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Discussion Starter #1
I've been lurking the net and UK forum searching for Yamaha TDR 250 information and inspiration...
I have a little Kawasaki KMX 200 (Single cylinder 2 stroke with 30 bhp) I've been using to pop down to the stores with but poor Kermit doesn't have that much get up & go!

So I've been hankering after a Supermoto style bike for years & always find myself looking at Honda CRM 250's & 2-stroke KTM's, even big single thimper Hussabergs, but their 20 hour engine life (Before needing a refresh) and uncomfortable seats put me off (Despite the riot I hear they are to ride)!

Then I remembered the TDR250! - 50bhp 2 stroke twin - often described by owners as the most fun bike they'd had in the past.
So I started looking around and they're not that sought after here.... & have good potential for modification.
By doing some google searches over the last couple of days I realised they're still well rated as fun bikes.
So I searched online and found one in good shape with only 11,300km for a decent price. I bought it!
I'd already pre-promised my wife I'd sell the KMX200 (Which I'm bored with, really) to help fund the change to the TDR.
The new bike should be here sometime next week, I expect...





Not too keen on the red metallic non original (Lexus?) colour, but apparently it's been professionally sprayed on. It does look fairly tidy & runs well so the seller says. Mostly I wanted a rust free bike with low mileage which it is - aside from the rusty spokes which won't be on the bike for much longer anyways.
All of my machines get modified so before taking the plunge I did a little research on alternative swing arms, upside down front end, Excel (Or other) 17'' Motard rims, complete exhausts with larger expansion chambers, re-jetting, reeds, better brakes, suspension (Probably a Maxton shock & fork re-work) hidden indicators, carbon bits, etc.
I like top quality things for the job so I don't have to make changes twice or more - don't care if it costs more than the bike's worth - this one should be another keeper, I reckon...

It might become something a bit like this one, I found as an example:




Won't be a project I do very quickly as I have my family & home to share my spare time with, but looking forward to 1st riding it and 2nd taking it apart and making it a lot better :).

The SP2 is being used less and less these days, but it'll never leave my stable. I just need something smaller to get around with locally. I feel the RC's too special to be a runabout!
 

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That black/yellow bike is badass. Just lifting the front fender and getting inverted forks makes a big difference. Love the acerbis bark-busters!
Are 2 stroke bikes street legal in Japan? I thought they had strict emissions controls.

That should be a pretty cool project. That bike has great potential- but first thing first; you gotta get rid of that blk/wht graphic stripe. ;)
 

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Discussion Starter #3 (Edited)
I expect to make it better than the black one, in the end...
I might even just repaint it black (Or a dark grey perhaps), or another colour to begin with, but the stripes are going anyways. It's still 300km away and I haven't laid eyes on it yet - I bought it on the three pictures and description from an auction (Japanese tend to be very honest and this guy has excellent feedback, so I'm not worried...).

Yep, 2 strokes are perfectly legal in Japan. I wanted a 250 specifically, as it doesn't require any inspection ever...only renewal of compulsory insurance every 2 years (Which is cheap as chips for a 250). Not like over 250 which requires ball busting hurdle jumping... The SP2 will require another Shaken in 6 months. :(

No shaken on the 250 means it can get as modified as I want. So it's going to get a lot of stuff done over time... :D
 

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Sweet stuff Stig, look forward to seeing this one take shape!!!
My next bike is a super moto as alot of the local guys here do track them as we have a super moto track here.
 

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Great, now I will have something to ride if I ever make it back to Japan.:D

Great find....now get to work and post lots of pictures:cool:
 

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Looks like a gooder Stig. Does Japan still have that wicked hard testing and licensing requirements like they did 25 years ago? I remembe Denis Rouse (Rider Mag's former editor) went over and did the training and took his test. Passed, but just barely, was a real eye opener of a read.
 

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Discussion Starter #9
Whilst waiting (About 10 days more!) for this toy to arrive, I've been doing some more reading up on it. Apparently it was only imported to Canada, but not the US. Shame, they're great bikes - ahead of their time being the original Supermoto before anyone had thought of them.

Here's a few clips.

0-100 mph (33,000km bike - wonder if the engine's still the original?): http://youtu.be/1zvvNh0SUSo

Yamaha's original promo video: http://youtu.be/s6-fThTFJec

Most have long since been neglected then forgotten. Apparently it's also possible to fit a tuned 500cc Yamaha Bashee engine to these, or 2 x DT200cc cylinders with a different crank for increased stroke. Not sure I'll do anything like that, but it would surely be interesting (If not lethal)!

