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Discussion Starter #1
Had the Monster Dynoed last year and stored it till now..Still runs like a pig.
Today i went for run and as the kilo`s pass by the Monster started with the normal surging at normal speeds..(Just installed new plugs )
By the time i JUST got home the bike was running on half a cyclinder (A Scooter went pass me ) ..During the trip i poped the plugs off and found they had both had heavy black soot , and i noticed the vertical cylinder was worse and the exhaust was cooler as well..
When new plugs are fitted ( KLG ) the bike runs better and gives full throttle,but on cruising speeds it still surgers badly.. If i let it idle too long it fowls the plugs pretty quickly with alot of Backfiring and flames shoot out of the exhaust.. Tried playing with the mixture screws but with no luck..has strong spark..Nothing makes sense..I am a Motor mechanic but this problem is getting to the better of me..Hense getting it Dyno Tuned ..Same thing, ran great at first then back firing,sooty plugs and surging at cruising speeds..???
The bike has only done 15,00 Kilo`s

Cheers
Kevin

 

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Hi Kevin,

I too recently was having exactly the issues you are describing. And, yes, it was carburettion (but I think you already know that).

When you got it dynoed, did they actually replace anything in the carbs or just tweak the mixture screws as well? If it made no difference then perhaps they did not.

How many turns out are your mixture screws at the moment?

My electrics looked good too - A visual spark check looked good and testing the coils shows they were likely to be okay. To help diagnosis for coils/ignition controllers I simply swapped them left and right to see if the issue swapped cylinder. I didn't.

I took the opportunity to get the carbs out, give them a clean, an d while I was at it, put in a Factory Pro jet kit with new needle jets. I hear the stock ones can be worn by 5k miles (mine was 45k klms - so I just thought it best to replace then anyways).

The outcome? Problem gone. Others said they had similar problems and it was related to battery performance.

So, I'd be trying the following:

* charge the battery (just to be sure)
* check the air filter and make sure it is not filthy and therefore cannot pull enough air through it. If in doubt, replace it (or clean it if it is K&N/etc).
* Check your airbox snorkels are not obstructed.
* swap the coils and ignition controllers left and right to see if the problem swaps cylinder (only a 20 minute job)
* Wind your mixture screws right in then try going out in half turns - go around the block (not for a long ride) to see how it feels and check the plugs. Hopefully initially you will see it running lean and - if not, then it probably is a deeper problem than the mixture screws.
* Finally, get the carbs out, clean them, replace all seals and gaskets. Replace needle jet, perhaps while you are at it, install a Factory pro kit.


Greg.
 

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Discussion Starter #4
Hi Greg
Thanks for the reply..i have removed the carbs and cleaned them with no luck... Makes sense that the taper of the needle are worn..would explain the rich mixture at idle and low range cruising..will look into a Pro Jet Kit..
Cheers
Kevin
 

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Discussion Starter #5
Bloody Hell.. Doing a spark test, i had the fuel tank up,,Removed the lower cylinder plug lead .. started the bike and the Vertical cylinder running by itself on idle, well it wouldnt..So i tested it in reversed and the lower front cylinder would run on idle nicely while the vertical cylinder lead was removed and laying on the cylinder cooling fins..
Then a BANG ..I saw white things flying in the air before i relised that the top of the battery blew?? Must of had battery fumes lying around and the loose spark from the lead created a expolsion!!! The lead is at least 14inches away and out in the open on a windy day?? I feel like using some C4 and blowing the thing away..Off to get another battery..
Kevin
 

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Wow. Careful there.

With a bit of luck, maybe the battery was the issue! :)

Okay so you've given the carbs a clean.

I'm no expert and anyone can chime and tell me I'm wrong, but black sooty plugs would have to be mixture related in some way. So best to keep looking there perhaps.

When you had the carbs out did you check the float height? Factory Pro says they should be 14mm. My bike was running way rich and my float heights were 10mm and 12mm - so I corrected them to 14mm. A bad float height will screw it up (like i said, I'm not an expert but the Factory Pro guys *really* go on about it - ).

http://www.factorypro.com/tech_tuning_procedures/tuning_float_height_adj_procedure.html

http://www.ducatisuite.com/jetkit.html

Is the air filter clean? If it is dirty that will make it rich.

You didn't say how many turns out your mixture screws are. One of mine was 7.5 out (yes, you read that right) and that just ruined the running of the cylinder big time. They are both now at 2 turns out.

Is the gap on the brand of plugs you are using good for the monster? Considered a switch back to the stock Champion RA6HC to remove that as a factor?

Greg.

PS. The cooler air from one exhaust is a red-herring - I believe that is just the way it is. My monster is exactly the same, others here on the forum say that too.
 
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