28 lbs of compression, 70cc hensom

smokeeater · 09-09-2008, 11:29 AM

So I have finally had time to check over my son's nearly new hensom 70cc. We bought it new in april 07, he drove it quite a bit on the sandy trails in northern michigan last summer. It sat thru the winter and had electrical problems last spring. Then, by June it quit running. I guess I am looking for anyone's thoughts on this while I start tearing it apart. I'd like to know of similar experiences and reputable people to buy rebuild kits from. :evil:
Is the thing even worth rebuilding? Will new parts be better than original. The thing that sold me on this atv is that its supposed to be a "honda clone". I won't fall for that false advertising anymore. I was very diligent about keeping the airfilter clean. I changed the oil 3 times last year. I would guess he drove it 300+ hours. Did it wear out? I don't know. I post what I know

red2003 · 09-09-2008, 12:31 PM

At 300 hours, it is due for a rebuild under the best of conditions, let alone running in sand, which is very hard on things. As far as Honda replacement parts, probably not gonna happen. None of the bigger engines like the dual sport bikes match up at all. Were it me, I would just buy a new engine if the rest of the avt is worth it. The smaller engines, like yours and even the bigger 110's and 125's are cheap on eBay. They should all bolt right in and go.

IronFist · 09-09-2008, 01:03 PM

http://toronto.kijiji.ca/c-cars-vehi...QAdIdZ72497728

I found these guys on Kijiji here in Toronto. If they are up here, you guys have them 10/1. I'd rather go 100miles to talk to someone in person. But that's just me. Red's right. A brand new engine isn't that much, especially down there.

Cal25 · 09-09-2008, 01:03 PM

How much did the whole thing cost? 300 hours at a couple of bucks per hour for ownership. Buy a new one and keep the old one for spare parts.

warrior91 · 09-09-2008, 08:21 PM

300 + hours and only 3 oil changes probably did NOTHING for longevity on an air cooled,underpowered, china quad.
Sand trails with crappy air filter...Cleaned regular or not ,damage can be done in the first minute with silica dust in the cyl/rings, :roll: The factory filters don't seal or filter that well :roll:
:wink: Some tweaking and these bikes run great though :!:
I personally don't like to run more than 10-15hrs between oil changes no matter honda,yam,Loncin,Lifan.....Oil is cheapest,best thing you can do for your bikes maintanence...

smokeeater · 09-10-2008, 09:06 AM

I might have overestimated with the hours a bit. I still feel the thing should have lasted more that a summer season. I was riding right along side of him most of the time with my 16 year old trx250. Its still got the original piston and ring running in it. I guess I was expecting a little more out of thing. I saw one engine on ebay for 250.00, but it was for a 50cc. What I would like to know is, if anyone has done a rebuild and what there experience was with it. Did the cylinder look all scored? was it just a bad ring? blown head gasket?

frostbite · 09-10-2008, 09:51 AM

Out of curiousity, what should the compression be for an engine of this size?

smokeeater · 09-10-2008, 01:53 PM

I am not sure, I can't get a manual on it. I was expecting it to be 80 +

red2003 · 09-10-2008, 03:22 PM

Not sure what the compression should be, but for sure 28 lbs ain't enough. Tear it apart and find out what's up. Could well be a burnt valve. If so, that's an easy fix if you can find a replacement. It's hard to make a prediction when you say it just quit running. Unless it was a part failure like a valve, compression isn't a toggle switch. It would still start, just not as easy as when new, and you would have noticed a gradual loss of performance. Rip the head off it and look around. You'll see the culprit.

katoranger · 09-10-2008, 05:12 PM

Compression I would guess to be about 120psi in good condition and it should still run at 90psi.

I am thinking that a valve is not closing.

Have you tried putting some oil in the cylinder and kicking it over a few times and then do a compression test to see if it improves. If you get improvement then normally that is a sign of rings needing attention. If no improvement then likely a valve problem.

Also I bought a 125cc off ebay that was used for about $150.