Licence? - It's a tier system:. Up to 125cc on a car licence, 250-2 stoke or 400cc, then for full licence for big bikes there's another test. I never took it - swapped my UK licence for a Japanese one but I hear it's a pain in the @ss.
Was riding the KMX yesterday afternoon along country lanes behind our home, opening it up - and imagining what the TDR will be like with nearly double the power and much the same weight. Fun for sure, but I don't trust 21 year old suspension technology and weird 18 inch front wheel that it's difficult to get tyres for. Super sticky 17 inch Supermoto tires on wider rims and proper suspension for starters, before I explore just how far it will lean over. It's going to be a giggle bike.

Can you tell I'm a little excited about this ring ding? :D
 

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Excellent choice my friend. It is not considered that light weighted bike really. It's nearly 350 pounds with all it's fluids. But the TZR 250 engine is awesome. Lots of power and torque.
If you turn it to a supermoto bike, I believe you will need to short gear it a bit cause in low rpm isn't that powerful and with the street tires sticking good on the asphalt that effect is amplified. You'll find out that a -1 tooth on the front sprocket makes it a lot more of fun on the street. But if you go for the 2xDT200 cylinders or an RD350 engine then it won't be necessary otherwise you will keep wheeling it on 3rd gear at 50 mph without clutch poping :eek:
This was a very popular bike around here during the 90's and at some areas still is.
It can literally go anywhere.
 

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Discussion Starter #11
Hi Makis,

Sounds like you know these! I thought it was 135kg? - Maybe that's dry though...
160kg sounds pretty heavy, but then my VFR 750 tipped the scales at 230 something kilos the other day when getting it legalised as a fresh (re-)import and it doesn't feel cumbersome at all. I don't plan to do a lot of off-roading with this, if at all. Just want a nimble & quick town bike which it is...

-1 tooth less at the front sounds like fun, or maybe a large rear sprocket by three teeth?
I don't think I'll do the DT200 mod. RD350 is a pain to do, I hear - not so simple?
The bashee engine change sounds totally bonkers. Some 85 bhp or so is possible. Yikes!
Anyways, I'll probably keep it standard engine wise and just bolt on a better exhaust & re-jet it to suit. It's only a town bike but I do like the idea of the wheel coming up easily on the throttle. I think these do hoist the front without too much difficulty, not that I want to monowheel a lot. Only a little. :p

It will definitely be a Supermoto. That was the plan from the beginning. I'm trying to buy some WR250 upside down front forks right now, ready to begin some changes. ;)

Maybe you can give me some advice on tuning it down the line. A bit more power, not less reliability (So I probably won't port it! :D).
I don't have much experience with 2 strokes, that which I did was about 30 years ago and they weren't good. Lots of seizures from tuned 2 strokes, so I gave up and went with Honda 4 strokes and didn't look back...

Till now. :D
 

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What ever you do, keep the the stock air box. If you need an after market air filter (due to am exhaust replacement) use one that replaces the stock one within the stock airbox (like Daytona's air filter sheet).
Give plenty of gasoline in your mixture and never exceed the 2% ration on mixture oil.

I spoke about it's weight on driving experience. So to be exact it's 139kg dry/150kg wet weighted.

http://www.motorcyclespecs.co.za/model/yamaha/yamaha_tdr250 87.htm

Start the project and let me know if I can help step by step cause the last time I overhauled a TDR's engine was back on 2002 and I need a lot of pictures to catch up.

A -1 tooth front sprocket is ALWAYS the best solution on YAMAHAs......cheaper and easier to replace.
Swapping the front suspension is a great idea but it would be better if you could install one from a WR450F ot YZ450F cause the WR's is really old tech and won't see much difference in the corners.
 

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Discussion Starter #13
Thanks Makis, that's so cool of you to help like this. Really appreciate your advice.
This engine doesn't need any overhauling (I expect! - as I haven't even heard it run yet :D), but I'm already feeling pangs of temptation to buy one that's for sale cheap (http://page12.auctions.yahoo.co.jp/jp/auction/p224940938), send it to you and have it transformed into a fire breathing 400 then shipped back to Japan...but the costs of shipping would probably kill that idea!
I'd best see what the power's like and what it behaves like first. I don't think I need it to be that wild... !

Cool on the sprocket, I just figured it would last longer by adding some teeth to the rear than taking one away at the front perhaps?

