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

dfaz · Veteran Member

new member

dfaz · Veteran Member

Hi my name is Dave, recently purchased a 2004 ttr 250.I have allready carried out a few mods airbox snorkel and air filter,she breaths much better now,im about to carry out exhaust mods and rejet,if anyone is interested I have found a supplier in the uk for any jets you require they are about 4 to 5 pounds each i'll keep you updated and post some picks when I get time.

Cubber · Super Guru

Hello and welcome, dfaz. smile

Quick work on sorting the TTR.

Who/where is the carb. jet supplier. Is he local to you in the NW?

Let us know what you've done and what you propose doing - it adds interest for the records and for the others to see.

It's also cheaper if you do it and tell us if it doesn't work. biggrin

Martyn

TTRfan · Super Guru

Welcome Dave and, as Martyn says, looking forward to hearing more about your mods and seeing some pics wink

Brian

dfaz · Veteran Member

I took the bike out for the first time between christmas and new year (bloody freezing)but found the bike realy lathargic with no punch I modified the air inlet cutting the snorkel down both sides and fitted the K and N filter what a difference that made,the bike revs much more freely and is altogether more lively.She still lacks a bit of punch so today I have cut the exhaust and removed the restrictor, I will order the jets tomorrow the jets are from M C MOTOCARB they stock jets for Harley Davidson which are aparently Mikuni they seem to have a full range even half sizes.I have original 50 idle and 147 main ,when I checked the plug after the first mods it was running very lean so I'm going for 52.5 pilot and140 small round main I'll keep you informed and thanks for the welcome. Cheers Dave.

dfaz · Veteran Member

Woops forgot the telephone no of Motocarb its 0151 2384170.

dan-reeves · Veteran Member

Hi
Can you give me a brief description on how to remove the restrictor from exhaust please?
as i wouldn't mind doing this to my 03 TTR
Thanks
Dan

dan-reeves · Veteran Member

Yes thats brilliant i will give it a go on the weekend,
Thanks :)
Dan

dfaz · Veteran Member

Ok just to add to that I spoke to the guy at MOTOCARB today they are based in corby near Liverpool.I told him the part nos he was very knowledgeable and helpfull all jets in stock the two jets inc post and packing came to £9.90 they were sent today should be here tomorrow,he keeps high stock levels and is only short when Mikuni cant keep up with demand so if you do need them and quick he sounds perfect i'll let you know how I get on with the tuning,I have ordered a new motad silencer( well cant go halfway can I) so hopefully have it all back together this weekend should be interesting.

TTRfan · Super Guru

dfaz wrote:
I have ordered a new motad silencer( well cant go halfway can I) so hopefully have it all back together this weekend should be interesting.

You certainly move fast Dave biggrin

The silencer should be delivered tomorrow. Don't forget to follow Andy's instructions when fitting it and use some exhaust paste where the silencer meets the header pipe as it is a metal to metal joint. Took me a couple of tries to get it gas tight but well worth the effort wink

Brian

TTRfan · Super Guru

dfaz wrote:
a) I do have one problem if anyone can advise me ,the drain on the carb is seized solid I have left it soaking in oil but the head is chewed up from someone previously trying so any advice welcome.
b) Brian you mention instructions for installing the exhaust I fear my wife has recycled it along with the box so if you have any you could post on the site would be appreciated.

Hi Dave

a) Once the drain screw head is chewed you are basically b*lloxed! You need to drill and use a screw extractor to get out the old screw. Done quite a few in my time both for myself and some mates. It is always a bit worying that you might damage the float bowl but haven't done so yet - touch wood!

It is always a good idea to loosen and re-tighten the drain screw occasionally to make sure it isn't seized. Otherwise, you can bet your boots you will find the problem when out on the lanes and you have drowned the TTR and need to drain the carb cry

New ones are part number 14T-14323-00-00. Martin at MotoWard will sort you out wink

b) Exhaust (good isn't it biggrin ) fitting.

Sorry - I didn't mean to suggest there was a sheet of instructions. I was quoting from Andy's ad here - http://www.joatmoa.co.uk/ttr250/exhaust.htm where he says

"*They must be fitted using an exhaust paste on the joint with the front pipe."

