Electric start issue - Page 3

lego1970 · 10-17-2009, 08:28 PM

That is a pretty big difference in compression.

Not to get off the subject but you mentioned the one way deal on the starter, like a slipper clutch on a sportbike. Is that how most starters are built on motorcycles or just common on Chinese bikes? I'm not going anywhere with this question, but just curious.

islandboy312 · 10-18-2009, 04:13 PM

Starting the engine with the timing mark inspection plug removed is a Very Bad Idea. I painted myself and a 62 T-bird with a hurricane oil spray.

Even with a clear plug, there'd be much oil moving to see the timing marks when running. With no breaker points, I don't know how to static check the timing. The bike runs too good for it to be off very much.

My engine is an OHC, and I can't see an easy way to get a look at the cam gear and chain. If anyone knows how to check the cam timing without pulling the engine, I'd love to know. When adjusting the valves, the TDC marks on the crank seem to coincide with the low point on the cam lobe, but I can't be sure.

Next test is to check voltage drop at the battery during cranking, then compare to voltage drop at the starter during cranking. If the starter relay contacts are skuzzed, I may be getting low voltage at the starter, and not enough RPM. Maybe that's why the jumper cable test to the battery didn't work.

I changed ignition coils, and now the bike will start on electric starter - but not often, and not happily. I'll take the small improvement while looking for the root cause.

Lego - All the bikes I've done starter work on - mostly Japanese, and one Harley Shovelhead - have constant engagement starter gears. An automotive Bendix arrangement is too bulky for a bike, and the one-way clutch isn't strong enough for a V-8.

In the meantime, I'm riding the Roketa. Thanks, guys.

FastDoc · 10-18-2009, 04:20 PM

Next test is to check voltage drop at the battery during cranking, then compare to voltage drop at the starter during cranking. If the starter relay contacts are skuzzed, I may be getting low voltage at the starter, and not enough RPM. Maybe that's why the jumper cable test to the battery didn't work.

Good thinking. Maybe that's why my 'jumper cable test' failed. Still an odd problem!

lego1970 · 10-18-2009, 05:42 PM

Islandboy, Thanks for the reply.

Weldangrind · 10-18-2009, 06:03 PM

Quote:

Originally Posted by islandboy312

My engine is an OHC, and I can't see an easy way to get a look at the cam gear and chain. If anyone knows how to check the cam timing without pulling the engine, I'd love to know.

Removing the rocker cover is the only foolproof way. With the engine at TDC and the timing inspection plug removed to reveal the T mark, the cam gear will have some form of reference. On '85 through '04 XR250 engines, the cam gear has a horizontal mark on either side of the gear that line up with the surface of the head. On my son's '80 XR200, the cam gear has a small mark above the top bolt, and you just make sure that it is 90 degrees to the head surface. Your cam gear will have an obvious indicator like that.

BTW, my buddy brought his XR over for some help and we discovered that his cam gear was one tooth out. It ran like that, but not very well.

islandboy312 · 10-22-2009, 08:00 PM

Okay. My pilot screw was adjusted way too rich. It was 2 turns out from closed, works for some folks, but not me. I set it at a little more than half a turn out. The bike now starts with electric starter just like it's supposed to.

I arrived at the final setting by standing behind the running bike and sniffing until my eyes didn't water. I live at 2000 ft, but go from sea level to 6000ft regularly. Big ride on the 8th, 0-10,000 ft. We'll see.

I'm ashamed. The pilot circuit jerks a bunch of people around. I should have known better. Thanks for all the ideas.

Weldangrind · 10-23-2009, 02:35 AM

Glad to hear that it starts with the electric starter now (and glad that your eyes aren't burning), but that still doesn't explain the cranking compression difference. Are you happy enough with it, or are you inclined to check the cam at TDC?