Allen

smokeeater · 09-10-2008, 06:42 PM

thanks for reminding me of that. I'll try it this weekend

DesertDog · 09-11-2008, 10:23 AM

and if you plan on coming thru N.Nev soon i will give you one of my last 3 remaining 90cc quads, shipping is to much , so there free while they last and i'm not advertising.
and yes they're new

DD

AZ200cc · 09-11-2008, 02:00 PM

Quote:

Originally Posted by DesertDog

and if you plan on coming thru N.Nev soon i will give you one of my last 3 remaining 90cc quads, shipping is to much , so there free while they last and i'm not advertising.
and yes they're new

DD

Hell of an offer, How much is shipping?

LynnEdwards · 09-12-2008, 12:00 AM

Have you adjusted the valves?

Is this a GY6 honda clone? There are zillions of manuals out there for this engine for free. It may be for a scooter instead of an ATV but they are the same basic engine.

I have a new chinese 150cc ATV. I haven't had to face any of this engine work yet. The engine is running great with 30+ hours of heavy riding (and one crash).

Lynn Edwards

smokeeater · 09-12-2008, 10:40 AM

How do I figure out the engine style? And where do I find the manual? No I haven't looked at the valves, yet. I am at work a lot right now

09-09-2008, 11:29 AM	#1
smokeeater Join Date: Mar 2008 Location: metro detroit Posts: 24	28 lbs of compression, 70cc hensom So I have finally had time to check over my son's nearly new hensom 70cc. We bought it new in april 07, he drove it quite a bit on the sandy trails in northern michigan last summer. It sat thru the winter and had electrical problems last spring. Then, by June it quit running. I guess I am looking for anyone's thoughts on this while I start tearing it apart. I'd like to know of similar experiences and reputable people to buy rebuild kits from. :evil: Is the thing even worth rebuilding? Will new parts be better than original. The thing that sold me on this atv is that its supposed to be a "honda clone". I won't fall for that false advertising anymore. I was very diligent about keeping the airfilter clean. I changed the oil 3 times last year. I would guess he drove it 300+ hours. Did it wear out? I don't know. I post what I know __________________ <div align="left">hensim 70cc atv, son's<br />'92  250x, mine<br />'01 recon, hers<br />'95 xcr 600<br />'89 four winns <br /></div>
	0

09-09-2008, 12:31 PM	#2
red2003 Join Date: Jan 2007 Location: Northern Vermont, USA Posts: 1,227	At 300 hours, it is due for a rebuild under the best of conditions, let alone running in sand, which is very hard on things. As far as Honda replacement parts, probably not gonna happen. None of the bigger engines like the dual sport bikes match up at all. Were it me, I would just buy a new engine if the rest of the avt is worth it. The smaller engines, like yours and even the bigger 110's and 125's are cheap on eBay. They should all bolt right in and go. __________________ First Chinabike: 2006 Roketa RSX200E Current Chinabikes: 2023 Titan DLX & 2022 Lifan KP Mini w/ 210cc BRT kit, 22 RWHP!
	0

09-09-2008, 01:03 PM	#3
IronFist Join Date: Apr 2007 Location: Toronto Ontario Canada Posts: 2,585	http://toronto.kijiji.ca/c-cars-vehi...QAdIdZ72497728 I found these guys on Kijiji here in Toronto. If they are up here, you guys have them 10/1. I'd rather go 100miles to talk to someone in person. But that's just me. Red's right. A brand new engine isn't that much, especially down there. __________________ IronFist ___________________________________ The "chain" of command is used for beating spammers. ___________________________________
	0

09-09-2008, 08:21 PM	#5
warrior91 Join Date: Nov 2007 Location: N.E. Saskatchewan, Canada Posts: 679	300 + hours and only 3 oil changes probably did NOTHING for longevity on an air cooled,underpowered, china quad. Sand trails with crappy air filter...Cleaned regular or not ,damage can be done in the first minute with silica dust in the cyl/rings, :roll: The factory filters don't seal or filter that well :roll: :wink: Some tweaking and these bikes run great though :!: I personally don't like to run more than 10-15hrs between oil changes no matter honda,yam,Loncin,Lifan.....Oil is cheapest,best thing you can do for your bikes maintanence... __________________ '91 Yamaha Warrior- stage 2 '83 Honda ATC 70 '08 Yongjiang 125cc mx (Loncin) '08 Yongjiang 150cc atv (Jinlong)
	0

