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

Gadget964 · Veteran Member

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

TerryK · Super Guru

Good luck with the 24hr, it gets bloody cold out there overnight so get him to have layers that can be removed as he warms up. Make sure you use DOT tyres & the lights are up to the task.

Phil from Motorbiking is riding a TT250R this year so we should have at least 2 x TTR's out there proving he can get into SA from Queensland !!!!

Cheers Terry

Gadget964 · Veteran Member

I rode the 24 in 2006 on a TTR 250- finished with a class win... The only difference with this bike is using LED lights instead of halogen. My bike has just come through a roadworthy, so we know that it's right to go. Motoz Tractionators this year.

Unfortunately I have heard that Phil has fallen victim to the Covid lock downs and will be unable to make it.

Gadget964 · Veteran Member

Scrutineered and ready to go.

mossproof · Super Guru

Good luck Liam!

TTRfan · Super Guru

Looking like a winner already! Good luck boys wink

ttr steve · Super Guru

Hope you smash it win that is !

TerryK · Super Guru

My mate ( he also has a TTR) rang me last night to see if I wanted to come up, he's on one of the check points, I told him to keep a look out for the TTR350

Good luck & keep warm

Terry

Gadget964 · Veteran Member

Thanks for the messages guys, they have been passed on to Liam. I almost forgot they have live timing this year

my.raceresult.com/171719/Live

There is 15 riders in Liams class (F), most on excf 350's.

dlee22 · Senior Member

Good luck! Go smash those Ktms! Haha

Gadget964 · Veteran Member

After 12 hours of racing, Liam withdrew from the event.

1/3 the way through his second lap he was looking pretty good, despite having been thrown a few times (largely from last minute changes to the front end that we had to make due to a cracked front rim... Complete front end change) . Coming in from his second lap (at 1 am) we could tell that he was done. As he put it "racing Hattah last week wasn't a good idea" (4 hour desert Sprint on 38km track). Fighting with the different front end on a rapidly deteriorating track just exacerbated everything that he'd felt since the previous race.

On the up side, the 350 ran beautifully for pretty much 12 hours solid, and we had full confidence that it would easily make it to the end.

TerryK · Super Guru

Bad luck but it is a ball breaker event

Cheers Terry

TTRfan · Super Guru

Well done Liam - and the 350 motor! 12 hours racing was probably the best test yet and Steve probably ought to add it to the sales blurb wink

ttr steve · Super Guru

Well done Liam for getting that far! Amazing test of man and machine and glad both came out unscathed smile smile

Good news for the 350 owners out there.

mossproof · Super Guru

Better to stop voluntarily than be stopped by an exhaustion induced crash! Damn good effort even making the start after Hattah. Well done and I'm glad the 350 didn't let you down

Incidentally, batch of six barrels came back from the foundry today. This may be the last batch as demand slows and the outlay weighs heavy on my bank account...

Gadget964 · Veteran Member

On the drive home, Liam was going through his footage, and has put a Youtube video together. (There is a little bit of swearing in the video)

In watching the footage, it's worth noting that prior to starting, the bike had been locked in Park Ferme for 22 hours- and wasn't permitted to be started until his departure time... Firing up for the second lap is at 14 minutes (give or take). I am very happy with the way the 350 started and ran throughout the event.

At the time of withdrawing, he was coming 72nd of 146, and 7th in class...

www.youtube.com/watch

Dlight10 · Newbie

Well done to both man and machine, that was a top effort mate! Great footage too.

-- Edited by Dlight10 on Tuesday 13th of July 2021 06:34:31 PM

-- Edited by Dlight10 on Tuesday 13th of July 2021 06:48:58 PM

TerryK · Super Guru

Great video, love the video split between day & night, lights were pretty good as well. No shame in pulling out I know plenty of guys that have taken a few years to finish the event, they learn the mistakes with what to carry & wear. But at least it was dry this year, in other years it has been very wet & would be the worst weekend during the year weather wise.

The bike seemed good with plenty of sandy loam, got to watch water holes & stick to the left, sidecars dig huge holes on the right.

