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

petenz · Super Guru

RE: 350cc Big Bore Kit for the TTR250 - updates and gossip!

shad · Veteran Member

sweet cant wait till it goes retail its killing me hopefully the cost to get it to AU wont be to expensive

mossproof · Super Guru

10.9 is rich Pete. Stoich is 14ish and lean is above that, but I refer you to the link to AFR readings which I have been using for guidance:

www.safrtool.com/SAFR-AFR-values.asp

ttr steve · Super Guru

Runs mostly 12.5 only 10.9 at very small point of rev range (taken the AFR off now)

Never seems hot and feels perfect to ride smile

dlee22 · Senior Member

Any update on the kits and how you guys are getting in with them?

ttr steve · Super Guru

Kits are sweet and the bikes pull like a train, I have been struggling to get some miles on my bike (family stuff) but loving it so far smile there are 6 on order and should be in the shop soon(ish)

mossproof · Super Guru

Pistons 5 weeks into the order lead time.
Barrels been in the machine shop 2 weeks.
Head gaskets ordered last week, 3 week lead time.
We're all learning patience on this project!!

TTRfan · Super Guru

mossproof wrote:
Pistons 5 weeks into the order lead time.
Barrels been in the machine shop 2 weeks.
Head gaskets ordered last week, 3 week lead time.
We're all learning patience on this project!!

The lucky customers won't have to put up with any of that as, in due course, they will be able to buy the kit straight off the shelf from Totally TTRs biggrin

TTR Keith · Member

Steve - et,all..

Have you been able to figure out what you will be asking for a full kit yet?

... Inquiring minds want to know!

Keith

Forgorin · Senior Member

Here's an odd question. How much does the whole kit weigh?

ttr steve · Super Guru

TTR Keith wrote:
Steve - et,all..
Have you been able to figure out what you will be asking for a full kit yet?
... Inquiring minds want to know!
Keith

Still yet to finalise the retail price.

tripodtiger · Senior Member

Forgorin wrote:
Here's an odd question. How much does the whole kit weigh?

Bigger hole, should weigh less!!

Forgorin · Senior Member

tripodtiger wrote:
Forgorin wrote:
Here's an odd question. How much does the whole kit weigh?

Bigger hole, should weigh less!!

Hahaha. I've got a friend who might be willing to take it as carry on next time he flies out to see me. Hope it's not too much...!

mossproof · Super Guru

Piston weighs 334g inc rings and gudgeon pin. Compare that with oem piston of 265g.
Barrel approx 1.7kg and is 19x17x11cm. Haven't got a loose 250 barrel to compare.
Currently about to fall out with my machinist...

Kaos · Senior Member

It would be interesting to see a dyno run of the 350 vs a 250. biggrin biggrin

mossproof · Super Guru

Scroll back to page 3 of this thread for dyno of the engine as a 250, then 350 with standard pipes etc. biggrin

Machinist has a broken patella thanks to damn diesel leaking tintop on the road 40 yards from his home. cry

Kaos · Senior Member

Thanks I didn't see the 250 part. Don't know if it was the speed reading or the Alzheimer's.

Forgorin · Senior Member

Any updates...?

mossproof · Super Guru

I have sold all my tools and bikes and taken up knitting fog...

ttr steve · Super Guru

biggrin biggrin biggrin

my 350 is running well, taking it to Wales 1st bank holiday in May, with 2 or 3 other ttr's.

machinist for the barrels is on a bit of a go slow, but hopefully they will be done soon and ready to sell.

I have just received the gaskets for them. smile

TbirdX · Veteran Member

Steve, are you going to Welsh Wales for the Taffy Dakar?

ttr steve · Super Guru

not the taffy Dakar, but will be doing my own th8ng nearby..

you going?

TbirdX · Veteran Member

To the Taffy, yes.

Ahhh, I was hoping for a cheeky spin on the 350

.

Lets hope the weather holds for that weekend.

ttr steve · Super Guru

I will be in llandovery Friday afternoon, you would be welcome to come and have a ride.

