21 replies to this topic

[Jez]

For a while now the old girl has been exploding like a shotgun on start up. Recently she has been hydraulic locking (is this correct terminology?) when left for 48 hours.

Looks like time to change the float valves.

My query is that if I change these then I will have to reset the floats - no?

I have searched hereabouts and found lots of info on MK1s and some mention of MK2s but nothing solid other than fuel level settings. It seems that 13mm is a good float height setting but measured where? and is this figure specified somewhere or is it just someone's experience?

The job will have to be done so I may just resort to measuring the float heights before dissassembly and setting them the same upon reassembly.

Has anyone any hints, tips, advice, warnings or insane ramblings on the subject of changing MK2 float needles?

[jht]

assume u turning fuel tap off when bike left overnight or longer??

You may want to check tap aint leaking by before you fo sort out new float valves etc

when i did mine I could find no solid basis for the 13mm float height measurement other than postings here and (i think) a comment on the factory pro site.
I did mine at 13mm initialy, then when checked it as per Yam method it was around 4mm out...

It may provide you with a suitable starting point but tbh i'd go with fuel height as specified by Yam,
dead easy to do if you got the cards off the bike, & the only 'special' tool you need is some clear windscreen wiper tubing form the monkey shop (Hellfords) tho I can't remember the I/D you need, have to look in garage later.....

Edited by jht, 08 October 2007 - 07:01 pm.

[dapleb]

Weeman posted somewhere how to set the level on mkII's. There is a marking somewhere on the mkII carb body that is the mark to measure from. The levels specified on Factory Pro site are for mkI only (which doesnt have the same carb marking)......being a US company, thats the only TDM they know.

[Jez]

Cheers for that guys. Okey dokey. What I will do once I get the parts is:

Measure fuel levels on bike.
Remove carbs and measure float heights.
Change float valves.
Reset float heights to what they were.
Check fuel level.
Refit carbs.
Bin the 'push' cable as it keeps coming off the carb anyway.

(In the meantime I will contact the wee one)

Is there a tendency to destroy the float chamber gasket? Unless I am missing something I cannot see one on the parts list - mind you it is a parts list for a MK2a.

Any other thoughts on what I should do and/or look out for whilst inside the carbies?

Edited by Jez, 09 October 2007 - 06:55 pm.

[jht]

Cheers for that guys. Okey dokey. What I will do once I get the parts is:

Measure fuel levels on bike.
Why measure on bike then check off bike?? Whip carbs off, check fuel height & float height on bench (interested to see ya figures there!) fit ya stuff, set float height if you wish to then check fuel height.
What would be more benefitial is set fuel height THEN see what your float height isRemove carbs and measure float heights.
Change float valves.
Reset float heights to what they were.
Check fuel level.
Refit carbs.
Bin the 'push' cable as it keeps coming off the carb anyway.

(In the meantime I will contact the wee one)

Is there a tendency to destroy the float chamber gasket? Nope not really Unless I am missing something I cannot see one on the parts list - mind you it is a parts list for a MK2a.

Any other thoughts on what I should do and/or look out for whilst inside the carbies? Toobs, tho thought you'd done them, past that good clean out with carb cleaner and a blow thru...

[stormy]

Hang on before you start pulling them lickle bastids apart!!!!

I've just gone through this very expensive episode, because of the exact same symptoms.

I would first of all check that the vaccum line from the cylinder inlet stub to the pump isn't wet.
I replaced all the floats, needle valves, air mixture screws, all to no effect.

The cause of the locking?

Bloody diaphragm in the fuel pump had a tiny hole in it, which meant when the engine was stopped, the fuel was leaking from the tank through the pump and along the vaccum line to the cylinder, and filling the cylinder up.

Worth checking before you spend lots and lots of dosh and time.

Easy to check it.

Disconnect the fuel lines from the carbs completley, so that there is no way fuel can run from the carbs to the cylinders.
Drain the carbs.
Reconnect the (full if possible) fuel tank to the fuel pump only, but DO NOT connect the pump to the carbs.
Leave overnight if possible.
If it still locks solid the next time you try to spin the motor on the starter, then thats your problem.