I hear you on suspension. The WR250 front forks went for stupid money, roughly 300 Euros, so I let them go (Auction). One thing that puts me off too, is the positioning of the disc and what looks like a smaller diameter front one, compared to original. That wouldn't be an upgrade, as say an R1 caliper fits directly to the original forks and it has a larger diameter (Semi-floating?) front disc.
Trouble is - WR450F or YZ450F front forks are rare in Japan, if ever available.
So I'm bidding on these right now (http://page.auctions.yahoo.co.jp/jp/auction/161206374 Highest bidder...) But with 5 days to go, I know with this much interest they'll be expensive and this is always going to be the case with clean forks that are upside down for this category of bike!
Wish I could put some white power Upside down front end on from say a KTM... but stuff like that isn't readily available and is untried AFIK.
Whatever I buy would be re-valved & modified by Maxton in the end combined with making a new rear shock anyways - which will make quite a difference, if my VFR750's forks are anything to go by...

Lots of ideas, but no firm plan yet. That's part of the fun of searching to see what's possible, so just thinking out loud for now. Not in any rush, as I know what will happen if I do - parts will sit there waiting to be fitted, as there's always other stuff I need to get done first on other things in life. So one bit at a time, I guess. Start at the front and work my way through each bit perhaps. ;)
 

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Thanks Makis, that's so cool of you to help like this. Really appreciate your advice.
This engine doesn't need any overhauling (I expect! - as I haven't even heard it run yet :D), but I'm already feeling pangs of temptation to buy one that's for sale cheap (http://page12.auctions.yahoo.co.jp/jp/auction/p224940938), send it to you and have it transformed into a fire breathing 400 then shipped back to Japan...but the costs of shipping would probably kill that idea!
I'd best see what the power's like and what it behaves like first. I don't think I need it to be that wild... !

Cool on the sprocket, I just figured it would last longer by adding some teeth to the rear than taking one away at the front perhaps?

I hear you on suspension. The WR250 front forks went for stupid money, roughly 300 Euros, so I let them go (Auction). One thing that puts me off too, is the positioning of the disc and what looks like a smaller diameter front one, compared to original. That wouldn't be an upgrade, as say an R1 caliper fits directly to the original forks and it has a larger diameter (Semi-floating?) front disc.
Trouble is - WR450F or YZ450F front forks are rare in Japan, if ever available.
So I'm bidding on these right now (http://page.auctions.yahoo.co.jp/jp/auction/161206374 Highest bidder...) But with 5 days to go, I know with this much interest they'll be expensive and this is always going to be the case with clean forks that are upside down for this category of bike!
Wish I could put some white power Upside down front end on from say a KTM... but stuff like that isn't readily available and is untried AFIK.
Whatever I buy would be re-valved & modified by Maxton in the end combined with making a new rear shock anyways - which will make quite a difference, if my VFR750's forks are anything to go by...

Lots of ideas, but no firm plan yet. That's part of the fun of searching to see what's possible, so just thinking out loud for now. Not in any rush, as I know what will happen if I do - parts will sit there waiting to be fitted, as there's always other stuff I need to get done first on other things in life. So one bit at a time, I guess. Start at the front and work my way through each bit perhaps. ;)
The front you're bidding on is a very very good choice.

Just bear in mind that it is set up for a 50kg lighter bike. So you'll need a 7,5W Ohlins oil and a pair of springs to make it work on the TDR.

Also I believe that you'll need a triple tree set swap to make it fit. Remember that the TDR has a normal telescopic front so the up side down one needs larger holes on the yokes to fit in. If I were you, I would also buy a set of triple tree from the CR250F as well and swap the TDR's spindle (the axle that goes in the steering stem bearings) and have it pressed and welded on the CR's lower triple. Very common mod in Greece when swapping front suspensions.
CR250F front wheel's axle is necessary as well and all you need to do is to swap the TDR front wheel's bearings to fit it in (using bearings with TDR wheel hub's O.D. and CR wheel axle's I.D. ;) )

About the engine, I overbored an RD350LC back in 2003. Full WISECO pistons kit, porting, balancing etc. It reached 422cc and of course my biggest problem to make it work was the fuel supply efficiency.
After a lot of experiments I ended up using a pair of 39mm Keihin FCRs with fuel injection system on sudden throttle twist and a CBR600F4's fuel pump because beyond the 5500rpm point the gravity wasn't enough to supply gas in the carbs.
Like the TDR, the RD is not equipped with a fuel pump from the factory.
But you need to construct the whole wiring circuit with the fuel pump relay to make the fuel pump work properly.
TDR's rear suspension is quite good actually. All you need to do is to have it serviced using modern suspension oil (I would go for an Ohlins 5W), re-spring it to your weight and refill the nitrogen tank.
Then you find a rear swing arm from a TZR 250 3XV (the V2 engine one) and, oh man you'll see what cornering means.
I have fitted an RVF400 NC35' swingarm once on a TDR 250 (single side arm) back in 2004. It looked awesome, worked very well in cornering but it was a bit short and the bike was wheeling on 4rth before you even touch the throttle after up-shifting :D
In addition you'll have to take good care of it's electricals. YAMAHA had a lot of electrical issues back then. Use a separate 3 wire (2mm each) cable from the stator to the reg/rec for better supply to avoid over-temperature effects and sand paper any ground contacts.