Cheers Terry

Kaos · Senior Member

mossproof wrote:
Better to stop voluntarily than be stopped by an exhaustion induced crash! Damn good effort even making the start after Hattah. Well done and I'm glad the 350 didn't let you down

Incidentally, batch of six barrels came back from the foundry today. This may be the last batch as demand slows and the outlay weighs heavy on my bank account...

Mossproof/Steve put me down for a kit please. I was going to put it in my TTR263 but that bike goes too well. So I am building another one to replace my Wrf. Twin TTR'S!!

Gadget964 · Veteran Member

Going for a PWK again on this one? Should fairly easily hit 40hp.

Kaos · Senior Member

Gadget964 wrote:
Going for a PWK again on this one? Should fairly easily hit 40hp.

Yeah PWK38. Scotty already has a new one ready for me! I dunno about 40 hp aim to crack 30+. With just some head porting and with trick exhaust and suspension. The 263cc bike is actually my sons bike I comandeered! Time to build my own.

Gadget964 · Veteran Member

Yeah, 30.

mossproof · Super Guru

Don't blow the bottom end !!!! 30's a good enough target.
Latest batch are at the machine shop next week, but Wossner are being coy at the moment...

Kaos · Senior Member

mossproof wrote:
Don't blow the bottom end !!!! 30's a good enough target.
Latest batch are at the machine shop next week, but Wossner are being coy at the moment...

Ha ha no it will remain pretty stock just bigger carb massaged head and better exhaust. Might play with different headers. No hot cams or anything. And no hurry from this end its all got to be build from a pile of parts that all need to be reconditioned and reassembled, motor rebuilt etc. As long as one has my name on it!!

-- Edited by Kaos on Monday 19th of July 2021 11:36:58 PM

mikemikettr250bike · Veteran Member

mossproof wrote:
Better to stop voluntarily than be stopped by an exhaustion induced crash! Damn good effort even making the start after Hattah. Well done and I'm glad the 350 didn't let you down

Incidentally, batch of six barrels came back from the foundry today. This may be the last batch as demand slows and the outlay weighs heavy on my bank account...

Hi, Reference demand is low:

Apart from the forum, have you actually got much social media advertising out there? I find it hard to believe that the demand would be low!

mossproof · Super Guru

Actually small batches are hard enough to get produced and I find it quite stressful on behalf of the buyers - lead time is up to 8 months and at the mercy of foundry, machinist and Wossner/EU customs.
It's also a big outlay for what is an old style bike and requires commitment - financially and spiritually! Far more people talk about fitting one than come up with the money, and my (limited) knowledge of social media suggests there would be a lot of hot air blowing in totallyttrs' direction with idle enquiries. If they've found this forum then at least that shows a bit more gumption than just clicking on a hashtag, firing off a "how much, what do I have to do to my bike, do you fit the kits for me..." type stuff. The harder the path, the greater the reward grasshopper

ttr steve · Super Guru

Mikes Kit is being sent in the morning, grasshopper made me laugh and shows your age Simon !

Only 2 kits left now wink

mikemikettr250bike · Veteran Member

ttr steve wrote:
Mikes Kit is being sent in the morning, grasshopper made me laugh and shows your age Simon !
Only 2 kits left now

GGLLAAASSSS hopper , hey thats not old !!!!

mikemikettr250bike · Veteran Member

mossproof wrote:
Actually small batches are hard enough to get produced and I find it quite stressful on behalf of the buyers - lead time is up to 8 months and at the mercy of foundry, machinist and Wossner/EU customs.
It's also a big outlay for what is an old style bike and requires commitment - financially and spiritually! Far more people talk about fitting one than come up with the money, and my (limited) knowledge of social media suggests there would be a lot of hot air blowing in totallyttrs' direction with idle enquiries. If they've found this forum then at least that shows a bit more gumption than just clicking on a hashtag, firing off a "how much, what do I have to do to my bike, do you fit the kits for me..." type stuff. The harder the path, the greater the reward grasshopper

Makes sense, anyway thanks for all you hard work. I have had at least 50 bikes (most dirt biased) I have gone full circle back to the some what older design as it just works better as a less maintenance, less tiring ride!