09-10-2008, 09:06 AM	#6
smokeeater Join Date: Mar 2008 Location: metro detroit Posts: 24	I might have overestimated with the hours a bit. I still feel the thing should have lasted more that a summer season. I was riding right along side of him most of the time with my 16 year old trx250. Its still got the original piston and ring running in it. I guess I was expecting a little more out of thing. I saw one engine on ebay for 250.00, but it was for a 50cc. What I would like to know is, if anyone has done a rebuild and what there experience was with it. Did the cylinder look all scored? was it just a bad ring? blown head gasket? __________________ <div align="left">hensim 70cc atv, son's<br />'92  250x, mine<br />'01 recon, hers<br />'95 xcr 600<br />'89 four winns <br /></div>
	0

09-09-2008, 01:03 PM	#4
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	How much did the whole thing cost? 300 hours at a couple of bucks per hour for ownership. Buy a new one and keep the old one for spare parts.
	0

09-10-2008, 09:51 AM	#7
frostbite Join Date: May 2006 Location: Fredericton, NB, Canada Posts: 1,744	Out of curiousity, what should the compression be for an engine of this size? __________________ Frostbite "The beatings will continue until moral improves"
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09-10-2008, 01:53 PM	#8
smokeeater Join Date: Mar 2008 Location: metro detroit Posts: 24	I am not sure, I can't get a manual on it. I was expecting it to be 80 + __________________ <div align="left">hensim 70cc atv, son's<br />'92  250x, mine<br />'01 recon, hers<br />'95 xcr 600<br />'89 four winns <br /></div>
	0

09-10-2008, 03:22 PM	#9
red2003 Join Date: Jan 2007 Location: Northern Vermont, USA Posts: 1,227	Not sure what the compression should be, but for sure 28 lbs ain't enough. Tear it apart and find out what's up. Could well be a burnt valve. If so, that's an easy fix if you can find a replacement. It's hard to make a prediction when you say it just quit running. Unless it was a part failure like a valve, compression isn't a toggle switch. It would still start, just not as easy as when new, and you would have noticed a gradual loss of performance. Rip the head off it and look around. You'll see the culprit. __________________ First Chinabike: 2006 Roketa RSX200E Current Chinabikes: 2023 Titan DLX & 2022 Lifan KP Mini w/ 210cc BRT kit, 22 RWHP!
	0

09-10-2008, 05:12 PM	#10
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	Compression I would guess to be about 120psi in good condition and it should still run at 90psi. I am thinking that a valve is not closing. Have you tried putting some oil in the cylinder and kicking it over a few times and then do a compression test to see if it improves. If you get improvement then normally that is a sign of rings needing attention. If no improvement then likely a valve problem. Also I bought a 125cc off ebay that was used for about $150. Allen __________________ You meet the nicest people on a Honda Clone.
	0

09-10-2008, 06:42 PM	#11
smokeeater Join Date: Mar 2008 Location: metro detroit Posts: 24	thanks for reminding me of that. I'll try it this weekend __________________ <div align="left">hensim 70cc atv, son's<br />'92  250x, mine<br />'01 recon, hers<br />'95 xcr 600<br />'89 four winns <br /></div>
	0

09-11-2008, 10:23 AM	#12
DesertDog Join Date: Apr 2008 Posts: 782	and if you plan on coming thru N.Nev soon i will give you one of my last 3 remaining 90cc quads, shipping is to much , so there free while they last and i'm not advertising. and yes they're new DD
	0

09-12-2008, 12:00 AM	#14
LynnEdwards Join Date: Aug 2008 Location: Tracy, California Posts: 83	Have you adjusted the valves? Is this a GY6 honda clone? There are zillions of manuals out there for this engine for free. It may be for a scooter instead of an ATV but they are the same basic engine. I have a new chinese 150cc ATV. I haven't had to face any of this engine work yet. The engine is running great with 30+ hours of heavy riding (and one crash). Lynn Edwards
	0

09-12-2008, 10:40 AM	#15
smokeeater Join Date: Mar 2008 Location: metro detroit Posts: 24	How do I figure out the engine style? And where do I find the manual? No I haven't looked at the valves, yet. I am at work a lot right now __________________ <div align="left">hensim 70cc atv, son's<br />'92  250x, mine<br />'01 recon, hers<br />'95 xcr 600<br />'89 four winns <br /></div>
	0