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Two questions
- charwood89
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My next question is related to this. About 1300 miles into said trip, the bike didn't want to start when hot. The starter motor would crank her over just fine and she would usually fire up, but if for some reason I shut it off or it died, I could crank it until the battery died without so much as a sputter. Push starting worked fine. At the same time, my idle started becoming rough, and she would missfire and die sometimes if I let off the throttle. I'm suspicious that the hot running mentioned above may have compromised my plugs. They're pretty coated in white scale. Is it likely that my problem is as simple as that, or should I look to valve lashings, etc?
Thanks much,
Casey
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- Born Dead 2
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- TeK9iNe
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Is the bike stock? Sounds like your jetting is too lean, maybe for the altitude you were at?
I've had the same issue, and just needed to get more fuel in there. Don't forget, fuel is a lubricant, and assists in maintaining proper combustion/engine temperatures.
You can sometimes help this situation by adding more mixture at idle. (Turning the pilot mixture screws appropriately, for your carbs.)
Someone else with more exp. will likely chime in soon...
Cheers.
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- fixer5000
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1978 kz650b pretty much stock
\\\\\\\" get there fast but arrive alive \\\\\\\"
massachusetts
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- charwood89
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I was wondering about the valves, so I'll check those. However, the problem only developed within the last 400-500 miles. Before the last leg of my trip I never had trouble with starting, cold or hot. Is it conceivable that the valve clearances could go outta whack that fast? I've never gotten it as hot as this last trip, so I suppose it may have never manifested itself for that reason as well.
Thanks so much for the input thus far. Forums like this are lifesavers.
Casey
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- bountyhunter
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Running richer definitely runs cooler.I may be jetted lean as well, it's true. The last owner put pod filters on, and I don't know whether he re-jetted to accomodate, but if I go up a size or two from stock, then maybe I'll run cooler?
Hope you are running synth oil considering how hot you were getting it.
1979 KZ-750 Twin
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- charwood89
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Running richer definitely runs cooler.
Hope you are running synth oil considering how hot you were getting it.[/quote]
I'm not actually... :dry: I run short oil change intervals with a high-shear diesel oil like rotella or delvac. I've been told that they hold up well in air cooled bikes, but should I really switch to a synthetic?
Also, because I can't seem to find my shop manual handy, does anybody know off hand what the recommended spark plug gap is?
Thanks,
Casey
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- KOOL RYDER
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I use NGK B7ES - the engine likes these much better for in town / freeway use at ~70 F
When I go on a long distance trips I often use B8ES. But, if you are running a lot of miles in one day at highway speeds and are in an area where the ambient teperature is high + 80 F , you should try B9ES and run 20 W 50 weight oil. The engine will thank you for it.
My 0.02 cents.
KR
Rockin\' a KZ650B2 since 2007 and a KZ 1000E since 2008
1978 KZ650B
1979 KZ1000ST
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- TeK9iNe
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I still use the B8ES plugs though.
I just got a colortune plug, and re-jetted, and now my bike runs alot smoother/cooler in 90+ temps all day long.
I had symptoms much like yours before this.
...and yeah, super hot temps can mean a temp no gap condition suddenly on valves that are already very tight. Had that problem last year, and it does make the bike VERY hard to re-start.
Cheers.
PS. recommended gap for mine is between .28 - .32
Try the .32, if it stammers at high rpm, then close the gap some, as it might be straining your ignition system.
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- bountyhunter
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charwood89 wrote:
bountyhunter wrote:
Running richer definitely runs cooler.
Hope you are running synth oil considering how hot you were getting it.
I'm not actually... :dry: I run short oil change intervals with a high-shear diesel oil like rotella or delvac. I've been told that they hold up well in air cooled bikes, but should I really switch to a synthetic?
Syns hold up better under extreme temps. The stuff you are using is really good, I just think syns work better at the extreme end of the temp range.
I also vote that B6ES is a good plug for city ONLY riding, but too hot for highway use and WAY too hot for highway riding in warm weather. B8 is probably a better choice for the latter service.
1979 KZ-750 Twin
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- bountyhunter
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7 - 8 mm which is .028 - .032".charwood89 wrote:
Also, because I can't seem to find my shop manual handy, does anybody know off hand what the recommended spark plug gap is?
Thanks,
Casey
1979 KZ-750 Twin
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- donthekawguy
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Rathdrum Idaho
1971 Kawasaki g3ss
1972 Yamaha R5 350
1965 Suzuki Hillbilly
1964 Yamaha 125
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