Senior Clinician
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Post by jjoshua20213 on Nov 7, 2014 23:02:28 GMT -6
I got a bad kit off ebay and when I first put it on everything went well. around 100 miles after it started loosing power and eventually stooped starting. I was able to adjust the valves a couples times and squeeze around 30 miles out of it each time. Eventually I noticed the valve wouldn't adjust above .002 even with the screw out. Eventually it lost almost all compression. Put stock head on and its fine. Checked the old one and valve seat on the exhaust valve looked rough. What happened? lol and what caused it? it was a 50mm kit. Put stock head back on and everything is fine. I ride it hard daily. Got other heads and big valve head at really good prices when I complained(Go Figure), and they all had the same result. Ran really good to start and quickly died. I ride it at really high rpm. At what rpm do the valves usually float?
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Post by cyborg on Nov 7, 2014 23:27:40 GMT -6
Valve float can happen in different rpm ranges it all depends on spring pressure , weight of the valves themselves,,,lots of different factors can contribute to this condition ,,, soft metal in the seat or the valve itself can cause the valve to receed into the head and make it impossible to maintain clearance ,,, cheap parts sometimes are more expensive in the big picture
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Post by cyborg on Nov 7, 2014 23:30:46 GMT -6
Can you post some pictures of the failed heads ?,,, I'd really like to get a look at them
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Ad Free Donut
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A bike is music to my ears.
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Post by Guitarman on Nov 8, 2014 0:25:46 GMT -6
My guess is springs combined with too thin oil. Not enough heat transfer.
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Doc's Anything Goes
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Post by tvnacman on Nov 8, 2014 2:39:51 GMT -6
Sorry to hear about your trouble . I would keep the engine with a BBK out of the high rpm . Make the power or speed with gearing and variator weights . The stock connecting rods don't like the extra weight of the piston for long . I have even seen people with + mm cranks break connecting rods .
John
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Post by Bashan on Nov 8, 2014 8:40:44 GMT -6
I've had the RPMs up to 9K for short periods and did OK. I blew one at 9.5K so I wouldn't go past 9 and then don't hold it at that.
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Senior Clinician
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Post by jjoshua20213 on Nov 9, 2014 1:13:04 GMT -6
I got rid of all the heads. The tach on my other bike with almost identical mods read up to 10,000. it went past that. Judging by the space between the intervals I would say it maxed out around 12,500 up a slight incline going 50. I use these bikes for transportation, but at the same time I know i'm abusing them. Its fun testing the limits and i'm prepared for failure.
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Ad Free Donut
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A bike is music to my ears.
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Post by Guitarman on Nov 9, 2014 1:42:35 GMT -6
As long as you know it's going to explode on you, then I say go for it.
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Doc's Anything Goes
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Post by tvnacman on Nov 9, 2014 6:10:36 GMT -6
I got rid of all the heads. The tach on my other bike with almost identical mods read up to 10,000. it went past that. Judging by the space between the intervals I would say it maxed out around 12,500 up a slight incline going 50. I use these bikes for transportation, but at the same time I know i'm abusing them. Its fun testing the limits and i'm prepared for failure. Stay out of areas without shoulders , I broke a belt on the hwy with no shoulder and blew an engine again on the hwy with no shoulder . For the record they were two different hwy . The cagers don't give you much respect and pass very close . John |
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