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Post Info TOPIC: 350cc Big Bore Kit for the TTR250 - updates and gossip!


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350cc Big Bore Kit for the TTR250 - updates and gossip!
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Any guesses on the likely cost of these. Just a ballpark is at all possible.

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Sorry for not answering yet Rich - v difficult to tell until my machinist has actually done one - it's the last unknown (what D Rumsfeld would call a known unknown!)
It will be more than a 325 kit, but hopefully not too much considering the only machining you need to do is the crankcase opening, as barrel and sleeve will come already done.
Once again, I can only apologize for the time this is taking. More news soon, promise...
Simon



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Thanks Simon.

Having owned the bike for nearly 5 years, im at the itchy feet stage of wanting an upgrade!

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Yeehaw, we're finally getting somewhere. Got 2 shiny 350 barrels back from the machinist today. 2 prototypes on the way to production. I have ordered a pair of pistons from Wossner (the only people who would do small quantities for reasonable money). Unfortunately, another 6-8 weeks of nailbiting anticipation, but I've got to put my crankcases back together first anyhow.

Here are some pictures of the machining:

2017-12-09 10.49.28.jpg

2017-12-11 10.23.37.jpg

2017-12-18 09.22.49.jpg

 

 



-- Edited by mossproof on Friday 22nd of December 2017 08:29:58 PM

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What are the cons of Nicasil instead of a steel liner?

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Mmm, shiny!

 

P1010580.JPG

P1010582.JPG

P1010581.JPG

 

If you look closely you can see the machining of the crank case side. This is the biggest sleeve that will fit in these cases. If you want to go bigger than 350 boys, one of you is going to have to develop a stroker. It ain't me babe. (At least not this year!!!)

 

As far as costs go, the most horrendous bit was the casting pattern. Not putting too fine a point on it, it cost just under a couple of K to get it foundry ready. Casting plus sleeve, custom made piston, and machining costs were all quite evenly priced. With this in mind, and recognizing that we are not going to be selling hundreds of these kits (would be nice, but let's be realistic) I suspect that a final figure is likely to be around, or just below, the £800 area. This is obviously more than the Thumper 325, but all you need to do to the engine is get the crankcases machined out. FYI, I had mine done for £30 by my machinist. Nametab Engineering in Redditch.

When it's all together and run-in there will be several dyno sessions with various exhaust setups, starting with totally standard.

Fingers crossed for the new year...

Ride safe and dream of bigger wheelies,

Simon.

 



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RE Nicasil

Cost, for one, especially small batch. Plus you're stuck with that and no oversize pistons later on. These off the shelf liners are not expensive. It was the cost of castings that bumped this up so much. Alternative was 3D scanning an original barrel and modifying the scan where necessary then machining out of a lump of billet LM25TF alloy, which I'm reliably (maybe) informed would probably cost even more for the low volumes.



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Barrel looks good and if my math is good then a 86mm piston on the 59.6 MM stroke will give you 346cc same size as a XT350 any chance the xt piston has the same G pin size and piston height from the pin I would near put money on it being a match but might need work on the valve pockets on the piston crown for the TTr valves to clear. And my hat is off to you for the time and money put into this I could have made a one off with the gear I have at home and work but it would have been at the limit on the casting we don't have that bigger Furnace/pot on are set up at the school it would not hold enough alloy to poor the thing.

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Way ahead of you there Martyn. Different gudgeon pin, compression height, valve reliefs, compression ratio... Price for custom pistons from Wossner is not prohibitive. We went through all this in minute detail before deciding to go ahead.
346 - Your maths is correct

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Cannot wait for this Simon, looks epic!!

Nice to know if i do this, i'm fairly local so can use your machinist!

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Hello from a very sunny Spain!smile

I think the cost of the kit is probably less than a couple of Katoom farkles so is excellent value if it delivers the torque we are expecting smile

Brian



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Very nice jobsmile the big difference against the 325 and this, is that there will be able to give one more re-bore on the sleeve, giving a vast amount of longevity against the thumper kit, that does not allow this. Also the the extra cc will be more than the thumper kit.

It may be a little more £, but much better valuesmilesmilesmilesmile

Now I need to get my Crankcases sorted!



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Just out of interest any idea on the power increase ?

I know the difference in power between the TTR & WRR & is it worth the money & effort required, does not stop with the bore as the carby would need a fair bit of work to provide the air / fuel ratio of the greater CC.
Years ago I used to modify my cars & bikes & would spend hours & hours to try & get it perfect, not having a go, just asking the question

Terry

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"Always with the negative waves Moriarty?"  (Kelly's Heroes) smile

Well I managed 27hp and 27Nm of torque from my 325 with practically no tuning (see the dyno in "325 kits what's involved" thread) Motad exhaust, minor airbox mods and smaller jets.

Until it's actually built I can't answer you!

I would like to see 30hp, but like I say, I'll start with standard exhaust, airbox and carb and play on the dyno. I expect it to run too rich to start with (the 325 does on standard jets) Mods I will try: freer flowing end can, maybe shorty header, different jetting, minor airbox mods. Eventually probably some porting work on the head. I think it'll need more air rather than more fuel (that's just my gut feeling) but the threads on alternative carbs make interesting reading for further experimentation.

Is it worth it? A chap's gotta have a hobby. I don't drink much, got no wife or kids, I like engineering projects. Yes, it's worth itsmile



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Hey no wife & kids, plenty of time for projects. 30HP would be good & I guess being a big bore the power increase would be low down. As for $$$$ bikes are not a good investment except for the mind. Then it's all worth it.

