Carburretor Guru required

[Rincewind]

I could do with a carburettor Guru trained in the Art of Mikuni !!!

My 87 DR 600 got progressivley bad at starting last week to the point on Saturday where it refused to fire at all.

I have stripped and cleaned out the carb (it was pretty bad) and have reinstalled it but it still refuses to fire, I've got a nice fat spark at the plugs and when it was running last week (when it eventually started of course) it ran like a rocket ticked over a treat too, ----Help.

I've been searching the web for some info on Mikuni carbs but can't get any info relative to the model carb that's fitted to my sikkle. Does any one know anyone in the AK area that does replacement or rebuild on these animals...

[FROSTY]

probably stating the odvious but are ya sure you cleaned it out propperly?
All the jets pulled out and thouroughly cleaned out.
Just another wee point--are ya sure the tank hasnt got some shite in it ??

[Paul in NZ]

Well....

Are you sure it's the carb? 87% of all carb faults are in the ignition system..

You bike needs...

1. Fuel
2. Air
3. Compression of 1 and 2 above
4. A spark to ignite 1, 2 and 3 at the correct time.

One of these is missing.

Things to check...

Is the carb getting a good supply of fuel?
Is the tank vent working OK (otherwise you get a vacuum and the bike dies)
Is the float OK?
Is the choke free and working properly?
If your bike has a 'prime' setting it possibly has a vacuum operated fuel tap which are the work of the devil and easily bunged up with crud. Remove and clean out.
Is the air cleaner clogged?

Hook everything up and try to start it up....

If it does not start, remove the plug straight away, is the plug 'wet' with unburnt fuel. If so, you are eith flooding, (too much fuel) or have an ignition problem (maybe timing)

Good luck.

[skidz]

How much shit is in your tank? If you only clean your carb and not the rest, you're gonna get the same prob.!!

[Rincewind]

Hi
No crap in the tank mate, I cleaned that out along with the fuel tap and filters, the bike had been standing for a long long time and I suspect that some one put petrol in from a gerry can to get it going because there is no sign of any rust inside the tank !!!

just seen a replacement carb on trade me for 120 bucks but I,m not sure of the model, my carb has no numbers on it at all (very helpfull) can't ask the guy any questions cause I aint an authenticated member, (they want money off me for nothing, I don't think so)
oh well, just ordered a manual for it from my local dealer, gonna be two weeks though before I can get my hands on the technical stuff to start looking for the problem.... Buggger :mad:

[Rincewind]

Thank you for the info, process of elimination started already, fuel supply to carb is exellent tank vent is free, spark plugs are very wet and smell of fuel after half a dozen kicks with no hint of a rumble from the engine. Nice fat ble spark from the plugs when they are outside the cylinder so I guess the problem is too much fuel, It's a bit of a mystery why this problem suddenly crept up on me though after weeks of normal (if you can call starting a big single normal) operating!!
I have owned three of these beasts and I swore after the first one that I would never have a kick starter again (should have stuck to my plan Ha Ha)

[Rincewind]

probably stating the odvious but are ya sure you cleaned it out propperly?
All the jets pulled out and thouroughly cleaned out.
Just another wee point--are ya sure the tank hasnt got some shite in it ??
you know even though I can't get the bugger started it 's comforting to know that someone else is applying the old grey matter towards finding a solution, they say a problem shared is a problem halved, should sort itself if I share it around a bit Ha Ha

Oh well looks like wifey's walkin to work for a bit, that'll keep the weight off her !!!!

[DingDong]

If the plugs are wet, and your getting a good spark you should get some response from it (back-fire?), I dont know your carb... sorry, but everyones already pointed out the obvious (float level is what Id check first after hearing the other info youve supplied)
Another possibility is the timing has been upset somehow... chain?, chain adjuster?, points?

Good luck :yes: