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

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


Super Guru

Status: Offline
Posts: 1017
Date:
350cc Big Bore Kit for the TTR250 - updates and gossip!
Permalink  
 


TTR350 number 4 rode out of the garage this morning with all 6 gears! It rode out yesterday with only 1 - misaligned selector, oops!
Now for some illicit lockdown running in. Back roads only ha, they'll never take me alive...

Gadget your's will be a ktm killer for sure.

__________________


Super Guru

Status: Offline
Posts: 8056
Date:
Permalink  
 

Well done Simon!

I will get going on mine again once I have finished my gardening duties (Dig for England!) - or the rain returns.....

Brian



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ! 
 

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 



Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

Well: I managed to get my motor to my mechanic for its rebuild just before the beer bug shut us down. So even if he manages to get it all milled and rebuilt, I can't get near the bloody thing (450km away) due to travel restrictions (I did hear talk of May 11 over here today)… so I've been working on getting the frame ready to receive its new heart.  

TTR600 headstem fits in nicely. I just have to weld in a new steering stopper, which I fabricated today. Hopefully I'll be ready to prep and paint the frame within a week. And have it all sitting here waiting.  I've decided against fitting the oil cooler just yet as the motor may end up in one of our other bikes for some reason.  Once it's all dialled in I'll make a decision about the cooler.



__________________


Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

Frustrating!
I would definitely fit a cooler, whichever bike it goes into, considering the extra performance mods you're going for, and your climate. More oil capacity and cooler oil gotta help, but certainly not essential for initial setup.
Here's the cooler I've built for #4. Slightly bigger than ideal for the gap it fits in (damn that Acerbis is huge!) but it holds a lot of extra oil. (85ml)

                    1.JPG


 






__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

One thing that I am considering with the oil cooler, is how much riding am I actually going to be doing on it.  Due to injury (from 6 years ago), combined with supporting my sons Desert Racing,  I've only been able to get in about 500-1000km per year. So regular oil changes will be easy. 

I'm hoping that in the not too distant future I will be able to increase my ride time... If it turns out that I can get back to doing multi day & long trips, the oil cooler is likely to go on.



-- Edited by Gadget964 on Monday 13th of April 2020 11:24:48 AM

Attachments
__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

smilesmilesmile The first Australian 350 is nearing completion... And the bike that it is going into is almost ready as well after having a significant facelift.



Attachments
__________________


Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

Looking at that shiny head reminded me I was thinking about head-work back in the mists of time, and the edge that marks the limit of the original bore could be eased to help gas flow from the outer edges of the combustion chamber since the 350 is significantly larger. However, this would reduce the compression ratio. Good for torque, bad for power I believe, so might have negligible gains unless a higher comp. piston is specified.

Discuss:

Looking forward to hearing your results Gadget. Good luck,
Simon.


__________________


Senior Member

Status: Offline
Posts: 370
Date:
Permalink  
 

Gadget964 wrote:

smilesmilesmile The first Australian 350 is nearing completion... And the bike that it is going into is almost ready as well after having a significant facelift.


 Well done Gadget I saw the sneak pics will look (and go) goodbiggrin



__________________


Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

Good news Mark, looking forward to seeing it finished smile

Another kit has just landed in Malta, hope Julian the owner will be posting up on here smile

So that's 4 or 5 up and running in the UK, 1 in Japan and 1 in Australia nearly finished and the new one in Malta, oh nearly forgot Brians.......C'mon Bri get on with it!!!

8 x TTR350's now exist in the world headbang.gif



-- Edited by ttr steve on Friday 1st of May 2020 04:54:28 PM

__________________

totallyttrs.com

 



Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

I only count 'em when they're running Steve
Mine #1, your's #2, Dan #3, Tiddler #4. Looks like Mark and Michael in a race for #5 unless Simon knows better...

__________________


Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

How is Dans? Dan where are you??



__________________

totallyttrs.com

 



Senior Member

Status: Offline
Posts: 239
Date:
Permalink  
 

Ahhh mines okay, I had it mot'd the day of the uk lockdown.

I did have problems with the cam positions and turned out the tensioner had snapped, replaced it and the cams are still slightly out sadly despite a fairly new cam chain.

I have been tidying the wiring etc for accessories etc as there was a drain somewhere as they were previously on the battery.