Brian

truslack · Veteran Member

dfaz wrote:
original 50 idle and 147 main ,when I checked the plug after the first mods it was running very lean so I'm going for 52.5 pilot and140 small round main

Is that a typo, or are you going down on size with the main jet?

Mark

dfaz · Veteran Member

The jet sizes can be a bit confusing and from what i can gather the tekei carb jets are measured in .mm ie 1.47mm but the Mikuni jets are measured in flow rate and size wise the 140 mikuni is aprox 1.50 mm I hope ive got that right i'm sure someone will correct me if i'm wrong.I had the same thought and had to read through many pages on thumpertalk before it actually made sense espescially when other countries have diferent jets fitted as standard (BTW the idle jets are identical its just the mains which are different).
The exhaust arived today its half the size of the original and lighter,the jets also arived but unfortunately I wasn't available to sign for them so will pick them up tomorrow going to be busy Friday night thats for sure.
I do have one problem if anyone can advise me ,the drain on the carb is seized solid I have left it soaking in oil but the head is chewed up from someone previously trying so any advice welcome.
Brian you mention instructions for installing the exhaust I fear my wife has recycled it along with the box so if you have any you could post on the site would be appreciated.

Cheers Dave.

dfaz · Veteran Member

Thats a releife thought the wife was being a bit overeficient lol.I'll have another go at the drain screw tomorrow thanks again.
Dave.

dfaz · Veteran Member

Fitted the exhaust tonight first bit of spare time i've had, but as you predicted brian drain screw is bloxd! Ihave included a couple of pics.

dfaz · Veteran Member

Just to add fitted the jets in the carb yestserday the pilot jet was slightly longer ,same length going into the carb body slighly longer on the outside if that makes sense.the main jet screwed in most of the way with my fingers but the last couple of threads were very tight, I think the thread pitch is slightly different it went in ok just a bit tight.I will let you know how I get on I am waiting for a drain screw for the carb, had to drill it out new one should be here Wednesday as it was out of stock.

Dave.

dfaz · Veteran Member

ok got the drain screw for the carb finally so fitted and filled her up fliked the throttle a couple of times no choke and she fired up sounds completely different with the new motad zorst,it was pi@$ing it down has been all day but had to try it,idle screw turned out 2 turns tick over is smooth bike is much more responsive and actually lifts the front wheel if you catch it right gearing is still std , i'll be interested to see how other people are finding gearing changes 13 tooth front seems good but stressfull on chains any sugestions.

dfaz · Veteran Member

Too good to be true carbourettor is leaking from seals thought the originals were ok but obviosly not .more parts required.

TTRfan · Super Guru

dfaz wrote:
Too good to be true carbourettor is leaking from seals thought the originals were ok but obviosly not .more parts required.

Bad luck!

See http://ttr250.activeboard.com/t47592544/carb-rebuild-advice/ and scroll down a bit.

I think I say that experience has taught me to replace the float bowl gasket if it looks at all suspect else its a double strip down job if it leaks after fettling it cry

Easy for me I guess coz I keep a small supply of gaskets, O rings, diaphragms and carb screws on the shelf for such eventualities.

Brian

dfaz · Veteran Member

finally fitted the new carbourettor seals,having been caught out the first time I decided to fill the carb up with fuel before I fit it,sure enogh it leaked,on inspection it was leaking from the base where the fuel pump diaphragm and small 'o' rings were.I removed the base everything looked normal no dirt or bits out of place so retightened, tried again and it leaked,so this time I took the small plate and rubbed it on some wet and dry on a flat surfacein a circular motion,then I did the same with the base of the carb using the wet and dry wraped in a piece of carbon fibre to keep it flat,when the base looked polished I cleaned it and reasembled the carb, thankfully fuel tight so re fitted,' so its worthwile testing before fitting'.

dfaz · Veteran Member

Took the bike out this afternoon two quick flicks on the throttle and bike springs into life it needs a minute to tick over before you can rev the bike without it stuttering,I have to admit the bike is completely different it revs more freely, it will lift in first on the throttle,there are no flat spots, the bike is far more responsive and punchy.overall the mods have transformed the bike and for a couple of hundred pounds has been well worth the expense.I still feel the gearing is too high so thats the next project but if you have a ttr and wondering if its worth carrying out a few mods I can only say Go for it you will be supprised at the results.

Dave