A forum for owners of Yamaha TTR250 trail and enduro bikes!

That should make an interesting hybrid! Bring on the photos...

Yes photos please

Interested if you get the wr400 tank to fit.

Ok so the wr 400 plastics and tank arrived. I thought I would buy a rear subframe and airbox too..
Stupidly I now wish I had bought the bits for a 2003 onwards bike simply because they added batteries from then so the airbox could have actually been usable too. Maybe.
Anyway. I stripped the orig plastics and sat on the wr parts..tank sits a little high but not too bad. I was tempted to use the mount brackets from the the wr subframe. But with some tweaking I started setting up a hybrid wr/ttr subframe.
Untill I found that the nearside seat tube was cracked and corroded a bit more that I would have liked for a strong repair..
When I cut it off I found it completely filled with mud. No doubt from the deep River crossings it has had in the past.. lol.
So I basically used the whole top of the wr subframe and most of the lower tubes matched to the ttr ones.
I need to lathe up a mounting slieve for the new seat tubes yet and make the off side lower tube removable then it will unbolt and I can unbolt it to fully seam weld up.
The STD airbox will work fine I just need to weld on some mounts.
The airbox from the ttr is a little wider so I may cut it down a bit so the side panels sit flatter and I can use the wr airbox side panels that tie in nicely with the side plastics.
Anyway. It seams to be getting there..
Daring Raid? Pointless modification or franken-ttr you decide.

Good work Si, glad you are handy with a welder

Steve

Thankyou guys..
To be honest I rarely leave anything STD lol.
I'm wanting some footpegs next and was concidering aluminium but I'm not sure how these will hold up to trail riding.
Aluminium would save some weight but I would rather fit steel ones if it's more reliable.
Also on cards is a lithium battery. And a Koso 32mm carb then I will be playing with porting on a spare head.
I've also rid my motad of rattles. I will post up a how to on this later as I know many have a rattly motad. I kept it because I don't want an anoying noisy pipe for trail riding.
Si

Carb now rebuilt and sonic cleaned.

Main jet set at 150 with 50 idle jet. As a starting point.

New fork seals steering bearings linkage and swingarm bearings all ordered ready for the frame to arrive back from powder coaters.

Upon stripping the forks and yokes from the OE bike I realised the steering shaft is alloy on the OE bike as opposed to steel on the raid.. so I will use that.

Any advise of fork oil weight and oil hight for the OE forks?? I'm 14.5 stone

Si

-- Edited by Black8driver on Thursday 10th of May 2018 06:56:29 AM

Cheers Steve parts arrived today..

I'm a complete skinflint and did loads of searching for parts at cheeper prices and glad to say you were the best plus awesome quick post thankyou.

Si

Frame subframe and side stand back from powder coaters..

Shiney...

Si

Forks rebuilt new bushes and seals. Neoprene covers.

New steering head bearings. Swingarm off OE cleaned with new bearings and seals.

Shock cleaved up and ready to fit. New linkage bearings to fit too..

What started as a cheap build a good one out of 2 crappy ones is snowballing...

Also chuffed with my new pegs.. 13 quid eBay Chinese stainless jobs for a yz. Bit of a ball ache to drill to 10mm they seam to be made of tungsten or something😂 but fit nice.. and look great. Nice wide platforms too..

Si

Coming together nicely. ;)

I was worried about the frame number being covered so asked them to mask it out so I could clearcoat it but they forgot. It's faint but still readable thankfully.

Si

All covered here http://ttr250.activeboard.com/t63813609/powder-coating-information-preparing-frame-powder-coating-v-/  

Particularly http://ttr250.activeboard.com/t63813609/powder-coating-information-preparing-frame-powder-coating-v-/?a=18&commentID=58406502&commentPage=0

Shock and rear wheel on side stand fitted so now it's rolling again feels like I'm getting somewhere. Had hardly any time to work on it so it's maybe an hour every week.. need to pull the engine from the other frame to clean up and paint before fitting..

Can't wait to ride it...

Si

Looking good!

Not a huge update.. I've been stripping my spare bike for parts. One thing I needed from the spare bike was the nicely running and complete engine.

It had an exhaust stud snapped off an oil leak and was really dirty but it ran really well so was just going to clean it and fit it..

Yeah right...

Broken exhaust stud removed blocked up all openings then a damn good jet washing cleaned it up ok 

Unfortunately it also reviewed the reason for the oil leak.. base gasket. It was smothered in clear silicone bathroom sealant almost entirely around the whole barrel..

So I need to open it up then..

I did and it reviewed more horrors.

Piston has partially heat siezed in the past scoring the piston skirt. To be honest it's all below rings and with some wet and dry and a quick home of the bore it would run again.. it's a posh wossner jobby too .

On removal of said piston I discover the small end bore in the rod pretty scratched up the gudgeon pin is unmarked and would prob be fine but there's a little too much play for my liking.. plus it's just not right..

Luckily I have almost 2 engines in bits so I go through to see what I have.. a good bore. A better wossner piston (some shirt scratching but nothing much at all.

2 decent cranks. Plus I needed to fit another camchain guide because this one has the tensioner wearing into it..

Anyway.. whilst contemplating big bore kits prices etc I decided I might as well strip the perfectly working head to have a play with the ports..

Be rude not to at this stage..

Inlet is a nice shape really but exhaust is a bit restrictive with some nasty tightening in areas and some sharp corners on the short turn radii 

Nothing some carbide cutters and sNdoapper rolls can't sort.. so I went to work.