It just lacks that little bit of extra grunt to keep up with the fellas on there modern bikes. Hence the 350!!! that should see me right.

The new Hagon development shock and the KYB forks should sort out the rest of my niggles..............

I will keep you all posted on my progress and testing etc.

Thanks again for all of your hard work and dedication.

mikemikettr250bike · Veteran Member

Advise welcome please:
I now have a spare set of cases in my mits to get machined now. 4GY00
They are slightly different to mine 4GY02........... (blue) there also this where on mine its blanked off. I am presuming that will be the only difference and I will not come across any differences that might affect me once i am ready to swap over the insides.

mossproof · Super Guru

As far as I am aware that (crank breather) is the only difference. If you can wangle in another centrifugal breather filter somewhere and introduce it to the air filter box somehow, I'm sure it would help the crankcase breathing - 100cc extra going in and out with every stroke of the piston is a lot for the standard pipework!

If you choose to block off one or other, be aware that there is more oil mist coming from the crank cases than the head/cam gallery - the breather drain pipe gets more oil in it on the oe/raid 350s than the blues.

I have yet to find a system that can separate the oil mist and return it to the crank case rather than blowing it out as waste. There must be something out there? But then, sometimes there is an emulsion when running in humid conditions, so you don't want that returning to the sump... Nothing is ever simple is it?

JOHNYBOY · Super Guru

why not vent it to atmospere up the frame & to the back like they did on a lot of british bikes

mikemikettr250bike · Veteran Member

Thanks for the advise, it well may be a blessing then? I will keep the head vent as is and then add the case vent into the build somehow.

mossproof · Super Guru

JOHNYBOY wrote:
why not vent it to atmospere up the frame & to the back like they did on a lot of british bikes

Well the breather sucks as well as blows - every time the piston goes up and down, so you risk drawing dust/water into the crankcases, quite apart from the oily mess that will build up (not a problem with old British bikes, which were an oily mess from the factory

mossproof · Super Guru

Finally came across an official manufacturers break-in procedure from Wossner:

cdn.shopify.com/s/files/1/2030/3551/files/WTB.00003-B_POWERSPORTS_BREAK_IN_INSTRUCTIONS_06-23-2021.pdf

If that link doesn't work go to www.wossnerpistons.com/pages/faq-and-helpful-forms

Quite a handy page! Ryan F9 on the 'tube is also a handy resource:

www.youtube.com/watch

Gadget964 · Veteran Member

Hi all,
It's been a while, so I thought that I'd give an update on the TTR350 (TT retro look).

This motor continues to run exceptionally strong. Starts easily, and never misses a beat. Since running in the 24 Hour Reliability Trial, all that I've had to do to it is change engine oil and swap air filters. The Mikuni TM33 hasn't been touched since the dyno runs... Summer or winter, it just starts and runs well.

Now that I am not using it in the desert much, I've changed back to my TTR250 forks with gold valves (TTR600 forks changed the rake too much for the hills.) The bike has recently been changed to historical registration, which is for vehicles over 25 years old. It continues to draw a lot of attention wherever it goes......

While setting up his own bikes for other events, Liam decided to use the 350 at a round of the Diamond Valley MCC enduros at the Sanders Apples property near the Yarra Valley (Home of Daniel "Chucky" Sanders). It was the only bike that demanded any attention. Both fork seals blew (18 years old- so they were way past due), the headlight bolts came undone, leading to the headlight falling off (which he picked up and carried back to the pits on the following lap), and the headstem came loose and needed to be secured. Despite this, Liam brought the old girl home in 55th (of 74). Hopefully he will have a video of the event set up soon.

mossproof · Super Guru

Thanks for the update. Good to hear things are running well (including the carb mod).
I don't think I'm a sensitive (or fast) enough rider to feel the benefit of gold valving the forks, but as I've more or less run out of other things I want to modify, I suppose I should try!
Cheers,
Simon.

Gadget964 · Veteran Member

Turns out that the 350 is getting raced again tomorrow. It'll be an enduro sprint round this time (near Tallarook, Victoria, Australia).