I Rigged up a oil cooler on it with a shorty pipe and just concerned that the pipes are close but I'll sort something as my friend Malcolm who used to be on here set his up well with that arrangement.

Next plan is to refit the raid stuff before grabbing an acerbis tank for the next big adventure.

As for the engine I love it, nice an torquey and the higher gears are much more useable. I wonder how it will cope at very high altitudes?...I can't wait to get out and try fine tuning it as I haven't had a chance since i got the Motad. Sadly I have been preoccupied with fiddling with the little c90 we use for stupid races

On a side note my girlfriend has brought a ttr raid (in bits) from a Malcolm, which will be her first project :)



Attachments
__________________

Thanks

Daniel Lee



Senior Member

Status: Offline
Posts: 122
Date:
Permalink  
 

Mine is still in the box. Wanna make a start on it, but I need an engineering Co to do my cass bore, so until I know I can get than done I'm in no hurry to dismantle the bike. I also know that when I do that it'll be the start of a likely not and bolt rebuild ! 



__________________


Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

Padowan wrote:

Mine is still in the box. Wanna make a start on it, but I need an engineering Co to do my cass bore, so until I know I can get than done I'm in no hurry to dismantle the bike. I also know that when I do that it'll be the start of a likely not and bolt rebuild ! 


 OMG forgot about you Simon, that makes 9 smilesmile 



__________________

totallyttrs.com

 



Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

Loving mine, the more miles the more smilessmilesmile



__________________

totallyttrs.com

 



Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

The mechanic doing the work in mine is apparently just waiting on the casing gaskets to arrive to complete the motor (he's had several parts delays due to Covid restrictions)

The interesting thing about this build, is that he told me yesterday that he can't wait to ride it. I've known him for almost 13 years and I've never heard him say that about anything..... Coming form an ex-factory Kawasaki rider and multiple Hattah Desert Race winner (up until Toby Price came along), that is something special.

These 350s are sparking a huge amount of interest.

__________________


Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

Good to hear, I have 2 left on the shelf at the moment 

https://totallyttrs.com/epages/699105d9-e4cc-4b32-b236-84e72cd67f84.sf/en_GB/?ObjectID=23761373

 



__________________

totallyttrs.com

 



Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

Just received a call... My motor is ready. But still 450km away. Covid restrictions starting to ease tomorrow, so I may be able to get it this weekend.

__________________


Super Guru

Status: Offline
Posts: 1255
Date:
Permalink  
 

Will be interesting to read the real road tests, my TTR feels like it has more torque than my WRR but the WRR has more HP...well that a seat of the pants feel. I'm guessing the 350cc TTR will have even more torque & will produce more HP down low than standard but being an over square bore / stroke it may not want to rev.

A drag race with a good standard TTR, 350 TTR & a good WRR would be nice as the seat of the pants feel can be way off. My standard TTR is still better than the WRR on hills, WRR needs to rev & gets wheelspin.

Now if someone could come up with EFI for the TTR to improve the fuel range & power !!!!!

Terry

__________________

TT-R250 & WR250R for dirty fun

Triumph Thruxton for the twisties

Triumph Scrambler for fun

 YOUTUBE channel https://www.youtube.com/channel/UCPSstOEnd2NSu0Va6kt2ySg



Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

The 350 still likes to rev, but you'll find you don't need to
Dynos are a few pages back in this thread, but Marks will be even better with free flowing pipes and a bigger carb. Low to mid range is MUCH more tractable, where the WR by all accounts you have to keep revving, as you say Terry. Top end is restricted by the airflow so I'm looking forward to #5's results too.

 

What is the idea behind your 600 headstock conversion Mark? Did I miss a post somewhere?



-- Edited by mossproof on Wednesday 13th of May 2020 09:42:28 AM

__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

How can I post big pictures? Mine just come up as thumbnails...Edit: figured it out.

So: My 350 is currently in my sons possession- and will be coming home to me on Saturday afternoon (very early Saturday morning in your time) I want to tidy a few things up on the casings before I fit it, so hopefully Sunday afternoon I will be right to crank it over.


