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Post Info TOPIC: Won't run at revs..


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Won't run at revs..
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Ok just went out for a blat and bike died on me... basically it will tick over but dies if I rev it....she won't even pull off.

I had a problem with her a few weeks ago that when I reved her I had a flat spot when I grabbed a fist full but I thought maybe previos owner had old fuel in it.... Any way I'm guessing crap in the carb???

My mates got a sonic cleaner so I guess maybe take it to him....and other thoughts??

D



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An easy first check is to loosen the petrol tank cap just in case the valve has corroded and got stuck thus not letting air in.

Otherwise, just make sure that you have petrol flowing into the carb. Put a rag under the carb, put out any naked flames or cigarettes, and open the drain valve on the float bowl to make sure petrol is getting into the carb.

If that works OK then you probably have the common problem caused by TTRs being laid up for a while, which is a blocked or partially blocked pilot jet. Sonic cleaning doesn't always work on them so be prepared to put a bit of copper wire through to clear any possible obstruction.

See here

If the carb hasn't been apart for a while you may need a new float bowl gasket as they flatten over time and it's annoying to put the carb and airbox back on only to find the gasket is leaking no

Brian



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KThanks again Brian....will do the checks you said then strip her down..
It did have this flat spot that seemed to solve itself so maybe the start of a blocked jet.... ?
I didn't realise how quick fuel goes off these days.... Shell say 3 to 4 weeks 😨.... I bought additive for mine from now on to save all this messing..
Dave



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Fairly well stripped...Brian how do you get the throttle cables off the carb???
Been messing but I can't seem to work it out...???
D

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Keep turning the locking nuts and the cables will free up and you will be able to slide them off the actuator smile



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Pete. South Somerset, England.



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Many thanks...its a learning curve for me so sorry for the daft questions d

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Main jet blocked as Brian suggested...too small to photograph. ..

This could be basket gunk??

20150721_175934.jpg



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Gasket...
Stupid spell check

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Defo worth a new gasket i'd say.

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Pete. South Somerset, England.



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20150721_175934.jpg

Make sure the drain valve will unscrew whilst you have the float bowl off Dave wink



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Sorry folks for all this daft questions but it's all new to me so they're gonna keep coming....is this normal or do I need a new diaphragm? ?20150722_142306.jpg20150722_142309.jpg



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The diaphragm looks OK with no tears but why did the PO need to use gasket goo confuse

PS Don't forget to put the spring in when you put it all back together - and, yes, be careful with the airline biggrin

PPS New one looks like this:

Diaphragm1.JPG

Diaphragm2.JPG

Diaphragm3.JPG

 



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Ok thanks Brian...shhh don't let my airline secret out...😨

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Ok nearly gott her together and I managed to strip this.... I was being so careful but the air box is a bit of a pig to line up the bolts.... crappy threads but ain't doing up now😕 any suggestions? 

Longer bolt with washer in air box?? A so took lots of pics but not quite sure of the breather routes?? 20150724_201813.jpg

 



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Yeah - they can be difficult to line up whilst trying to get the intake rubber to sit properly on the carb no

Is the nut turning in its slot or are the threads definitely stripped on it?

The nut will pull out of the side of its slot. Yamaha doesn't sell them separately but if its stripped then I probably have a good spare if you want one?

I have seen the box drilled to do what you suggest but it's easier to keep it standard.

Use a bit of copper grease on the others to keep them sweet wink



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To be honest I thought it was just straight into the plastic...maybe the nuts dislodged?
It was getting late and I was being hassled to finish up so I just packed up....
Have you got any photos of the breather runs ?
I took some but not very clear... also think the one way valves have been removed??? I don't know why people mess with stuff and don't put it back??
D



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Sideways view of the "nut" - not the best but you can see its square top and the slot in the airbox that it slides into:

Airbox captive nut.jpg

The pipes should look like this - one-way valves arrowed:

Carb pipesa.jpg

 

Trying to find pics of the routing. This is what they look like on the carb:

Removing_carb5.jpg

 

 



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20150720_173842.jpgThanks Brian thats really useful..
Ive got the route at the carb end just how/where they then go.... mine go into clear pipes so obviously messed with...They then goto the right of the cdi..?)



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20150720_173811.jpg



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The pipes leading upwards from the carb go straight up behind the shock and come out where you see them in the photo below:

Removing_carb4.jpg

 

Sorry I can't find any clearer photos.



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Mine are to the seat bolt post then two lines go into 2 clear pipes as my photo which also go under the seat with no valve??? Do the one way valve just dangle loose??? Can you buy the one way valves and or breathers?

I'm determined to get this bike how yammy designed it
Ta d



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The inside breather with one-way valve dangles down between the frame and crankcase as shown in photo below:

Breather pipe.jpg

The outside one is shown in the photo in my previous post. It clips to the emulsifier pipe although it isn't clipped on in that photo although it shows the clip on the breather pipe.

The one-way valves are available from Yamaha at £12.68 inc VAT.

If you want s/h, I have some spare pipes and one-way valves I think. Just let me know what you are missing.

Cheers

Brian



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Thanks Brian ill be in touch shortly..... don't mind s.h was thinking maybe change the lot to original....

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Thanks Brian ill be in touch shortly..... don't mind s.h was thinking maybe change the lot to original....

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20150727_162603.jpgOk why the bejusus can I get enough slack on this to get it back on????
I've not touched anything handle bar end....



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You could slacken off the other cable a bit Dave?

If that doesn't do it you are going to have to pop the covers off the throttle tube and check that the cables are all sitting properly in there.

Should get it looking a bit like this:

Removing_carb8.jpg



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Tried slacking it off fully.... already Brian ????
I'm gonna have a look if somethings come a miss tother end... (after a cup of tea) 😉
d

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Close up pic of the airbox nuts removed from their slots.

Airbox nuts.JPG



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Well thanks for all the advice and help😉
I've got her back together and she started great.... The throttles not returning so have ordered a cable oiler as the cables are dry and see if that helps.
A steep learning curve but really enjoyed the tinkering.
Thank goodness for this forum though!!
Ttr fan you're a star if I ever get a chance a beers coming your way.
👍
Dave

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Moo


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Tommy the cat wrote:

Well thanks for all the advice and help😉
I've got her back together and she started great.... The throttles not returning so have ordered a cable oiler as the cables are dry and see if that helps.
A steep learning curve but really enjoyed the tinkering.
Thank goodness for this forum though!!
Ttr fan you're a star if I ever get a chance a beers coming your way.
👍
Dave


 Watch out with the cable oiling, i think if they're teflon coated cables they're not supposed to be oiled, but can be cleaned through with WD40

 

Source: Venhill cable maintenance guide :D



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Moo is absolutely right about not oiling Teflon lined cables. I didn't know this until we started buying Venhill cables and read their instructions disbelief

Remember that cables are service parts, the same as chains and sprockets and should be replaced after a while. Not sure how long that might be though! I guess when the Teflon has worn through and I suppose the only way to tell that is when the clutch or throttle action starts to deteriorate.

I recall a post that said that a rich mixture can cause a TTR not to return to idle quickly..... Can't vouch for it though....

Brian



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