TbirdX · Veteran Member

I was half joking

but thats very generous of you. I won't be around until late Friday myself, maybe we'll meet on the lanes!

robs · Senior Member

I have a set of crank cases available which would be perfect for the 350 kit when it is available, please see: ttr250.activeboard.com/t65515306/for-sale-pair-of-matching-crankcases-from-20045-ttr250/

Gadget964 · Veteran Member

Hi guys, it's been quiet in here lately. Any progress?

mossproof · Super Guru

Fog knitting just wasn't cutting it for me, needed something more challenging so I've sold me needles and taken up cat herding. Specifically Burmese and Siamese.

Honestly, because I went for small local engineering firm I'm now playing the waiting game but the price for the work (when it's done) is reasonable. I want this sorted as much/more than you guys - I'm sitting on 1200 quids worth of pistons that don't fit ANYTHING else in the world!

Sorry sorry sorry.

dlee22 · Senior Member

Hang in there Simon, sure it'll be worth it!!

Gadget964 · Veteran Member

If it makes any difference to your financial outlay- I'm prepared to put a deposit on a kit. (Without even knowing what the total cost will be) As long as you are prepared to ship to Australia.

I've come up with some really big/dumb ideas for the 1996 model that I have in the shed.

-- Edited by Gadget964 on Sunday 21st of July 2019 11:03:02 AM

tripodtiger · Senior Member

"really big / dumb ideas"

confuse

wink

evileye

biggrin

-- Edited by tripodtiger on Saturday 27th of July 2019 12:01:31 AM

-- Edited by tripodtiger on Saturday 27th of July 2019 12:01:58 AM

-- Edited by tripodtiger on Saturday 27th of July 2019 12:02:19 AM

Gadget964 · Veteran Member

Umm, yeah.

Back in the day I raced my TTR in the Finke Desert Race, as well as the 24 Hour Reliability Trial (for those not from around here- there are many youtube clips).

Dad had a pretty standard 1998, I had the 1999 that I'd tweaked. Suspension was the big gain; although standard to look at, the internals had been modified to suit me, and made a huge difference to the way the bike behaved. By the time I was done with it, I was getting about 28hp at the knobbie (I have the dyno still floating around here somewhere). I dearly wanted to go to the 325, but couldn't justify it for what I wanted to do...so the TTR was sold in 2007 to make way for a DRZ400 that I raced in the Australasian Safari in 2009. With a new suspension tuner, and a better base suspension, the DRZ was a brilliantly handling bike.... but I'm partial to my Yamahas. Dads old TTR is still in my shed, but now owned by my mate.

Anyway; last year I found that my old TTR was for sale- having only done about 500km since I sold it- my son ended up buying it for his daily ride (he actually raced flat track on it last week as well). To get more adjustability in the suspension he swapped the forks out for a DRZ front end. Getting back on my old TTR and riding just feels so natural to me. Which is where my dumb idea started to form:

With these guys developing the genuine 350 kit, I began to see that I could get the bike that I always wanted: electric start, air cooled, and more Hp than the TTR had. So I bought a 1996 in need of attention & stripped it. My son stole the plastics (because he loves the retro red/white look of the late 80's TT- as do I). One of the big things in my favour, is that I now had my original suspension back. So the plan was to freshen the junker up with a 350 & my suspension...

No longer the plan. It'll probably be cheaper for me to go buy another 400 or something- but this is now something that I just want to do. BUILT, NOT BOUGHT.

By the time I'm done, this bike will have a fresh 350 motor, with really-really good suspension (as mentioned, I have a good suspension tuner)… and will probably look more like a TT250 than a TTR250.

If I can achieve all of this my plan is to ride it where, by todays standards, it just does not belong.... in the Hattah Desert Race.

Kaos · Senior Member

Gadget964 wrote:
Umm, yeah.

Back in the day I raced my TTR in the Finke Desert Race, as well as the 24 Hour Reliability Trial (for those not from around here- there are many youtube clips).