TTR600 front end: Not sure if I mentioned previously, but my son now owns my old TTR250, but has a DRZ400 front end on it... When I used to do desert rides on it, placement of the front wheel when riding was always carefully (and quickly) planned, with the way he has it set up now, it just doesn't matter- hit whoops as hard and awkwardly as you like... just keep the throttle on..... That's what I want to achieve with the 600 front end. They are a bit beefier, so my suspension tuner will be able to dial them in better than he could the standard TTR forks (even though mine had gold valves). One of the things that I was especially after was having more adjustability (compression and rebound) than the 250 could offer... One of the down sides of working with (and riding) my sons race bikes, is that we have figured out that an extra click +/- can make a difference when riding on different terrains. Many years ago ignorance was bliss- It always felt "Pretty good" because I didn't know any better.

Lectron carbs are not being very useful at the moment. My plan for now is to use the original carb to fire the bike up, but I have an RMZ250 FCR that I'm looking to fit if I can. It may be physically too big, but I won't know until I get my motor back.

 

20190802_130451.jpg



-- Edited by Gadget964 on Thursday 14th of May 2020 08:14:39 AM



-- Edited by Gadget964 on Thursday 14th of May 2020 08:19:02 AM



-- Edited by Gadget964 on Thursday 14th of May 2020 08:27:30 AM

Attachments
__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

So I promised you all something different with this build:


Here we go:





My 1996 TTR250 when I bought it.

3.jpg

 

 

 

 

Photo taken today; awaiting the 350 motor.

96091634_1162212077492032_3106071785271984128_n.jpg

 

BRING ON THE WEEKEND



Attachments
__________________


Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

That'll confuse everyone. TT350 with estart. They'll ask why I went to all the bother if the factory already did it!

I've just fitted a Mikuni pumper onto an xt225 Serow for a customer. That's another option, if it would fit - quite a bulky carb.

Is there a weight penalty with the 600 forks? Looks lovely by the waysmile



-- Edited by mossproof on Thursday 14th of May 2020 09:32:34 AM

__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

Didn't check the weights.

__________________


Senior Member

Status: Offline
Posts: 370
Date:
Permalink  
 

Looks great Gadget, good looking machine. TT350 with e start and rear disc brake!! And a single carb I'm still fighting my dual carb setup on my TT trying to get it to work.

BTW the FCR won't fit the TTR I've tried with an FCR32 , they are just plain too big, there is hardly any room, starter is in the way and would have to go.
MikuniOz.com do a MikuniTM33 pumper in a kit for the TTR250 (so u know it fits) and includes throttle cables and quick pull throttle.


__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

I had my doubts about the fcr fitting, but without having the motor, it's hard to measure anything (the original carb is with the motor, so I couldn't even compare them).

__________________


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

Hello all,
I keep track of this topic and the great effort and work for the 350 kit. I would like to see a Dyno graph at some point with a bigger carb and free exhaust pipe. I believe the gains will be significant.
As I saw the discussion on another carb to fit, I would like to say that I have already installed a Dellorto PHF 34mm with pump and have the jetting adjusted. It fits perfectly, the only thing needed was an aluminum adaptor I had made for the airbox collar. The gains especially from mid to top are clearly noticeable.
Steve, Brian and all, keep up and stay safe!

__________________


Super Guru

Status: Offline
Posts: 8056
Date:
Permalink  
 

Hi Christos and good to see your first post to the forum.

Thanks for the contribution and your good wishes! 

Lockdown has eased slightly in England and I have been out on the road bikes and the TTR325 will be next for an outing biggrin

Brian



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ! 
 

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 



Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

Hi Christos

Thanks for the post, remember we all like a photo smile



__________________

totallyttrs.com

 



Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

Don't mean to sound grumpy fellas, but can we keep the thread for 350 - specific stuff. It's already a long trawl without general bike pics. Smart bikes and lovely sunsets though they are, "Show us your bike" might be a better spot?
Christos - a pic of your carb modification would be perfectly relevant here

__________________


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

IMG_20200515_183847.jpgMy apologies, here it is:



Attachments
__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

Turns out that the Mikuni TM33-8012 Pumper carb that fits the TTR is 'in stock' in Australia, and $471 delivered.... so I ordered one.

I had heard that the Mikuni carbs were a bugger to tune, so was trying to avoid them. But at that price, including throttle and cables, for a carb that will fit without having to make adaptors, I'll give it a go.

__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

My motor made it home about an hour ago. I'd forgotten how rough the paintwork was on the head and cases- I'll do a bit of a tidy up tomorrow, and should get it fitted. Not sure about started, but fitted at least.

