Elstar Tank 250cc Pushrod - Wont Crank

Ruddles75 · 02-07-2021, 05:14 AM

Hi All,

I am working on my Dads roughly 8 year old Elstar Tank Quad.
Its a 250cc Pushrod OHV Air cooled engine (CG250??)
It cranks fine with the Spark Plug out but wont turn over with spark plug in.
My Brother Adjusted the valves and replaced positive and negative leads and connections
Removed the exhaust in case of blockage.
Changed the Battery, Starter motor and solenoid.
No change to behavior.
No stuck valves that we can see when the valve cover is removed.
A friend that works for KTM said to have a look at the Auto-decompression system - said the small spring can break.
He showed me a CAM from a OHC KTM bike with a spring and a nub on the cam setup that opens the Exhaust valve at cranking speeds.
Would anyone know if the 250cc Pushrod OHV engine has a similar setup?
The Hawk 250 Bike seems to have a very similar engine and I have watched guys upgrade to "Performance Cams" but cant see any kind of Auto-Decompression System.

Any Ideas would be appreciated.

franque · 02-07-2021, 07:09 AM

It doesn't have a decompressor, I'm not aware of a single Chinese motor with a decompressor, they're generally pretty low compression. When it fails to turn over, is it buzzing, or does it seem like it wants to turn over and fails? Are you positive that it's not turning over? Is it possible that the valves were adjusted with the crank on the wrong cycle, a.k.a. the crank was 360° out?

TxTaoRider · 02-07-2021, 08:10 AM

Sounds like you have a project!

Do you know if it was running before you started working on it?

Have you ran a compression check on it?

Are the ground cables good clean and connected tight to the engine? Some of the cables on these bikes are really cheap and corrode at the crimps.

If you're sure theres no mechanical interference, like valves hitting, then will it turn over by pushing it in 4th or 5th gear?

FLASHLIGHTBOY · 02-07-2021, 01:14 PM

Hello... ok.. first do a compression test... what is it???/ need 60-90 lbs compression... if you have this... can you turn the engine over by hand??? with or without plug in???? if you can and have this compression.... next jump the starter right at the positive connection... ground to the frame...... with a good battery it should crank over..
You have to make sure you have compression and a good battery... check back in..

02-07-2021, 05:14 AM	#1
Ruddles75 Join Date: Feb 2021 Location: Camden Posts: 1	Elstar Tank 250cc Pushrod - Wont Crank Hi All, I am working on my Dads roughly 8 year old Elstar Tank Quad. Its a 250cc Pushrod OHV Air cooled engine (CG250??) It cranks fine with the Spark Plug out but wont turn over with spark plug in. My Brother Adjusted the valves and replaced positive and negative leads and connections Removed the exhaust in case of blockage. Changed the Battery, Starter motor and solenoid. No change to behavior. No stuck valves that we can see when the valve cover is removed. A friend that works for KTM said to have a look at the Auto-decompression system - said the small spring can break. He showed me a CAM from a OHC KTM bike with a spring and a nub on the cam setup that opens the Exhaust valve at cranking speeds. Would anyone know if the 250cc Pushrod OHV engine has a similar setup? The Hawk 250 Bike seems to have a very similar engine and I have watched guys upgrade to "Performance Cams" but cant see any kind of Auto-Decompression System. Any Ideas would be appreciated.
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02-07-2021, 08:10 AM	#3
TxTaoRider Join Date: Oct 2020 Location: Flower Mound Texas Posts: 904	Sounds like you have a project! Do you know if it was running before you started working on it? Have you ran a compression check on it? Are the ground cables good clean and connected tight to the engine? Some of the cables on these bikes are really cheap and corrode at the crimps. If you're sure theres no mechanical interference, like valves hitting, then will it turn over by pushing it in 4th or 5th gear? __________________ 2021 Tao Tbr7 - "Lucille" Mods so far- Brozz swingarm, 21" front rim (Bridgestone Tw302 rear/Dunlop D606 front tires), Digital gauge cluster, pz30b pumper carb, after market hand guards, aftermarket brake and clutch levers, round fold away mirrors, Fly handlebars shortened slightly, 13t front sprocket 2009 Q-link Legacy 250 1982 Suzuki GS1100ES - "Jolene"
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02-07-2021, 01:14 PM	#4
FLASHLIGHTBOY Join Date: May 2009 Location: SASKATOON Posts: 1,161	compression Hello... ok.. first do a compression test... what is it???/ need 60-90 lbs compression... if you have this... can you turn the engine over by hand??? with or without plug in???? if you can and have this compression.... next jump the starter right at the positive connection... ground to the frame...... with a good battery it should crank over.. You have to make sure you have compression and a good battery... check back in.. __________________ DEALER FOR ZSTAR & GIO PRODUCTS, TAOTAO ABIBABA ATV ETC
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02-07-2021, 07:09 AM	#2
franque Join Date: Nov 2017 Location: Marseille, France -> Conakry, Guinea Posts: 1,481	It doesn't have a decompressor, I'm not aware of a single Chinese motor with a decompressor, they're generally pretty low compression. When it fails to turn over, is it buzzing, or does it seem like it wants to turn over and fails? Are you positive that it's not turning over? Is it possible that the valves were adjusted with the crank on the wrong cycle, a.k.a. the crank was 360° out?
	0