Dad had a pretty standard 1998, I had the 1999 that I'd tweaked. Suspension was the big gain; although standard to look at, the internals had been modified to suit me, and made a huge difference to the way the bike behaved. By the time I was done with it, I was getting about 28hp at the knobbie (I have the dyno still floating around here somewhere). I dearly wanted to go to the 325, but couldn't justify it for what I wanted to do...so the TTR was sold in 2007 to make way for a DRZ400 that I raced in the Australasian Safari in 2009. With a new suspension tuner, and a better base suspension, the DRZ was a brilliantly handling bike.... but I'm partial to my Yamahas. Dads old TTR is still in my shed, but now owned by my mate.

Anyway; last year I found that my old TTR was for sale- having only done about 500km since I sold it- my son ended up buying it for his daily ride (he actually raced flat track on it last week as well). To get more adjustability in the suspension he swapped the forks out for a DRZ front end. Getting back on my old TTR and riding just feels so natural to me. Which is where my dumb idea started to form:

With these guys developing the genuine 350 kit, I began to see that I could get the bike that I always wanted: electric start, air cooled, and more Hp than the TTR had. So I bought a 1996 in need of attention & stripped it. My son stole the plastics (because he loves the retro red/white look of the late 80's TT- as do I). One of the big things in my favour, is that I now had my original suspension back. So the plan was to freshen the junker up with a 350 & my suspension...

No longer the plan. It'll probably be cheaper for me to go buy another 400 or something- but this is now something that I just want to do. BUILT, NOT BOUGHT.

By the time I'm done, this bike will have a fresh 350 motor, with really-really good suspension (as mentioned, I have a good suspension tuner)… and will probably look more like a TT250 than a TTR250.

If I can achieve all of this my plan is to ride it where, by todays standards, it just does not belong.... in the Hattah Desert Race.

Gadget,

Loving your dumb ideas. I too have some professionally "Built" suspension in the shed waiting for a second TTR project!!!

How did you get 28 HP I'm very interested, mine did 23.5 and thats fun (Ported 263, shorty header.) I also ran a DRZ back in the day, a 2000 kicker ex thumper nats bike. I still have a couple of DRZ motors but I like the TTR's better ride in the Victorian bush.

As for Hattah, you'd enjoy the 1st lap or 2 but then it gets rough as guts. Dunno if I'd be game on the TTR, it would do it but I'd want something 20 kg lighter I think new WR would get a run.

It would be cool to see a TTR on the start line though

tripodtiger · Senior Member

I like the idea too. Not too dumb.

I've not been the type to do such mods. I bought a couple of Katos over the years so the good suspension was already part of the deal.

As I get a little older, with time on my hands, I'm thinking I may be able to do some tinkering and parts swapping. Lots of projects. A bloke I've been road racing with and I have been wondering about the possibility of dropping 350LC top end and radiator onto an RD400 bottom end. External electric pump, like on my 350 race bike, would cover the pump that's missing from the 400. Thinking out load.

I love the 24. Best event in Australia. I've not been to watch for the past 3 years though. Maybe next year, we'll see. For the non-Antipodians, South Australia is the home of road trials. Solos & sidecars, road registered, raced in the endurance events of competitive sections and transport sections. 6 hours, 12 hours, 24 hours. The 24 is second oldest competition event to the IOM TT. Hundred years old soon. 4 laps of around 200km, although this year was somewhere around 170km.

Sorry, off topic. Just got sidetracked.

Gadget964 · Veteran Member

Kaos, you were almost on it. Mild port & polish, 2nd over, high comp.... when we had it at the dyno I had several runs- the best I achieved (and still needing jetting changes) was with the snorkel completely removed, and airbox opened up a bit more (which, in all honesty, is a pain in the ass when it's dusty). Matching a Staintune shorty header with the Webbys muffler brought the best results.... The bike is still running that combo.

