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Discussion Starter · #1 ·
considering that things expand and tighten as a motor gets hot, mine gets way tighter and considerably harder to kick over. So hard that if I dont give it my all, it'll snap back on me. The motor was rebuilt this winter by a shop, is it possible they set the rings too tight? 84" shovel
 

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Depends on lots of variables. How many miles since the rebuild? Valves might still be burning in. What kind of valves and the grinds they used also factor in. My rebuilt shovel was easier to kick over hot, but I don't see why it won't vary. Until it wore in, I had to kick it carefully. Do you just kick, or do you try to time the kick in terms of the engine cycle? I wrote a technique post a while back somewhere about how to start a stroker/bigbore. I can rewrite it if it'll help.
other Alex
 

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Same problem on a buddy's motor. Turned out the pistons were just a tad to big for the bore...as in, the cylinders were not bored to the individual piston....hope this helps man.
 

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Check your ignition timing as well. Whenever your motor is hot, the pistons will have actual hot spots on them and can cause pre-ignition. Check your tune (summer heat adds to this as well) and go from there.
 

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Do a cold compression test, and then a hot compression test. If it is considerable higher hot, you could have a tight bore. As stated, make sure your timeing is dead on, or a little retarded, which helps with kickstarting. Carbs can do that too, specially if the float bowl is set perfect for riding, but not high enough for sitting on the kickstand. Bowl fills, overruns into the intake and weeps past the open or almost closed valve, and floods the combustion chamber. Points or EI? if points, make sure they are square to each other, and the gap set on a averave between the pointed and the flat cam lobes on the advance unit. The advance unit is another area that most people don't do much maintainance on, a little grease on the pivots, and check the weight springs for being broke or streched.
 

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Discussion Starter · #10 ·
thanks for all the tips guys. I retarded the timing a tad last night and it seemed to help a bit. The compression test will be on my list of things to do as well. But I think this winter will result in top job - checking rings and bore and hoping finding that that is where the issue lies.

Tigeralex, thanks for the link.

Shovithead, i noticed everyonce in a while, when the bike starts it'll throw a quick flame out of the pipe(s), could that be a sign of the float level being off and letting gas through the intake?
 

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Have you actually static timed the bike? Retarding may help, but if it was too far advanced in the first place, then you just made it a little better. Try static timing it and see if that helps.
 

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Alex, it could be, but the best way to know, is to find out what the float bowl level should be, and then allow for extra lean, if your bike is not stock. If you adjust the float to much, it will starve for fuel on the hard runs, so there is only so much you can adjust, before it rears its ugly head again. If it leans more than a stock bike, then I would allow for that, or get a taller kickstand. You could try a 2x4 under the kickstand, to see if that is your problem. The fire out the pipes could be several things.
 

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Discussion Starter · #13 ·
i know my float is ballpark where it should be, and my bike has more of a stock lean than it did a few weeks ago, and the hot starting issues haven't changed, but starting in general has gotten a little better. Adjusting the float to sit closer to the bottom of the carb would be the idea - less gas filling the bowl leading to less leak into the intake? are my thoughts in the right direction? And my bike has only been static timed, I mark the spot and fine tune from there.
 

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Really sounds like timing to me.

If the motor was tight; you'd have a noticeable loss of power when hot. Iron cylinders are famous for this - motor will make good power cold, then power drops off as the motor tightens up.

If that's the case, then the motor is too tight.
 

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i know my float is ballpark where it should be, and my bike has more of a stock lean than it did a few weeks ago, and the hot starting issues haven't changed, but starting in general has gotten a little better. Adjusting the float to sit closer to the bottom of the carb would be the idea - less gas filling the bowl leading to less leak into the intake? are my thoughts in the right direction? And my bike has only been static timed, I mark the spot and fine tune from there.
The float setting in the factory manual, should tell you where to set the float. You can alter it a little, with no running issues. But if you drop it to much, it will affect your highway running if you are heavy handed. So you have to balance the height to keep it from dumping into the cylinders, if that IS the problem. Try putting a timing light on it, and see where the timing mark is. There are many more things, that could be the problem, so you could be chasing a problem, that does not exist. Set the bowl, run it hot, and see if it will crank. Points? or EI? It it is EI, and the unit has settings, that could be your problem, or even flooded spark plugs. Badly adjusted pushrods can do it too. If they are a little tight, and it gets hot, you could have one valve, not closing all the way, and that will cause hard starting too. Or maybe even the muffler bearings. lol
 

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I know what it is: The motor was built with insufficient main bearing (gear shaft and pinion shaft) end play, cold. Side-to-side. When it gets hot, it expands and tightens up the whole flywheel assembly. Will require an entire tear down to fix. Sorry!
 
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