Completed Bike and notes for restorers

Completed bike

Some final adjustments during the day, in particular setting up the carb, as the bike felt lumpy as it pulling away.

After adjusting the float height

Panels in the right place

|Bike 1|Acquired from a garage in Tredegar from Kev, running but needing some attention (ie complete rebuild)|
|Bike 2|Second bike came AP Motorcycles who are serial importers of cars and bikes, and the good thing is they know their dirt bikes. |
| Piston Kit | Got an original 0.50mm (2nd oversize) piston kit from Keith Alderman at Motolink . There are plenty of OEM Yamaha pistons and Wiseco piston kits on eBay in the US, though you need to take into account shipping and the exchange rate. |
| Crank bearings, seals and gaskets | Also from Motolink as well as lots of information on the MX250. |
|Tank Decals| These came via Speed and Sport Yamaha’s ebay shop and were the only place I could find who did them. |
| Plastics |The front and rear mudguard as well as the side panels came from [ Reproduction Decals -> ] in Canada however these came from DC Plastics who indeed sell a a complete plastics set for the 1974 MX . The parts from Repo Decals were cheaper than the set on the DC site (I think?) |
| Front number plate | I got from Yuniparts who are mainly on ebay UK and specialise in XT/TT 500 parts. Luckily the TT parts also fit MX250/360 and SC500’s. |
|Seat Cover | Came from Pit Replica in Thailand, and arrive in 10 days |
|Handlebars and Levers| I already these from an incomplete trials bike project. I used standard Renthal bars and a pair of the excellent Domino levers, which are cheap but are pretty durable. These originally came from BVM in Stroud, but available from anywhere. I also got a set of pattern copies of the original fitment bars, again from Yuniparts as they are like the TT/XT fitment of the day. |
|Throttle and Cable| A nice quick action set from Motolink with the appropriate cable to match |
|Clutch Cable | A pattern copy of the original cable, again from Motolink|
|Brake Cable | After some searching and thoughts about modification, ordered a good value one from Yuniparts (for ¬£7.65) though it was listed for the later MX250B. It fits the earlier MX250’s equally well. Yuniparts also stock pattern brake shoes (front and rear) for the MX250, as they are the same hubs as for the TT500. |
|Spark Plugs| From the ebay seller in Alderney, both standard and Iridium plugs|
|Tyres| From my local offroad supplier in Pontrilas, LG Racing Gone for medium compund set of Michelin Cross AC10 |

Did the numbers last


As well as the parts, I got some of the work done, ie the bits I couldn’t do myself (like the rebore and the rechroming). The rebore was done locally (to a very high standard by Russ Tyler, whilst the forks went to [ A M Philpots -> ] who do an excellent collection and delivery service.

I decided to paint the frame myself, rather than powder coat it and did this with Hammerite Satin paint (from aerosol cans). I was really pleased with results and would do this again with any bike I could get the approx paint colour for.

The wheels were respoked (with galvanised rather than stainless) by Gerard Pettit done in Caerphilly and again excellent service for reasonable money. I’ve heard that Central Wheels are pretty good and they can also potentially polish the hubs etc if you want (I didn’t)

Some more notes of restoration

What’s good about the MX250 and the MX250A is they are pre74 eligible (the MX250B was monoshock) and though never imported to the UK there are loads of bikes and spares in the US (and also AUS and NZ it seems. There are common parts with the Yamaha DT250 and DT400 of the same period (not the later ones), both engine and cycle parts and lots of cycle parts are interchangeable with the Yamaha TT500 (lightweight version of the XT) which are currently massively popular in the UK (and silly money).

Restoring a silver MX250 (1973) or a yellow MX250A (1974) should both be straightforward and plastics and decals are available for both. I must admit the Yamaha US yellow wins for me.

Make sure you get hold of the right MP7 flywheel puller M20 1.5mm RH thread as you’ll need it and won’t get the flywheel off without it. It fits only a few CDI / small flywheel bikes and I had to order one from the US, which turned up in 10 days [[I can now recommend international eBay to anyone after completing this restoration, with parts from the UK, US, New Zealand and Thailand being ordered successfully without hassle ]].

Before my first race, I’m already happy with the project and working on the bike. Its easy to work on, and the engine strip was relatively straightforward (to a four-stroke and a Rotax trials engine) and would make a good first project. Spares are not a problem and you just need to plan up front on what you need and when.

Maybe a MX360 next (have some spares now) but lets wait till the first meeting and see how i get on.

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