TDR 125 19XX

Mightyman · 4 May 2017, 16:43

Took the cylinder off today. Found a piston with a smashed skirt!

Cylinder walls don't look scored, but it could do with a rebore.

The rings and small end bearing look in VERY good condition so I'm thinking at this point the previous owner may have put in a cheap eBay piston that perhaps wasn't the right size and caused piston slap?

No up and down play on the conrod either so I'm sure that'll be good to use again without needing work done to it but I'll have to split the cases anyway just to grab any bits of piston lurking down there as I can still hear a small scratching sound when turning the engine.

An overtightened kick start nut stopped me from progressing but I'll get that sorted tomorrow.

Does this look like an aftermarket inlet as it doesn't have the hole for the oil pipe on top?

Mightyman · 4 May 2017, 16:43

Managed to get the kick starter lever nut off after I got the grinder out.

Took the clutch cover off to find a bad sight.

Although on the plus side, the clutch plates, springs and spring retaining bolts look brand new!

Couldn't quite work out what the broken bits were, then these black rubber bits starting appearing from no where!

Figured out where all the bits came from once I took the clutch off...

That was what the scratching sound was. Couldn't work out how something like that could have happened, the only thing missing was the washer that goes on the end of the rev gear but that wouldn't have cause this amount of damage. Then I noticed this.

I removed the gear to find that the circlip behind it had been pushed a little bit too far back. This could have caused the kick start idling gear to wiggle just enough that it hit the back of the clutch basket. Not 100% sure but seems feasible.

Also there is a hole here, but I'm not sure if it is supposed to be there.

All organised for another day.

tdrpaul · wrote on 13 Jun 2016, 22:55

Re: TDR 125 19XX
Hi there I was going to buy this but the guy took it off eBay.
I have the same bike that I'm tidying at the moment.
The standard carb is a dellorto phbh 28.
My one was imported in 2002 and registered to the guy I bought it from, the bike has been off the road in the owners shed since 2002 so the piston was seized in the bore and the carb was full of the usual green residue, nothing a new piston and a wash in my sonic bath didn't cure.
It is a bit different to the dt like shorter rear shock, radiator ect and not being restricted is alsayw a plus.

Good luck

Paul

Mightyman · 16 Jun 2016, 13:45

Hi Paul, I did get lucky with the ad I must admit. The chap had it up for £245 on an auction and no one placed a bid! I missed it at the last minute and so messaged him offering £200 to collect and to my surprise he said yes! That's interesting that you have a 28 carb as the inlet on my engine measures around 35mm. Maybe I need to purchase another inlet if mine isn't stock.

tdrpaul · wrote on 16 Jun 2016, 13:45

@MIGHTYMAN my inlet was damaged so I thought that's ok I'll fit a dt one, the dt manifold was to small for the dellorto carb so I enlarged derestricted and flowed it with the help of my trusty pen knife and a Dremel with a flap wheel on it.

Mightyman · 16 Jun 2016, 21:10

I'm definitely considering just getting a stock DT carb and inlet as a Dell Orto is proving too hard / pricey to source.

tdrpaul · 16 Jun 2016, 23:18

@MIGHTYMAN I found a dellorto phbh 28 for about £60 new, they use them a lot on vespas. I was thinking about using one on my 180 gilera runner fxr but I'm trying to keep it standard.
https://www.wasp-performance.co.uk/onlineshop/prod_1875543-Carburettor-PHBH-28-BS-with-Manual-Flip-Choke-Lever.html

I think I still have the standard jet sizes written down if you need them.

Calum · 17 Jun 2016, 11:42

@tdrpaul The stock carb is better than those PHBH Carbs. They are a 28mm round slide carb. Flat slide is far superior.

tdrpaul · C Calum 16 Jun 2016, 23:18

@Calum hi Calum I agree the flat slide is a lot better carb but the dellorto phbh 28 is the standard carb for the early Italian made tdr 125.
I have a low mileage one owner 1989 tdr and I want to keep it totally original but finding original parts isn't easy.

Paul

Calum · 17 Jun 2016, 14:36

@MIGHTYMAN or grab a mikuni tmx 32. They are common enough.

Mightyman · 17 Jun 2016, 17:52

@Calum Would I then still need a stock DT inlet for a tmx 32? Or is there a chance my current BIG inlet would be alright?

tdrpaul · wrote on 17 Jun 2016, 17:52

@MIGHTYMAN the manifold in the pic is the standard manifold for the dellorto carb which has the oil pipe connection on the carb.

Calum · wrote on 17 Jun 2016, 18:00

@MIGHTYMAN Stock carb is 28mm TMX 32 is 32MM. So it should fit,.

Mightyman · 4 May 2017, 16:44

Now it's (hopefully) going to be warming up outside a bit, I thought I would get back into this project again. Last night took a look at the crankshaft to find some of the bits of piston had been lodged inside the gaps in the conrod..

https://youtu.be/oJv-wv8eEYQ

Also started the clean up job on the engine cases.

A bag full of steel wire rotary bits

Starting it off

https://youtu.be/9bUSrAkcnSs

15 mins = 1 down!

Calum · wrote on 28 Jan 2017, 15:40

Looks like that crank is going to want a rebuild.

I don't know how easy it is to get ahold of a new crank pin for these engines. If that crank pin is scored then you may find yourself needing to buy a new crank.

Mightyman · wrote on 28 Jan 2017, 16:14

The crank pink should have been sheilded by the bearing I would have thought? I wasn't going to rebuild the bottom end as it all turned over very smoothly but luckily I decided to pull it all apart in the end!

Calum · wrote on 28 Jan 2017, 17:23

What bearing lol. It's a roll cage bearing so it's completely exposed.

If the big end bearing has got bits of piston in it then consider it thrashed.

For the cost of 40 quid. I would rebuild the crank. Otherwise it will fail and cost you an engine.

Mightyman · wrote on 28 Jan 2017, 18:11

Don't worry it was going to all be rebuilt the second I opened the cases!

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TDR 125 19XX