Any one remember the TT350, always wanted one back in the day, how does that engine relate to the TTR 350 big bore & it's a pity the 350  didn't continue, much like the XR400R I had, great power & wish I still had it.

Cheers Terry

 



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TT/XT350 and XR400 both excellent bikes (Yams let down by prehistoric suspension I believe) but both missing that electric leg. That's really what I'm trying to get to.
(I also have an XR400 with estart conversion that I'm playing with, but my 325 TTR handles better and is less complicated electrically.)

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I think the TTR handles better than the XR400R I had but unsure what it would be like with more power, BTW the WRR handles better again, I looked at fitting an electric start to the XR but the cost was huge

Terry



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I own TTR 250 and Suzuki DR 350. I had a chance to compare the cylinders. see the pictures. Seems like DR is smaller.

DR can be bored to 441cc or even to 480

http://dr350.wikia.com/wiki/Big_bore

 

It is probably cheaper and easier to buy second bike like DR 250/350 and bore it!



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honda15i wrote:

It is probably cheaper and easier to buy second bike like DR 250/350 and bore it!


 Quite likely but it still won't be a TTR wink



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TTRfan wrote:
honda15i wrote:

It is probably cheaper and easier to buy second bike like DR 250/350 and bore it!


 Quite likely but it still won't be a TTR wink


 We're TTR addicts.



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honda15i wrote:

I own TTR 250 and Suzuki DR 350. I had a chance to compare the cylinders. see the pictures. Seems like DR is smaller.

DR can be bored to 441cc or even to 480

http://dr350.wikia.com/wiki/Big_bore

 

It is probably cheaper and easier to buy second bike like DR 250/350 and bore it!


Nobody's stopping you smile 

I think the DR350 is a bit of an old slug, but that engine in the better TTR frame would make an interesting project.

For comparison Bore & stroke 79.0 x 72.1, 349cc, 30hp (claimed), CR 9.5:1



-- Edited by mossproof on Friday 5th of January 2018 05:11:03 PM

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Count me in when you get it sorted

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I hope its not to expensive to get the kit over here in Aus because atm 800 pounds is 1300 bucks and then import costs if i order it from you guys over in England if it gets to expensive i might just buy another bike to be honest. (I really dont want to) At the moment im paying for brand new CB500x so i cant really afford expensive mods

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I thought it would be a lot more to be honest, not being made in china.

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So is there a 350cc TTR up and running yet???

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You'll read it here first when there is

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mossproof wrote:

You'll read it here first when there is


 tease!



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Hope it won't be long before we are testing the first 2smilesmilesmile



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Good news. What compression ratio will the 350 be running?

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Sorry for the delay, been learning to ride sand in the Algerian sahara on my 325
I have requested approx stock CR from Wossner. Still awaiting some sort of reply from them regarding the order Wish I lived in the States - for many reasons, but in this instance so I could deal with Wossner direct rather than being forced to deal with a UK agent who's not really interested! Another reason would be so I could play in the desert without looking over my shoulder for beards in Toyota pickups with rear mounted HMGs!!
Simon.

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Any updates?

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Been waiting 5 months for Wossner to deliver (6-8 weeks they told me!!) I've just been pointed in the direction of JE Pistons via Cambridge motorsports, and have set them in motion for a quote. Hoping to get somewhere soon and looking forward to the possibility of dropping TSR Performance (UK Wossner agents). Small batch numbers is a difficulty, which is why I've not been able to "negotiate" faster.
Believe me, noone is more frustrated by all this than me. TSR don't return my calls, just get fobbed off by the desk dolly. Fingers crossed I'll get somewhere soon. Sorry for the wait.
Simon



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no Name and shame! Thats terrible customer service!

Could always call them out on Twitter etc.. Would probably speed them up wink

Dan, out in Serbia now, got wet in his new "Adventure Boots." Complained on Facebook/Twitter to the manufacturer and they're sending some new ones out to him!



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Just appreciate your hard work Simon.

Result with the boots tricksmile



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That's such a joke Simon! Hopefully JE Pistons save the day!

It'll be worth it when you see a fleet of ttr250s lifting those front wheels in 6th gear 😆



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You have the patience of a saint Simon!

Thanks for sticking with it.

Wossner have let us down very badly evileye



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Is this the Holy Grail?

Pistons arrived from Wossner today (via TSR Performance). The story is Wossner moved factories in Jan and ended up with a huge backlog of work. Would have been nice to have been told that back in Feb, rather than treated like a mushroom, but there we are. I've now got 4 shiny 86mm pistons in my grubby mitts. Off to the machine shop to bore the sleeves and away we go.....

P1010802.JPG



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The excitement is killing me!!

Cant wait!

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I'm wiping the drool off. Awesome. :)

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I hope it all goes well, wea need the extra cc in our lives haha

Looking forward to hearing how it goes!

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Wow - the Holy Grail has been found!  biggrinbiggrin

What great news to wake up to Simon.

You will have to warn those chickens that they will have to find a new home wink



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Yes yes yes, better get my crankcase sorted ASAPsmile



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I'll get the barrels down to the machinist this week Steve, then send you one down so you can get the hole bored out properly.

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How exciting

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Very nice!

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Oh yes this is good news

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Can't wait, so excitedsmilesmilesmile



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Well it all fits together and the crank turns smile

P1010804.JPG



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Please make a video when you start the engine and do first ride



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Great too see! Keep up the good work, we are all excited Simon!

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