Some light finishing done after photos today and I'm pretty happy.

Need to work the inlet next.. not much to be done there. Some nasty valveseat to bowl steps. Some light reshaping of the short turn radius and just casting smoothing and a portmatch to inlet stub.

Then clean up valves seat cut. Check the spring seat nights and pop together..

I did try to find specs of cams in case there was a intake to exhaust cam swap advantage but no.. they are same part number so no.I am tempted to pop some spare cams on the the llathe and grind the base circles a bit for extra little lift.. dunno yet . If I get time I might..

That's it for now. Hopefully get some engine stripping and cleaning time Friday. Try to put together my best bits..

Si

 

Thankyou Brian. I build a lot of engines from STD to race. And I've ported a number of years but I'm certainly no race tuner. I've made mistakes in head porting in the past but generally can make a decent improvement.
Luckily this head is really good.
I have another with very light pickup on the cam journals but would clean up no problems. And another one that's heavily scored..would need line boring to be any good so I guess that's a week point on these engines. Oil flow to the top end I guess. Mind you all the pistons I've seen are scoffed all on inlet side on stuff indicative of lubrication breakdown prob due to heat. Maybe some extra tolerance on the bore might help. All g with a decent quality oil..
Actually it quite a sterrfull environment for such little amount of oil really. Some extra capacity and cooling I think would work wonders.
I will be fitting an oil cooler for that very perpose..
Si

Got the head rebuilt now valves cleaned up seats recut. Shimmed to spec. And ready to fit.
Slightly scuffed piston cleaned up fine. Bore regained. Giving just over 4though piston to bore clearence. Over spec but it's a forged piston and given that wossner pistons seam to be happier with a larger clearence than they specify and it's an air cooled engine. I'm happy.
Next is to check static compression ratio and squish and I'm hoping to get it running Friday if I get enough time..

Also clutch h fitter cam chain slipper and side casing. Longer bolt fitted to reroute oil for cooler fitment too..

 

-- Edited by Black8driver on Wednesday 15th of August 2018 07:47:12 AM

Hi robs.
Glad your enjoying it. Hard to tell if I'm boring people with my little posts of " I've just bolted this on..." Or not lol
Anyway I've set my mind on getting it running Friday. Not sure how possible it is yet as I only seam to have an hour or so every night after work to get anything done although Friday I might have some more time..
Tonight I fitted the piston and bore. Head cams and timed it up.
Turns over and has compression now..
Need to get electrics on carb fitted exhaust on starter fitted and see what room I have for oil cooler..
Some more pics....

Had a whole day on the bike today.. I decided before I started I would ignoring my whim of wanting it running today as I didn't want to bodge anything or skip things just to have to redo anything later..
Good progress however it was all slow fiddly stuff so took time. Cleaning every part of the loom washing out connections and pasting dielectric grease in all joints. Routing it all (should've taken more pics before dismantling)
But a lot actually achieved.. in fact the list to do is...
Fit silencer. Carb. Plastics and tank. Make mounts and fit front light. Fit handlebar switches and levers. Clutch cable. Throttle cables. Fit oil cooler. Fill and prime oil. . Fit gear lever. Fit frame gaurds. And sump gaurds. And run it..
Prob other things but it really is taking shape now.. starting to get excited now..

So it looks like a bitter sweet time for me right now.
I've got the loom on carb fitted. Just linked the cooler pipes right now to start it.. turned it over got oil bleed. Checked for spark. All good..
And it runs yeahy..😁.
But........
I'm not happy with it. Firstly the starter sprag is kaput.
My own fault. I didn't fit the known good one as it was still on the other motor and I didn't strip it fully. Now I read that the rear spindle makes a makeshift puller. So need to swap that over..
But it runs and revs good. But my old scuffed piston that I lightly sanded is fine but I had to hone the bore a bit more than I'd would have liked. At 5thou clearence I should have know but thought it was worth trying. But alas there is piston slap and although it may run for quite a while like that I think it's best for a rebore and new piston. Going for 74.5 or 75mm with 2.5 to 3 though clearence.
Also going to fit a new genuine cam chain as it's another thing on my mind..
Also found that with the wr/ttr hybrid subframe the bend in the motad is a bit too close to the mudguard plastics. So I've ordered a wr450 silencer to mod. A shame really because the motad sounds sweet and pretty quiet.
So I've had to put some bits up for sale to pay for new bits..
Cheap bike has become let cheap but I wouldn't be satisfied unless it's right..
Also my main jet needs to be smaller.
That's kinda good news as it means even though my carb is bored out giving less depression meaning that it would need bigger jets. It appears that the ported head is flowing plenty more.
So sell some bits and fit some new bits..

Si

Good work and well done with it so far

Man that looks great, congrats!

If I saw that on the street I would be horribly confused

The carb I did think about putting it on the mill.. or lathe but in the end I just ported it as I would a head.. with carbide burrs and sandpaper rolls. I kept a sort of progressive egg shape but it's more oval than it was originally.. I haven't worked out it's new overall cross sectional area but its a fair amount more. With I guess at least 1mm taken out of the sides and maybe 2 or more in other areas.
First impressions is it works well on the short 3 or so runs I've done on the private road. But taking it slow as I need to fit the brakes...
Si

Still a few finishing jobs to do.. but ready to use.. mot on saterday