7 replies to this topic

[Replicant]

Thanks for all your comments.

 

If the 2nd upload works then you can see there doesn't seem to be that much ovalling of the tube and as thought the butterfly was giving a bright spot that made the needle look worn.

 

I'll clean up the jets and airways as Studley suggests and hope that works cos not sure where to go after that

 

@MipeTDM    It doesnt need choke at the moment and the spitting gets better once warm but it still runs bad up to 5 thou. Not sure it's lean, the plugs are dark and sooty even after a short run. It def could be using more fuel than usual but havent had it back on the road long enough to tell.

 

@Studley  How did the fuel get into the oil?

and  'Cut the tangs off the inlet rubbers and you can position the clamps to suit. ;)'  def inetly gonna give that a try

 

 

 

 

it's the 1999 onwards TDM 850 that has the harder wearing carbs.  I'd get a magnifying glass and look at those needles carefully.

 

 

Dunno if it's the brighter spot on the butterfly but that needle looks to be a funny shape, I'm sure the carbs had the same issues till MK2a.

 

 

Just out of interest, what mileage/kilometers are we talking about, that these tubes/needles wear out? (as I also have a MK2 from 1997).

BTW these needles do indeed show a quite apparent discrete jump in thickness at one place.

 

 

According to Factory Pro, oem toobs can wear after 5000 miles.

 

Might be worth checking the engine oil level and also have a smell (lick) of it to see if there's any petrol in there.  Sidey blew his carbs off the mk2 after he got fuel leaking into the engine.  Lucky he didn't damage the engine.

 

Cut the tangs off the inlet rubbers and you can position the clamps to suit.

 

Not sure it's the emulsion toobs, worn ones tend to result in a wiff of fuel and poor economy.  More likely to be gummed up jets/airways and/or pilot screw settings need adjusting and carbs balancing.  Might help if you add some Redex to the fuel, it deffo helps if you're not riding the bike all year round.

 

 

I only now noticed the video, it was still early in the morning last time I looked at this topic

 

The spitting I also associate with a lean condition, more especially an intake air leak. Could indeed be the carb boots (which you replaced): check if the clamps are correctly tightened down, after warnming up the engine.

But also look at the air lines to the fuel pump, idle circuit/choke to name a few things. You could spray e.g. some brake cleaner or deodorant at these parts and see if it is sucked into the engine via any leak.

Do you use the choke when the engine's cold? Does this spitting remain when the engine is warm?

 

Edit:

Sometimes if the jets are a bit clogged but not fully (yours are definitely not fully clogged, if at all, as it is still idling on all cylinders), these can clear when new fuel is passing by after the 1st ride (and maybe some fresh fuel).

 

 

Can't see anything from the photo, apart from some marks on the needle - need to look at the emulsion tubes from directly above for ovalling. Spitting could also be caused by very tight valve clearances 

 

https://youtu.be/yvB9LZ90Un8

 

Hi,

 

as the subject line suggests - I'm thinking Emulsion tubes but happy if anybody else wants to throw their two-penneth in and dissuade me as I didn't enjoy doing it last time and now i'm older and less tolerent,  so save me!

 

Background is it's a 1997, was laid up for 6 months but turned over every so often. Took it out, and it was running as rough as a badgers arse in the low revs, after 5 it would fly. However, the more I rode it the worse it got. Took it apart, started it up and it blew the carbs off the rubbers (similar spits in the first 10 secs of vid!). Changed the rubbers (btw if anyone has got some choice words as how to get at the screws to tighten up the carb to inlet retainer, I'm all ears). Also, replaced the airbox rubbers as per instuctions by dapleb of this parish (thank you, nice tip). The spitting is a lot worse when it's cold.

 

So this is a MkII and silly me I thought Yam had cleared this issue up for the later model, Emulsion tubes, that is.

 

Any thoughts welcome

 

cheers  IMG_20200623_185136 (3).jpg   98.77KB   0 downloads

 

 IMG_20200623_184907 (2).jpg   88.62KB   0 downloads

Edited by Replicant, 23 June 2020 - 08:16 pm.

[dablik]

Thought it was the later model mk2 had non replaceable mulsions !! could be wrong, i believe someone pressed em out once upon a time, it's on the site somewhere, they do look worn but ya better wait for a better eye than mine as i'm orf to spec savers in the morning..

[wicklamulla]

it's the 1999 onwards TDM 850 that has the harder wearing carbs.  I'd get a magnifying glass and look at those needles carefully.

[Snowbird]

Dunno if it's the brighter spot on the butterfly but that needle looks to be a funny shape, I'm sure the carbs had the same issues till MK2a.

[MipeTDM]

Just out of interest, what mileage/kilometers are we talking about, that these tubes/needles wear out? (as I also have a MK2 from 1997).

BTW these needles do indeed show a quite apparent discrete jump in thickness at one place.

Edited by MipeTDM, 21 June 2020 - 08:21 am.

[Studley Ramrod]

According to Factory Pro, oem toobs can wear after 5000 miles.

 

Might be worth checking the engine oil level and also have a smell (lick) of it to see if there's any petrol in there.  Sidey blew his carbs off the mk2 after he got fuel leaking into the engine.  Lucky he didn't damage the engine.

 

Cut the tangs off the inlet rubbers and you can position the clamps to suit.

 

Not sure it's the emulsion toobs, worn ones tend to result in a wiff of fuel and poor economy.  More likely to be gummed up jets/airways and/or pilot screw settings need adjusting and carbs balancing.  Might help if you add some Redex to the fuel, it deffo helps if you're not riding the bike all year round.

[MipeTDM]

I only now noticed the video, it was still early in the morning last time I looked at this topic

 

The spitting I also associate with a lean condition, more especially an intake air leak. Could indeed be the carb boots (which you replaced): check if the clamps are correctly tightened down, after warnming up the engine.

But also look at the air lines to the fuel pump, idle circuit/choke to name a few things. You could spray e.g. some brake cleaner or deodorant at these parts and see if it is sucked into the engine via any leak.

Do you use the choke when the engine's cold? Does this spitting remain when the engine is warm?

 

Edit:

Sometimes if the jets are a bit clogged but not fully (yours are definitely not fully clogged, if at all, as it is still idling on all cylinders), these can clear when new fuel is passing by after the 1st ride (and maybe some fresh fuel).

Edited by MipeTDM, 21 June 2020 - 09:58 am.

[dandywarhol]

Can't see anything from the photo, apart from some marks on the needle - need to look at the emulsion tubes from directly above for ovalling. Spitting could also be caused by very tight valve clearances