TDR250 newbie

[TDRNL]

Hi all

I am very happy as I have just acquired a project bike TDR250 from 1990. I have experience in aircooled RD's but this is new to me. I couldn't find a decent TDR forum to find information/ask questions so I hope this is the right place for me.

The bike requires quite some work on it (electrics dont work, engine runs but not properly, etc). Before I start I just want to understand a basic question: Does my TDR have the 2MA engine, or a different one? If it's different, wich engine is it? This is essential for me to understand so I can look up the proper information.

Hope I can find a lot of information here and ask questions when required.

Thanks already!

[anadr0id]

Try here: https://tdr250.co.uk/
Forum activity is low, but there's lots of useful info.

TDR has the 1KT/2MA engine. Slight differences, like 1st gear ratio and the ignition system (shared with R1-Z).

[TDRNL]

I have tried to sign up but for months but get no activation of my account unfortunately. Also no response on the admin email for months..

Thanks for the info already!

Another question which is quite urgent: The vacuum petcock doesnt shut off and as the right carb is overflowing, it wont stop leaking. Are these petcock's rebuildable?

[anadr0id]

The mods/admins seem to be quite absent. It took me months to get registered. Keep trying.

An overflowing carb indicates a leaky float valve. That needs to be fixed first. A healthy carb shouldn't overflow even when the petcock has been left in the PRI (prime) position overnight. I've ordered lots of parts from Yambits: https://yambits.co.uk/
Perhaps not OE quality, but most parts have been acceptable.

Float valve: https://yambits.co.uk/tdr250-carb-float-valve-p-28721.html
Fuel tap repair kit: https://yambits.co.uk/tdr250-fuel-tap-repair-kit-p-29530.html

[Rasher]

NRP do good quality carb parts, typically original carb manufaturer stuff or same spec so I got my float valves from them for my TZR which also liked to piss fuel.

As for the fuel tap I used a rebuild kit on mine and it still leaked fuel through, but was pretty manky looking (lots of furry crap inside) so in the end I bit the bullet and bought a new one.....

...After all that went to a bike night last night and when I started it to leave it started pissing fuel out of one of the overflow pipes, but by the time I got home it seemed fine - these old bikes are bloody great!

[TDRNL]

Just removed and inspected the carbs. Not sure who worked on this bike but at least I found out why the bike wasnt running right.

Score:

2 bent needles
1 carb had the main jet chilling around at the bottom of the bowl

Have bought 2 rebuild kits, will mount and set everything to spec.

[TDRNL]

PS: I see there are 220 main jets installed, shouldnt these be 210's? Or is there a 220 version as well? Spark plugs looked quite decent (dark brown).

[Need2Speed]

My TDR 250... for your reference...

[anadr0id]

PS: I see there are 220 main jets installed, shouldnt these be 210's? Or is there a 220 version as well? Spark plugs looked quite decent (dark brown).

210 from the factory. Workshop manual: https://tdr250.co.uk/downloads/TDR250ManualEN.pdf

[Rasher]

Don't foget anyhting may of happened to this bike, my TZR has been a world of discovery;

I knew it has a 1KT engine in a UK chassis, but then found loads of stuff, bodywork of at least 2 bikes, top fairing is re-sprayed from red to blue, rest is original Yamaha blue, different key for ignition and tank / seat. Carbs had different float needles (with one leaking causing flooding). Flywheel Lightened - and likely to break up, so had to find standard one.

THe engine was allgedly rebuilt by a former owner and bike mechanic, but a camera down the bores revealed powervalves not perfectly lined up and it looks like someone has been at them with a grinder (but pistons / bore mint) coupled with the lightened flywheel maybe the engine (or parts of it) from a race bike, or maybe just a horrible home tuning job (inlets untouched)

On the dyno the fuelling is quite different from one side to the other (with same jets) further suggesting something weird going on, and I had an Ignitech programmable ignition / PV controller fitted and when adjusting that ont he dyno weird things were going on - almost as if it may have one tuned and one stock barrel - or just some shit home tuning going on....

....As it is running quite well all that can wait until Autumn when I will have the barrels off for a good look and see what the score is, it makes a healthy 47BHP with a good spread of power (on MJ77 955 spec pipes) and feels nice on the road.

If the rear caliper is stuffed then currently you can get chinese copies for £30 on ebay, assuming its the same as the TZR.

[Need2Speed]

Don't foget anyhting may of happened to this bike

amen to that - standard was the day it left the factory...

[TDRNL]

Definately true

Pistons do look like they are not too old and the hone pattern is still visible on the walls. Does someone know what brand piston this is?

[Need2Speed]

detonation marks - rebuild the engine -

[TDRNL]

More pictures. My first reaction was also detonation. However, upon further inspection it looks like the top of these pistons is not super flat by design and the LED lighting exaggerates it a bit.

[TDRNL]

Looks like the pattern on this piston:

https://www.cmsnl.com/nl-nl/products/piston-1st-os_3601163503/?gad_source=1&gad_campaignid=20699376143&gbraid=0AAAAAD_htrOz_5uQdyWygRVIcTL_SVu2a&gclid=CjwKCAjwx8nCBhAwEiwA_z__02VpKKEnNNE5yP_NOYSenS94U7DDWEvcQylreQYd9OqfSBdeDz73zRoCxjYQAvD_BwE