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Old 01-06-2019, 06:22 PM   #1
Orc
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600 monster issues

I'm hoping for some technical advice
I recently bought a 94 600 monster
The bike has recently been partially restored.
It was sat for a year inside and so far I have only managed to ride her the 12 miles back home .
She won't idle properly is hesitant and really down on power.
It seemed like she was running very rich with smoke coming out at idle.
So far I have

Replaced the old fuel
Replaced the plugs for standard champions
Cleaned and rebuilt the carbs ( but not the needle or emulsion tubes)
Check the resistance across both sides of the coils
And ran a compression test on the engine ( was well within specs)

I had her running after all this and still the problem remains and I then noticed what seems like oil leaking from the horizontal exhaust flange

I am at a loss to know where to go next
And any advice would be gratefully accepted
I just really want to be able to get out on her
Thanks
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Old 02-06-2019, 07:28 AM   #2
Nickj
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So the carbs are mostly rebuilt, and the float levels are set and good?
Check the carbs balance, can be a pain as the motor revs slowly and there are a lot of big pulses of pressure. I use one of those ball bearing in a tube system which works OK.
The CV diaphrams ought to be rechecked for and pin holes.

Does the smokey exhaust smell oily or fuelly? the Mk I nose is often a good guide to a rich mix or oil burning. With compression within specs you'd maybe lean towards the valve seals.

If it looks like oil it may well be, you should have had really a really sooty looking plug IF it's coming out of the motor unless it's just leaking from the valve seal and not dripping out of the exhaust valve seal.

Also check the valve opener and closer tolerances while you're at it. The 600's don't make massive power to start with so any loss (or gain) can be noticeable.
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Old 02-06-2019, 08:09 AM   #3
Orc
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Thanks nickj
it smells like fuel, i have checked the diaphragms for holes and they seem ok. I can clean the plugs run it for a minute or so and they are black and sooty again.
I will borrow a carb balancer and give that a go
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Old 02-06-2019, 08:50 AM   #4
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Just a thought: does it have a (Clean) air filter and lid fitted? Could it have been jetted up by previous owner to suit no filter and straight through cans?
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Old 02-06-2019, 09:34 AM   #5
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Hi darkness
It has a standard air box + filter and exhaust system
I guess I could try and get hold of a set of standard jets
Cheers
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Old 02-06-2019, 12:43 PM   #6
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Or just check what they are to start with?

Make sure they aren’t off a 750 or 900.

http://bradthebikeboy.blogspot.com/2...d-without.html
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Old 02-06-2019, 12:49 PM   #7
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Something else to look at are the carb vent pipes to the little plastic pods on either side of the frame.

http://www.ukmonster.co.uk/monster/s...ad.php?t=53566
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Old 02-06-2019, 02:48 PM   #8
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Carb float chamber level valves and seats.???
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Old 03-06-2019, 09:04 AM   #9
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sounds daft but have you checked the timing marks line up on the belt pulleys? Had one before that was similar and it ended up being off by one tooth
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Old 04-06-2019, 09:59 AM   #10
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So carbs are off again checked float height already set at 14mm
Diaphragms seem sound
I have noticed that the needle is on the highest position I'm not sure what the default setting is
I'm guessing it's going to be letting a lot more fuel in
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