Even if I do get it running, I can't ride it until a front wheel spacer arrives..... There's always something.



-- Edited by Gadget964 on Saturday 16th of May 2020 01:41:48 PM

__________________


Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

mossproof wrote:

Don't mean to sound grumpy fellas, but can we keep the thread for 350 - specific stuff. It's already a long trawl without general bike pics. Smart bikes and lovely sunsets though they are, "Show us your bike" might be a better spot?
Christos - a pic of your carb modification would be perfectly relevant here


 Sure Bri can tidy up, as you are right, it is going a bit of piste!



__________________

totallyttrs.com

 



Veteran Member

Status: Offline
Posts: 32
Date:
Permalink  
 

just a quick question as it seems you use the original head what is the situation with the head shape and what is the new compression ratio sorry thats two questions


john

__________________


Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

Yup John, same head. As I mentioned in response to Gadget's pic above, the lip at the limit of the 250 bore could maybe do with radiussing a bit to ease the gas flow, but the custom pistons were specced with stock compression ratio, Wossner did the maths off the spec of their standard replacement piston. 10.2:1 IIRC, but don't quote me - it's a long time ago now since I last thought about it! Removing material from the head would thus reduce the CR below stock. Possibly better torque? But I don't think it's necessary.

Gadget the suspense is killing me!

Christos thanks for the carb pic. Presume the throttle cable clears the frame above ok. I think the Mikuni may have clearance issues according to the info on the Aus website. It's all a bit tight in there!

__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

I'm super keen too. Hopefully today.

The head work was pretty much only intake and exhaust. Valve seats redone.



__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

IT LIVES. Fired straight up.


__________________


Super Guru

Status: Offline
Posts: 8056
Date:
Permalink  
 

biggrinbiggrinbiggrinbiggrinbiggrinbiggrinbiggrin



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ! 
 

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 



Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

First Australian TTR350.

 

20200517_175349.jpg



Attachments
__________________


Super Guru

Status: Offline
Posts: 8056
Date:
Permalink  
 

What a cracking bike - looks great! Loving the vintage look biggrinbiggrinwink



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ! 
 

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 



Super Guru

Status: Offline
Posts: 1017
Date:
Permalink  
 

Number five is alive! Good work Mark.

__________________


Senior Member

Status: Offline
Posts: 370
Date:
Permalink  
 

Looks great be interested in the ride report

__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

Waiting on a few parts. Pivot pegz and Speedo drive are the main bits.
Speedo was posted 2 weeks ago, in Australia, and still hasn't arrived. Post has been swamped over here apparently, meaning huge delays.

__________________


Super Guru

Status: Offline
Posts: 2298
Date:
Permalink  
 

I must admit I am confused???? The bike looks awesome, but its a TT350, where is the TTR350? Or did you put the TTR350 engine in the TT350 frame?

Or have you managed to fit the forks/tank/seat and mudguards from the TT350 to the TTR frameconfuseconfuse



-- Edited by ttr steve on Sunday 17th of May 2020 11:55:31 PM

__________________

totallyttrs.com

 



Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

Good. Happy that people are confused already.

 

Just to summarise:

1996 TTR250 => 

Fitted with:

  • Totally TTRs 350 big bore kit
  • TTR600 Forks and triple clamp
  • TT250/350 tank, shrouds, race plates, and headlight
  • TTR250 seat modified to suit tank and shrouds
  • YZ rear guard from the late 80's


__________________


Newbie

Status: Offline
Posts: 3
Date:
Permalink  
 

Bike looks great! Love the concept.

When and where is your first ride?



__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

My foot pegs arrived today, just waiting on front wheel spacer/speedo drive before I can get it mobile. Hopefully in the next few days. With a bit of luck I will have it registered before the Queens Birthday weekend and head up to the Sunset Desert... My mechaninic is keen to see how it feels as well.



-- Edited by Gadget964 on Monday 18th of May 2020 01:06:32 PM

__________________


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

Yes, no problem with the throttle cable...



__________________


Veteran Member

Status: Offline
Posts: 61
Date:
Permalink  
 

www.facebook.com/groups/467237210053657/permalink/2966397470137606/

__________________
«First  <  15 6 7 8  >  Last»  | Page of 8  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard