10 replies to this topic

[Dazzo]

I hate Carbs, really really hate carbs.

Recently my TDM started to play up at low revs when the bike was warm. Know what I mean? Turn in at a junction, open the throttle and miss-miss-splutter then clear up and run clean. Obviously running rich thought I, but just to confirm I PM'd Mr Eccles to run my thoughts by him hoping he'd help. He suggested a few things I should try so at it I went, armed with my workshop manual, screwdrivers & allen keys.
I tried the following

1. Removed the carbs and cleaned them, no difference
2. Lowered the Dynojet needle a groove, worse
3. Raised the needle a groove, worse
4. Took out the dynojet kit and rebuilt to standard, no difference
5. Lowered the standard needle a groove, worse
6. Raised the standard needle a groove, much worse
7. Checked float height using method described in Haynes manual
8. Cursed and swore and nearly gassed myself in the garage, went in house and got drunk

Day 2

1. Altered the float height to 13mm using a method I picked up off the old forum (one was at 11, the other already at 13) picture attached courtesy of Dapleb I believe.  float_height.jpg   77.46KB   332 downloads
2. Rebuilt the carbs to Dynojet spec
3. Replaced O rings around the main jets just in case

There was also a leak from my thermostat housing that was dripping onto one of the plug caps but my feeling was this would cause it to miss right through the rev range if it was going to cause a problem. I repaired this at the same time.

Took the long way home from work yesterday to warm the bike up a bit more than normal and so far no miss in evidence , longer run tomorrow when I'm off work
Thanks Al for your help and advice throughout. I owe you one

[wicklamulla]

glad ya got her sorted big man, feckin fiddly job all that teking them fecks in and out.

[dapleb]

nice one Dazzo. In me pic, the "This edge of casting should be horizontal?" is a load of bollix, that casting means chuff all (apparently there IS some relevent casting on the MKII carbs!). Float height should be measured on the rectangular float (rather than the diamond one) as there is a few mm diff in height of the two floats!

Cheers
dapleb

[Jana]

Picture doesn't work when I click on it.
Here is the direct link: http://www.carpe-tdm...-1144949778.jpg

I am atempting to use this method. Has anyone else used it succesfully lately?

[dapleb]

Not lately but it worked fine fur me. Others prefer fuel height method.

Just make sure you measure to the correct float.

[LewisBlackburn]

you know I'm glad this threads been revived.

My thermostat housing was leaking the other day ! and that is exactly the problem I'm having at the moment.

Hmmmm


Lew

[Studley Ramrod]

Haaaaaaaa ! think we had a chat about yer green furry bits iirc Lew.

The dripping thermostat doesn't necessarily make the engine miss throughout the rev range. It's a lot less noticeable at higher revs/speed, probably due to the bike leaning left to right and also the effect of the wind prolly redirecting the drip.

Also, you might not even see it leaking until the engine's warmed up and the thermostat's open.

If it's not yer stat leaking, I have a funny feelin' it might be one o them cooling pipes connected to the carbs

I was movin' 'em about quite a bit trying to do the pilot screws and it were getting dark.

[Jana]

Trying to develop this method further:
Here it is, resonably level, really don't think it matters bacause float didn't seem to move if i tilted it a bit.





The tools



The thing on the left is 16mm above the meassuring point. So is the foam thing on the right. Ruler sits on both of them.
Using feeler gauge to meassure gap = 2mm



Another pic of the gap:



So 16mm - 2mm = 14mm

Float hight is 14mm?

Do you think this is a good way to do it?
Is 14mm ok for a MKII?

Apreciate some advice!

[LewisBlackburn]

Haaaaaaaa ! think we had a chat about yer green furry bits iirc Lew.

The dripping thermostat doesn't necessarily make the engine miss throughout the rev range. It's a lot less noticeable at higher revs/speed, probably due to the bike leaning left to right and also the effect of the wind prolly redirecting the drip.

Also, you might not even see it leaking until the engine's warmed up and the thermostat's open.

If it's not yer stat leaking, I have a funny feelin' it might be one o them cooling pipes connected to the carbs

I was movin' 'em about quite a bit trying to do the pilot screws and it were getting dark.

Well what happened was on Monday morning I started it and it was leaking coolant, quite heavily, so i went n got a bottle of water and stuck it in me top box and set off for work.

Ain't seen it leaking since, so more than likely not the problem

at the moment though I'm getting spluttering below 3K when accelerating

[Studley Ramrod]

Don't worry Lew, I have a plan ! and a pilot screw screwdriver, and a Haynes ! All we need is sunshine