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-   -   84 XT600 starts hard cold, and refuses to start hot (https://www.horizonsunlimited.com/hubb/yamaha-tech/84-xt600-starts-hard-cold-50986)

bobthebiker 22 Jun 2010 22:54

84 XT600 starts hard cold, and refuses to start hot
 
I just got this bike, and I know I can start the freakin thing despite being 100 pounds or so, but when its hot, I'm kicking like a lunatic to even get it to BACKFIRE. choke, no choke, throttle, no throttle, nothing makes ANY difference, it just spins over, backfires and wont start after that. I dont get it.

it acts like I'm flooding, making me suspect float height is an issue, but I couldnt begin to know what the right height is, and I need to find the proper pilot screw settings, otherwise much as I love having an enduro, I wont be able to hang onto this thing.

anyone got some input? I'm dead broke and about to lose my sanity.

zigzag 23 Jun 2010 00:36

hi there ive got a 85 43f and if it throws a mood on me it can be bad news, it did this when i first got it , it had been stood semi dismantaled for a few years and for the first couple of months it would be ok on one startup then a pain the next, the thing what seemed to help was a realy long blast one spring day ( i bought it in the depth of winter) i would surgest a good service new plug , clean re lube the air filter clean the carb or at least flush some fresh fuel through it , check tappets also check the decompresser cable is set right . with everything set up i slowly kick the bike till i here the decompresser click ,then let the kick starter return to the top then a good long kick all the way is the trick not a short stab at it . i have my mixture screw set i think at 3 to 3.5 turns out . you could also check all the electrical connections are ok and there is no dodgy wiring . zigzag

bobthebiker 23 Jun 2010 01:12

Thank you! I have a new air filter and spark plug on my list. I checked the gap on te plug earlier and it seemed quite wide, which I recall causing significant starting difficulty on other machines I've run, so I closed the gap and it really helped.

I just went through the carb and cleaned it thoroughly today because, well I'm obsessive. still need to do valve tappets, it sounds like one or two are loose at operating temperature, what is the correct clearance for the intake an exhaust tappets?

I rode mine home a good 20 or so miles, and it never gave me the least problem then, but I think it needs a general tuneup nonetheless. Fortunately, I can do the work myself, which saves money and time.

bobthebiker 23 Jun 2010 05:02

Zigzag, your input was spot on. turns out I wasnt able to kick the bike over quick enough because 1. I'm a skinny twig, and 2. the compression release was needing a proper adjustment. now it kicks over a little easier at least, letting me kick it over quicker, and actually letting me START the effin thing. now I just need to get a better exhaust and rejet it..... or just rejet in general. I have that unpleasant surging at 3000-3500rpm, and its irritating.

Thank you for your info, you helped me immensely.

zigzag 24 Jun 2010 00:01

hi there glad things are inproving , the tappet clearances are inlet 0.07-0.12 mm ex 0.12-0.17 mm set cold, plug NGK DPR8EA-9 gap 0.8-0.9 mm , some info says to fit a DPR7EA-9 , same gap applys , its just a hotter running plug. the decompresser cable free play measured at the lever on the head is 0.5 mm do this the same time as the tappets, top dead center on the compression stroke. good luck zigzag

bobthebiker 24 Jun 2010 00:16

I appreciate the input. My XT is making progress toward being a dependable daily ride for me right now, which makes me extremely happy. next up is registration and the wheel bearings.


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