After blowing the forks last week (and having no time to get them serviced), we were going to fit the WR200 front end on, but the WR front wheel needs a few spokes..... So we "borrowed" a set of forks off my mates TTR.

rbraz1980 · Veteran Member

Hi!

What is the highest mileage 350 out there?

I am going to build an engine soon and the 350 is tempting, but worried about long term reliability...

Thx

R.

Gadget964 · Veteran Member

Mine has still only done about 2500km..... but over half of that has been under race conditions. For those new to these pages, I fitted the 350 kit to a 1996 TTR250 (what you guys call an OE), then added TT350 tank and race plates.

The following links are from my sons vlog thingy. There's a bit of talking, but also some raw footage to see the 350 in action.

www.youtube.com/watch
www.youtube.com/watch

Forgorin · Senior Member

Mine has about 15,000km on it now.

Actually, I'm posting here 'cus I need new piston rings... and new gaskets.... I am not sure what i have done to it, besides ride it hard. Perhaps a bit too hard. I have a feeling I might have been over revving it. She is burning oil at quite a rate. However it's only when the chamber is .... Argh... I cant think of the word! Under decompression? It only happens when I am not accelerating. For example when I use engine breaking. It is sucking oil up.

I haven't opened it up yet to see just what might be causing it. I am gonna wait until I get new rings and gaskets. Gonna call Steve real soon!

Otherwise, the bike is a real blast to ride. Like Gadget964 said, it's an eye catcher.

Michael

Jeff B · Senior Member

I'm guessing that if you are pulling in oil on decompression then it has quite a bit of vacuum. No loss in power would indicate the rings are probably ok. I recommend a compression test to confirm. If compression is good, then there is a possibility that oil is being pulled in via the valve guides. Have they been checked for excessive clearance?

dlee22 · Senior Member

Interested what you find Michael as I am about to strip my 350 die to oil use.

Interesting thought Jeff, I didn't check mine when I rebuilt my motor, hope they are easy to change

Jeff B · Senior Member

Daniel,

I've never replaced them but I did try removing them from a junk head. They pressed-fitted in tight! Alot of heat is needed to remove and replace. An engine builder told me that he uses a special fitting tool to insert the guides at the proper angle.

I'm sure Brian or Steve could provide some more insight.

Forgorin · Senior Member

I'll try and find somewhere to do a compression check. I think I read somewhere that it should still be pretty close to stock. Humm... I thought I had the valve guides rebuilt when I did the 350 install. I'll ask the mechanic I went to if he remembers....

I'll get back to you guys with what I find.

TTRfan · Super Guru

In all my years of messing with TTRs and their engines (and that was a lot of engine rebuilds), I have never come across a case of guides being worn enough to warrant replacing them. Which is very good because I have had to replace guides on my BSA C15 and that was a whole world of pain requiring drifts, reamers and a lot of patience!

Worn valve stem oil seals usually only cause a bit of smoke on start up and not contribute to higher oil consumption.

Smoking on the overrun is invariable caused by worn or damaged piston, rings or cylinder bore. Out of interest, were the ring gaps properly spaced i.e. not all in a line?

Brian

Forgorin · Senior Member

Brian, I don't remember. I have a bit of a memory of someone telling me to make sure they weren't lined up.

dlee22 · Senior Member

At the risk of sounding stupid (not too hard for me) has anyone had a breather from there crank casing and put a bluey cam cover on and combined the two pipes to help the larger 350 piston "breath" better?

TTRfan · Super Guru

dlee22 wrote:
At the risk of sounding stupid (not too hard for me) has anyone had a breather from there crank casing and put a bluey cam cover on and combined the two pipes to help the larger 350 piston "breath" better?

I have thought about it but haven't done it Dan. Sounds like a plan. No need to join them - just leave them as separate pipes.

Thinking about it, I used later crankcases without the crankcase breather.

dlee22 · Senior Member

I think I'll need to join them by the emulsifier?

I have everything to try it, my ttr250 oe used to collect a reasonable amount on long runs on the road