Here's some interesting stats for you. My son races Hattah on a WR200 (2st). When I brought the bike home this year I weighed it. In full race trim, with 1/2 tank fuel, it came in at 111kg. Dads old TTR, with steel tank, original headlight & ADR crap, battery and starter motor was only 14kg heavier. So I can get the TTR weight down to a very respectable level; in reality I'm thinking about 10 kg difference to a stripped down 2 stroke. My real issue with competing Hattah (why I never have) is old CFA injuries, but I think that I'd be able to put on a good show if I had to. As my son mentioned one day... "Nothing pisses racers off more than being passed by an Ag bike"

TTR Keith · Member

Gadget, what were your dyno run numbers, if you don't mind sharing that info with us? I've put custom ground cams into my TTR.. wow, they really woke the engine up. I'm using a 1mm over bore, opened air box, twin air air filter, WR250F muffler with Super Trapp end plates and open end cap... and a highly shaved flywheel for quick revs. This all works really really well. 350cc will just be the icing on the cake... a true, twist the throttle, wheelie monster of a TTR. I compared our TTR250s to the stock 2004 DRZ250... and saw almost identical specs and build at every comparison, except the DRZ250 makes 3.5 more hp out of the gate. My TTR250 is running Yamaha YZ250 USD forks... so my bike really is closer to a DRZ250 than we could say a stock ttr would be. I can't think of anything else I can do to my bike to get more HP and torque with, other than a 350cc kit. Except you mention a Staintuned pipe. I'm not familiar with that item! Hoping that you can remember your dyno run numbers!

Gadget964 · Veteran Member

It turns out that I sent the dyno to Mildura with my son (now his bike) I'm trying to get a copy back.

When I was getting my DRZ400 dyno tuned, the tester made an interesting point- that very few dynos would give the same result, and that the results that they do give can be dependant on how the dyno is set up, humidity and so on... so the results can change from day to day (sounded feasible at the time) He said that the main conclusions that you can come to can only be against the other runs that you have done in the one session (eg: I did successive runs baffle in/ baffle out.... on the day baffle out made 1hp more). Relevant information at the time. It also helped me with the tuning initially.

The main focus for me is the 'seat of the pants' feel. Past knowledge - there can be significant gains over the standard motor (keeping in mind that I still have a stock bike in the shed for comparison). The 350 cc kit that these guys are developing is going to make the TTR an absolute hoot to ride. Approx 40% more cc is bound to make a huge difference. I'm really not caring about the numbers- as long as I get it tuned properly...……

But first we all have to wait with bated breath for the TTR350 kit to become commercially available.

mossproof · Super Guru

News coming soon on the 350 kit folks!
I've had a few problems with the foundry work which has only just shown up in the machining so I didn't have the batch size I was hoping for (just 2 passed quality control!!!) but I've now found another foundry with much shorter lead times and things are looking up, fingers crossed.
I just have to do some number crunching when the new foundry has done a proof casting and we'll be away.
TotallyTTRs will be sorting the retail and dispatch, so no pms to me please.
Watch this space...

Gadget964 · Veteran Member

Great news... I'm so excited about this.

Please let us know when we need to annoy the Totally TTR's website.

ttr steve · Super Guru

There is only 2 that will first be available - the other 2 are promised to Brian and another investor in the project (there was 4 of us who got this off the ground) (though mostly thanks to Simon)

We are going to order another 4 more very soon.

We think it is right that the first 2 are offered by way of a hat draw, rather than putting them in the shop, as the time difference may disadvantage our overseas customers.

Anyway hands up for your name in the draw!

Cost will be £795

This includes the piston / Barrel / gaskets. You will need to get your crankases macheined to take the bigger sleeve, but the rest is bolt and play!

This is nothing like the 325 that thumper racing do at about the same price (I think)

This has a whole new barrel cast that is so much better, as the 325 has been bored out to the max using your old barrel. Where ours has longevity, as with the bespoke casting there is enough material on the sleeve, that a re-bore can be done if ever needed, some time in the distant future.

Any questions feel free to ask.

Steve

Pikey15 · Member

This is fantastic, thank you guys for all your work so far.

dlee22 · Senior Member

Hi Steve,

How do you get entered into the hat draw and do you have anyone recommended to shave the crankcase down?