FastDoc · 10-23-2009, 11:46 AM

All's well that ends well, but still some mystery in there... :?:

lego1970 · 10-23-2009, 02:19 PM

Good deal, As posted above the compression thing is odd, but for what it's worth, I've been odd for 38 years and I'm still running fine

Ok, that was cheesy! Anyway glad ya got it starting with the electric starter.

10-18-2009, 04:13 PM	#32
islandboy312 Join Date: Jul 2009 Posts: 13	Note to self Starting the engine with the timing mark inspection plug removed is a Very Bad Idea. I painted myself and a 62 T-bird with a hurricane oil spray. Even with a clear plug, there'd be much oil moving to see the timing marks when running. With no breaker points, I don't know how to static check the timing. The bike runs too good for it to be off very much. My engine is an OHC, and I can't see an easy way to get a look at the cam gear and chain. If anyone knows how to check the cam timing without pulling the engine, I'd love to know. When adjusting the valves, the TDC marks on the crank seem to coincide with the low point on the cam lobe, but I can't be sure. Next test is to check voltage drop at the battery during cranking, then compare to voltage drop at the starter during cranking. If the starter relay contacts are skuzzed, I may be getting low voltage at the starter, and not enough RPM. Maybe that's why the jumper cable test to the battery didn't work. I changed ignition coils, and now the bike will start on electric starter - but not often, and not happily. I'll take the small improvement while looking for the root cause. Lego - All the bikes I've done starter work on - mostly Japanese, and one Harley Shovelhead - have constant engagement starter gears. An automotive Bendix arrangement is too bulky for a bike, and the one-way clutch isn't strong enough for a V-8. In the meantime, I'm riding the Roketa. Thanks, guys.
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10-18-2009, 04:20 PM	#33
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	Next test is to check voltage drop at the battery during cranking, then compare to voltage drop at the starter during cranking. If the starter relay contacts are skuzzed, I may be getting low voltage at the starter, and not enough RPM. Maybe that's why the jumper cable test to the battery didn't work. Good thinking. Maybe that's why my 'jumper cable test' failed. Still an odd problem! __________________ Happy to serve.
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10-22-2009, 08:00 PM	#36
islandboy312 Join Date: Jul 2009 Posts: 13	I'm an idiot Okay. My pilot screw was adjusted way too rich. It was 2 turns out from closed, works for some folks, but not me. I set it at a little more than half a turn out. The bike now starts with electric starter just like it's supposed to. I arrived at the final setting by standing behind the running bike and sniffing until my eyes didn't water. I live at 2000 ft, but go from sea level to 6000ft regularly. Big ride on the 8th, 0-10,000 ft. We'll see. I'm ashamed. The pilot circuit jerks a bunch of people around. I should have known better. Thanks for all the ideas.
	0

10-23-2009, 02:35 AM	#37
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Glad to hear that it starts with the electric starter now (and glad that your eyes aren't burning), but that still doesn't explain the cranking compression difference. Are you happy enough with it, or are you inclined to check the cam at TDC? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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10-23-2009, 11:46 AM	#38
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	All's well that ends well, but still some mystery in there... :?: __________________ Happy to serve.
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10-17-2009, 08:28 PM	#31
lego1970 Join Date: Apr 2008 Location: Blue Springs, Missouri. United States Posts: 505	That is a pretty big difference in compression. Not to get off the subject but you mentioned the one way deal on the starter, like a slipper clutch on a sportbike. Is that how most starters are built on motorcycles or just common on Chinese bikes? I'm not going anywhere with this question, but just curious.
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10-18-2009, 05:42 PM	#34
lego1970 Join Date: Apr 2008 Location: Blue Springs, Missouri. United States Posts: 505	Islandboy, Thanks for the reply.
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10-23-2009, 02:19 PM	#39
lego1970 Join Date: Apr 2008 Location: Blue Springs, Missouri. United States Posts: 505	Good deal, As posted above the compression thing is odd, but for what it's worth, I've been odd for 38 years and I'm still running fine Ok, that was cheesy! Anyway glad ya got it starting with the electric starter.
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