Mike

[jht]

D'oh.. i'd forgotten about ur fuel pump aggro Stormy

[stormy]

D'oh.. i'd forgotten about ur fuel pump aggro Stormy

Tis all sorted now, and she runs lovely.

Just need to fit me newly painted wheels, and she'll be done for this year. Over the winter I'll get the plastics repainted to freshen up their appearance.

and then put the original engine back in.

seems I may be busy this winter!

[Jez]

That sure is fortuitous timing, Mike. Nice one .

I discussed my 'locking' prob with someone who should know more about these things than me. He said that if the floats were high or the valves were leaking the engine would slow and eventually die at idle - which mine does not. Also the plugs are a luvverly brown colour.

He suggested I turn off the tap at night but I am bound to forget to turn it on and, anyway, I didn't need to in the past.

I went to the local Yam thief dealer anyway and was horrified that the valve sets are £29 + vat each with no option to return them if they are not required .

I did order air box rubbers and when they come in I will look at the pump diaphram and maybe get one anyway.

I will report back when I can (there is no emoticon for 'fingers crossed').

Can we have some pics of yer new wheels when they are on please.

Edited by Jez, 12 October 2007 - 03:44 pm.

[stormy]

That sure is fortuitous timing, Mike. Nice one .

piccies of stripped down fuel pump.

holed diaphragm is where the fuel tracked back into the engine (pen shown only for clarity before some wiseass says anything!!)

Can we have some pics of yer new wheels when they are on please.

Imagine some stock black/grey wheels ...... ok,


now imagine them silver!!!!!






but yeh, sure, when I get them fitted.!

[Jez]

Thanks for they piccie Mike. I would be sooooo touched if I thought you stripped your fuel pump just so you could photo it for me .

Got all keen and trundled to my local Yam dealer today but they don't do service parts for the pump only a complete item (I didn't even ask how much that would cost). Were'd you get the diaphram from please, Mike?

[jht]

Dont Kedo do a replacement fer around £29...???

[Hartside Man]

piccies of stripped down fuel pump.

holed diaphragm is where the fuel tracked back into the engine (pen shown only for clarity before some wiseass says anything!!)

why did you poke a pen through it ?

[stormy]

Dont Kedo do a replacement fer around £29...???

yes they do, page 65 of their current catalogue.

Thanks for they piccie Mike. I would be sooooo touched if I thought you stripped your fuel pump just so you could photo it for me .Got all keen and trundled to my local Yam dealer today but they don't do service parts for the pump only a complete item (I didn't even ask how much that would cost). Were'd you get the diaphram from please, Mike?

I did take the old one apart so I could picture it for you!!! otherwise it would have gone straight in the bin ........doh!!!!!I didn't get a new diaphragm, I had another pump in my garage (attached to my TRX.....)

why did you poke a pen through it ?

seemed like a good thing to do at the time ................

[Jez]

yes they do, page 65 of their current catalogue.

Thanks for the info. Found a pump on page 65. it is now on order.

Be aware that Kedo make a minimum charge of 50 euro and that is not including postage.

I will let you know how it goes.

Edited by Jez, 20 October 2007 - 03:26 pm.

[stormy]

Thanks for the info. Found a pump on page 65. it is now on order.

Be aware that Kedo make a minimum chharge of 50 euro and that is not including postage.

I will let you know how it goes.

Shit....

I'm going to Hamburg next weekend, I could have picked it up for you and brought it back free. I go to Germany (Hamburg area) most weekends, so if it is small, I don't mind bringing it back. Open offer to you guys. (Just don't ask for a full exhaust system or a set of wheels, this is hand luggage only I'm talking about here!)

I went to a jobs fair about 3 weeks ago, and it was right next to the Kedo place. Nothing fancy to look at outside, but you peer through the windows, and they got a lot of stock, and some very nice examples of XT500s, SR500's, TRX's etc mounted on the walls.

And they do stuff for my Strom aswell, so nice to know these dudes!

Edited by stormy, 19 October 2007 - 05:23 pm.

[Jez]

Ah well. Thanks for the offer. Maybe next time .