If you don't have it already, here is the service manual

http://tdr250.co.uk/downloads/TDR250ManualEN.pdf

Keep us posted my dear friend :)
 

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Discussion Starter #15
Hi Makis,

Thanks again, buddy. Funny that I'm getting the best advice from an individual on the RC51 forum, but hey!
I've still to research more, but the Honda CRM250AR model has similar upside down forks, so perhaps I can use the triple trees from that assuming they're the same diameter.
It's a commonly available bike in Japan and so are forks (relatively), although unfortunately the aluminium anodised tubes tend to corrode and I don't fancy fitting manky parts onto this project.
The CRF250's look mint, so they're a double good choice. They'd be put on as is first, but once I have the front suspension, wheels & brakes sorted out then I'd send the forks to Maxton & have them build me a shock. I'm that keen on their products I see no point to experiment or go it alone with spring rates, etc.besides which I think their products aren't too badly priced.
I've yet to do more research but it's possible the CRM brakes and spindle are the same, or the brake calipers at least have the same mountings & I have found some different caliper carriers for the CRM forks, as well as 320mm disc, so it's getting there. Speedo may become redundant, but then I'd fit a digital one.
I am also bidding on a TZR250R 3LN swing arm complete with spindle, adjusters and brake caliper. Don't like the 3 rivet nuts on each side, but I could live with those (I'm current highest bidder for this too: http://page16.auctions.yahoo.co.jp/jp/auction/u43797292
I did think of an NC30 rear end, but I think motard bikes should really have Excel wide rims and stainless spokes, as opposed to cast wheels. They're just more sexy that way to me :)

I really shouldn't be shopping for bits before I've seen or ridden the TDR but I know I'll like it and these bits aren't necessarily easy to come by so I'll snap them up while I can unless they go to truly silly amounts!

As for engine, another idea could be to send a spare engine to Stan Stephens in the UK who is a 2 stroke tuning legend. Make the DT400 kit and tune it mildly, whilst detailing the entire engine. Bit of a pipe dream, as the cost would be prohibitive for transport, but that's no hurry really.

Still need to think of a colour, but so far Yamaha R1 blue metallic with original decals would seem a bit more modern and is the design that's winning over my mind. But I'd also like to modify a front cowl to fit some better lighting, to help modernise it. Trouble is, that's a LOT of messy work for not a lot of return, so maybe I'll just live with the headlight.

Don't know if the ignition switch would fit with another triple tree, most likely not - but not bothered about that one way or another. Theft isn't a big problem here, although I'd be very careful with a toy like this, as it'll be desirable to youngsters here. I'd just carry a big lock. Get myself an original rear carrier to bungee a decent ABUS or other lock to.

Lots of ideas running through my head, but eventually by default things will begin to take shape from the parts that appear & would work together. It's for sure it'll cost me a lot more to do it up than what it cost to buy, but I'll spread the costs over time.

No rush to finish, but looking forward to the other rush...
2-stroke TDR rush. :D
 

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Discussion Starter #17
Hi Makis,

Thanks for your help. :)
I looked at the various TZR250 swing arms that would fit, but for the TDR I think I prefer a straight aluminium one with no bracing, etc. After all, the bigger Motard bikes from KTM, Hussaberg, etc. don't use them, so I figure to make the TDR most modernised a plain aluminium one will work well aesthetically. I've seen some pics of examples with them fitted and they look a bit out of place to me.
Besides being easier to clean, the plain 3LN arm will allow the shiny spokes & alloy rim to be seen. :D
The other thing is, the 3LN arm that's available now comes with the adjusters, rear caliper brackets, etc. so aside from different length bones, it's ready to use - which is nice. Saves time!
Not sure what the 3 rivet nuts are for on each side. Hugger?
Anyways, there are other 3LN arms that don't have the rivet nuts - with "Deltabox" written on the side. Cheap to buy and easy enough to fit, perhaps.

Appreciate the pics though. buddy! :)
 

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Discussion Starter #20
Yep, CR500 in a CRF frame. I also really like the SXV 550 but they're expensive here and hard to justify as a local tool in these times. I also hear they're a bit fragile in the engine dept!
Would also mean another shaken, which is a PITA every time. 2 bikes and three cars is enough. I hate going to places they stick sniffers up a machine's rear end.

Swinger.... Jeez, must be xmas for them whenever anybody buys one. :)
 
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