.

The layshaft's coming from Japan so I'll have to park this rebuild for now.

Forum software patched and server upgraded.

Any problems let me know.

Cheers,

Calum

Took the bike on my first little outing to the Forest of Dead yesterday to the Cotswold Biker Nite.

Saw this GAWGEOUS Honda NS400R

Didn't know these were even a thing and it was utterly stunning in the flesh.

Was extremely quiet as it set off down the road.

@MadGyver

It's not my thing, I am not sure I would have gotten one if my Dad wasn't massively into them. But I do get it, they're fun to ride.

It's a shame you can't get any viable options though, but I'm pretty sure the bottom ends are all the same, so if you can get the 125, you'll easily be able to slap on a bigger bore to get a few more ponies.

This rides pretty well to be fair, seems to pull well for what it is.

Last week I took ownership of a new motorbike for my collections

It's a 1979 Piaggio Vespa Douglas with a Malossi 210cc kit and a full nut and bolt restoration. I mainly bought it as it's registered as a historic vehicle and as such is now MOT and Tax exempt, and the cost to insure was peanuts so it's basically ready to ride and enjoy.

It was built in 2019 and used at the local meets for a few years, so it has the odd blemish here and there, but overall it's in mint condition.

This was purchased off my Dad who, in recent years, has gone absolutely scooter bonkers.

He bought a brand new Piaggio Vespa shell in 2019 and replaced the original rotten shell.

This isn't concourse, it has lots of great mods on it, like modern front suspension and brakes, SIP digital speedo and SIP Road 2 exhaust.

I've never ridden a scooter before, but I actually really enjoy it. I enjoy the simplicity and the basicness of it. The four speed gearbox has tripped me up a few times and its quite sketchy having it on the handlebars, but is quite rewarding when you're nailing it through the gears.

I don't need any more projects on the go, although I would also like to modify this in years to come, but for now it's good to have a bike that someone has done all the work to and is basically ready to ride.

Any scooter fans out there?

You'll want to understand why that's happened before restarting the bike.

Lack of oil, incorrect piston ring end gap tolerance, or just generally tired engine, etc.

@YYHpilo Mick Abbey will rework the head for you, used to charge £30, but last time I used him he said he was going to have to up his prices.

@YYHpilo Yeah that's too low. There is something wrong with the engine and it needs dismantling and investigating.

The 3RM CDI, to my knowledge is supposed to be pretty good. Could always look into the ignitech CDIs to see if they're a bit cheaper.

I wouldn't have thought machining the head would result in any necessary changes to the ignition curve. You should be fine as it is.

Obviously, an aftermarket CDI is going to allow you to tailor the bike better.

Yeah that looks like the head gasket.

Did you dip your fingers into the neck?

A compression test would tell you for sure as it'll be down on compression. But this is an indicator.

A compression tester is like £20.

https://www.ebay.co.uk/itm/167499985920?_skw=gunson+compression+tester&itmmeta=01JTP74TSF0N5BEDMP9VBQ7WCM&hash=item26ffc6f400:g:BXwAAOSwlhpoG3Cl&itmprp=enc%3AAQAKAAAA0FkggFvd1GGDu0w3yXCmi1fRWRe%2BDCnd%2Fv8ASPfYcwl4Qwe6G9UQ%2FUi8k0py2nze%2BaGESUbULwGf1He2oKCL4P8mfShHgcCAe7A1bXkgaijR5TEPPfOrSIvrYmzQb3dM8BDgU8JU5FDDAdAElgJH%2Fakz8RdSeFQARHDfao8VgDAERcjm9Z5MdcFSwi%2B6DHnh%2FdqVr4uDakoIcpV%2FQ5HjmuEEjfgpDcOQSxz7isQI7MNl1c%2FWpDDQSvpDTxjmFclGOKUCTbPqjBKAKGnqb6VjXBg%3D|tkp%3ABk9SR4Ctk8fVZQ

Well worth getting one.

@Calum said in Bike no longer starts help:

What's the mileage on the engine? What's the health of the engine? Have you got a compression tester to check?

Has the head gasket blown and you're leaking coolant into the engine. Stick your fingers into the radiator cap and check for the presence of any oil residue.

oil

What's the mileage on the engine? What's the health of the engine? Have you got a compression tester to check?

Has the head gasket blown and you're leaking coolant into the engine. Stick your fingers into the radiator cap and check for the presence of any oil residue.

This symptom sounds like the reed switch, but I've never had to derestrict one myself.

Have you got a compression tester to check the engine's health?

The easiest way to derestrict these bikes is to simply get an aftermarket CDI and then you don't have to worry about the reed switch.

Managed to source OEM indicators/mirrors (although not my taste personally).

A fair chunk of change was dropped on renewing brand new OEM NOS throttle, clutch, choke, Odometer cables.

I also decided to paint the mild steel arrow pipe. Just make it look like a factory pipe and nothing fancy.

I must have bought this pipe brand new 3 years ago and it's been in storage since and even then it's rusting....

It's no TYGA pipe for sure!

Buzzing to get this bike complete though.

Normally, they just add a throttle stop to restrict the bike, so you can only open it 3/4s of the way.

This is what a lot of the test centers do as it's easy then to unlock the bike to full power afterwards.

@glynn6500 oohh, yeah very hard to source.

@scrimsmustang is a bit of a legend for finding things as well as @oldman IIRC.

Your best bet is CMSNL from what others have said they are Wizards!

Finally!

Actually found some time to go out on this thing!

The original gearing I bought for this was a no-go and I ended up chucking it in the bin.

Instead, I found a Trail Tech crankset made for an E-bike, had to swap out the bottom bracket, but the result is something which gives me the ability to go up a few teeth on the front (currently rocking 24t), blitzes up moderate inclines, but lacks real top end.

I managed my usual route easier than the 26er, both up and down hill. It just felt like it handled the rocky sections better than the 26er, the lower gearing made it easier to climb some of the hills I had to get off and push, overall I'm very pleased about how this one has turned out, hopefully get a lot of use out of this over the coming years.

@fishy-fish I'll put money it's that then.

Piecing it together bit by bit.

Got some Ferodo brake pads for the rear caliper.

Wiring loom gently fitted, I think this is where it goes.

The original ignition barrel was ropey as f. Clearly non-genuine and been replaced before. This gem came up new old stock genuine, so snapped at the chance to get it.

Just focusing on the front end at the moment. Got some genuine wing mirrors from Italy winging their way to me.

Hi there,

It will be very unlikely to be the magneto as the bike runs off the battery and the output from the stator is rectified to 12V.

Based off of your very basic description, some of the common pinch points are:

• Faulty battery
• Faulty wiring
  • Check ignition barrel leads to loom
  • Side Stand Switch
  • Kill Switch
• Poor/Aftermarket Ignition Coil
  • I've had this problem myself with a Chinese Ignition Coil which basically resulted in the bike running great from cold, then once it warmed up the ignition would die above anything from 5k onwards
  • Replace with genuine 3RM Ignition Coil

I am sure there are lots of reasons, but since you've only given a sentence to go by the above should do for now.

Don't forget the Search function as others have experience similar issues and the common faults are well documented on here.