Thanks

ttr steve · Super Guru

Hi Dan

The draw for the first 2 is just by confirming on here.

Any local guy to you really, it is an easy job and cost me £38

mossproof · Super Guru

Really glad this is finally coming together. It has been a long and frustrating road!

Here's a quick teaser photo. Please note that the limitations of sand casting, as opposed to the Yamaha die casting, mean the fins are slightly fatter than oem, and the surface texture is not as smooth. It responds well to a bit of filing and sanding though, but for me to start doing that would add a lot of extra labour to the costs. We will leave it to the purchaser to fettle as far as they see fit., and when in place, there is very little noticeable difference anyway.

Another batch is on order already from another foundry, who appear much faster. Serves me right for first going to the sleepy rural backwater of Stroud rather than direct to the heart of British manufacturing in the Black Country. Then we just have to hope the machinist doesn't break another leg, and his kidney stones "pass" easily cry

ttr steve · Super Guru

And more power than the 325 smile

The torque is really incredible on my 350 smile

dlee22 · Senior Member

Have you had any new figures to compare against the 250?

Eg power/torque/mpg etc?

ttr steve · Super Guru

Earlier on this thread there is the dyno readings showing what you need to know.

The extra torque is massive, uphill 5th gear and twist of the throttle and pulls away smile

Not sure about the mpg, as I would rather have the extra power and have the Acerbis fitted wink

TTRfan · Super Guru

Simon said he was getting 65mpg with aggressive use of the throttle biggrin

KiwiJeff · Senior Member

Gee Mossproof you deserve a medal for persistence on this project, very well done.
I saw one on Steve’s bike during our visit to his and Lisa’s “Hostel” in July and it looked fantastic.
Didn’t take it for a spin as the Travel Insurance probably wouldn’t have covered “Injury by Motorcycle.”
Good idea to leave the final fettling to the individual Purchasers.
Again, bloody well done.
Cheers
Jeff

mossproof · Super Guru

Thanks Jeff. It's been a challenge to maintain morale, but the encouragement on this forum has been great.

@Dan: I swapped the oem exhaust for an FMF Q4, took the airbox lid off and did some jetting and got 25.5 hp @7500, and 21 ftlbs @ 5500. I have not done any porting or polishing and for that to compare so well with the Euro spec Honda CRF450L that costs ten grand I'm really happy!! When I first built my 350 I was braaaping around all over the place just playing with the torque band up and down the revs - not smooth riding at all, and after running in, the first tank refill gave me 65mpg (UK gallons) Since then I haven't measured it again, but more controlled use of the throttle would improve this hugely - I was hooligunning it!

So here we have it folks:

A genuine 346cc – nearly a 100cc increase! The Thumper Racing 325 kit is actually only 315cc.

Newly cast barrel so you can sell your old one to help fund the kit!

The barrel has a thicker wall than the original so that, when bored to take the sleeve, it still has plenty of meat left. No oil weeps through cracks in the barrel as has happened to quite a few owners who have used the Thumper Racing 325 kit.

New liner/sleeve with sufficient meat on it to allow for rebores if ever needed in the future.

Quality Wossner pistons (made especially for the kit) together with excellent Cometic gaskets are supplied in the kit.

The only machining work needed by the customer is to bore the crankcases to take the bigger sleeve. Most engineering workshops can do this and it’s not expensive. Circa £30 to £40 in the UK.

No need to modify the cylinder had or other parts although owners are welcome to improve the airflow by modifying the airbox, gas flowing the head, using modified camshafts with different lift and profiles, free-flow exhausts, shorty headers, larger bore flat slide carbs, etc. Feedback on any such mods will always be appreciated via the TTR250 forum.

I think there will be a lot to gain from porting and a bigger/bored carb, for those on the hunt for power. For me the lovely wide torque curve is what makes it such a nice ride so I'll stick with standard carb and a Motad pipe. I look forward to hearing what others can achieve with tuning...