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Post Info TOPIC: What Jets are you running?
Moo


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What Jets are you running?
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Thought it would be an interesting thread for everyone to post what Jets they are running along with any mods, exhausts and altitudes they are using.

Mainly because there still seems to be a lot of different standard jets the TTRs run and it's unclear why?

I've just fully rebuilt my bluey with the all balls kit, which uses the jetting 137 Main and 50 Pilot with the needle in the middle.

The bike is running standard, full airbox with snorkel and a motad exhaust, which i believe was designed to run without change. Altitude around Northampton is around 50m

The bike now doesn't run happy at all. If you crack the throttle open quick is hesitates upto 1/4 throttle and dies. If you slowly open it, it will rev up through the range.

Previous to the rebuild I was running it with standard Raid jetting, 145 Main, 48 Pilot, V05 Nozzle and it ran great. Probably slightly rich,as it popped on the overrun.

Now I know both Steve Brian run 137 Main and 50 Pilot. Steve on an OE and Brian on his 325. I presume both are using Motads? With an altitude that won't be too far off mine. Why is mine unhappy with this jetting?

Do you think it's running too rich off the pilot jet now? As when the throttles opened, the accelerator squirts petrol in.

Standard jettings I've seen so far...

 

OE 142/48

US Bluey 137/50

Alternate US Bluey 137/52

Raid 145/48

UK Bluey 147/50

Also two different nozzles.

The old and short V05 or similar new V00 

The newer longer V95G0



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Malcolm, Northamptonshire. West Anglia TRF 1996 TTR 250 Raid



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My 1994 OE spec:
137 main/52 pilot, needle in centre. Think it has V05 nozzle, can't remember for sure.
No snorkel, Twin Air filter, FMF pipe with effective home built baffle. No other mods.
Runs really well, starts easily hot, cold or recovering from upside down moment, would idle cleanly all day.
Just across the county border in Warwickshire, so altitude same as you.
Sounds rich off the pilot to me, but there are smarter guys on here!
RichR.

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Moo


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Yeah I think it's rich on the pilot too, matches Jarrahs advice of..."If it bogs down when you first roll on the throttle (eg. (1/4) ) then it suggests that your pilot jet is too big"

So might try it at 137/48 see what happens..


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Malcolm, Northamptonshire. West Anglia TRF 1996 TTR 250 Raid



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Keep us posted please, I have sold quite a few of the kits lately and always interested if there are any niggles. I had to sort the rubber seal on the  Air screw, did you change that, for the one I added to the kit?

It sounds like a blocked jet, did any crud/ water get in there when doing the work?

If you take the side of the air box and see if it runs any better, meaning the running rich would be confirmed.

What is the standard position of the needle for a bluey?? ( Bri) Maybe put it back to that? as it is now running the US spec jets.

You should not have to do any adjustments with the old V05 if you have not changed anything. If you fitted the newer and longer V95G0 then you would need to change the float setting to accommodate this.

Hope some of that helps, I am no carb expertcry



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Good idea for a database Malcolm.

For the record:

Thumper 325 bigbore OE with Motad exhaust, standard header, larger snorkel fitted to airbox, Twinair filter. Running 48/140 with V05 and needle clip 1 notch up from centre (leaner)
Altitude 0-150m but ran fine at 1500m in Pyrenees. Putting out 27hp at back wheel. Starts well on button but I struggle to get it going on the kicker when cold - maybe I should try bigger pilot and smaller main to compensate?

Standard 250 Open Enduro with standard exhaust and airbox. Twinair filter. Running 50/147 jets, V05 with needle in the middle.

Would be good to know what people are running successfully with different exhaust setups , maybe make it a sticky for reference...



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I am happy to put together the replies and make it available as a sticky thread Simon. Let's see what responses we get first!

I hesitate to give advice on carb setups as, like Steve, I don't feel that I have the expertise required.

I tend to stick with standard jets and settings and run a bog-standard airbox and Motad exhaust. I don't have any experience with carb settings for opened-up airboxes and varying altitudes - not an issue here in Devon, UK smile

What continues to surprise me is the odd combinations of jets that I find in the carbs I have rebuilt over the years. 

Just looking back over recent rebuilds they included 137/50, 142/50, 147/50, and 147/48. Unfortunately I didn't make a note of the nozzles used with these jettings no

But what I can say is that I road tested all of these carbs and they all worked just fine with no bogging, etc.

So I remain baffled by the whole TTR carb jetting business - sorry guys disbelief

Brian

PS I really miss Jarrah's input on carb issues.......



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Mine has 50/145 jets, V05 in the centro. Hiflo air filter, snorkel is on, CRF 250R standard exost muffler. It was running fine.
However, now it started hesitating at high rpm when driving. It starts cold and hot and revs from min to max rpm without issues.
Only the problem when driving ant high/max rpm. would could be the problem?

Other TTRs that I had were using 48/142, 48/147

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learning to ride on 1993 TTR 250

Ex 1997 and 1998 Honda XR 250

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