Clinician
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Post by triplej56 on Jul 28, 2012 8:00:23 GMT -6
we kind of think that we are getting to the bottom of our problem.our cam chain does measure 41 links.what i am going to do,is get a new 70cc kit,that comes with a cam(our old 80cc kits did not come with a cam).We will find out what is going on with a little bit of measuring.If we are ok with our new kits I will let u all know.Do not want anyone to run into the problem we are experiencing
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Post by triplej56 on Jul 20, 2012 10:53:47 GMT -6
hey Roy trying to find a chain stretcher with no luck(LOL).
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Post by triplej56 on Jul 18, 2012 7:47:00 GMT -6
I am starting to think it would be best to find another engine block.When we take this engine out I will see how many links are in the chain and compare it to one we are putting in,that is not going to have a problem.Will keep you guys informed as to what is going on.
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Post by triplej56 on Jul 17, 2012 11:07:11 GMT -6
we do not know exactly what had happened to this different(old engine) we put in.It had no cycliner and head,but the crank seemed ok and cam chain seemed fine.We just put the new cyclinder and head on which measured the same as the old engine we were replacing with the bad crank.On the old engine we were not to happy with the scaring of the old cyclinder and valves,that is why we put new ones in.Both engines again read 139QMB.I will say again guys this sure is one dam confusing issue!
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Post by triplej56 on Jul 17, 2012 3:28:10 GMT -6
Chain guides in place,as far as the tensioner,forget it.That chain is so tight you my as well throw the tensioner away.Sorry guys,but we did repairs for 6 years with no problems.We close 1 year and back in business now and all of a sudden the dam Chinese are doing all there bull to get me out the business.Sorry but we just do not know what exactly is going on.We got a feeling we need 1 or maybe 2 more links in the cam chain.My could be measurements is telling me 2.Again guys sorrry,but in the past we replaced many engines,etc.You name it we most likely did it.Back to where I started,we just never run into this.Maybe the Chinese sent us a oddball engine.Would sure not put it past them(lLOL)
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Post by triplej56 on Jul 16, 2012 22:31:10 GMT -6
ok let me clarify the cam will NOT seat in the cradle due to the chain being too tight Before the nuts are put on the top of the bracket there is a 1/4 inch gap between the bearing on the cam opposite of away from the cam gear and the cradle where it is supposed to sit.the chain becomes super tight if you force the cam into place and put the top bracket with the valve rockers on .if you install the engine and attempt to run it the chain breaks within 5 minutes of engine running.<<<this is from my mechanic as of today please let me know if there is a cam with a smaller gear or if someone carries a longer chain so we can install the tensioner again
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Post by triplej56 on Jul 16, 2012 10:31:38 GMT -6
John I am out of town but will do it later when I return to shop.
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Post by triplej56 on Jul 16, 2012 9:17:31 GMT -6
John it looks like 1 of our new heads measures 2-3/8ths inches or very close.
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Post by triplej56 on Jul 16, 2012 8:55:26 GMT -6
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Post by triplej56 on Jul 15, 2012 19:20:40 GMT -6
Will do tomorrow John when I go to the shop.We did make sure the gaskets were all removed before we put new ones on(base gasket and head gasket).
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Post by triplej56 on Jul 15, 2012 17:09:41 GMT -6
The old head and new head both measure the same.We even measured two old head and they are the same.The chain is on the crank properly with no kinks in it.I know because I even double my mechanic on them.Keep plugging guys.
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Post by triplej56 on Jul 15, 2012 11:28:11 GMT -6
We have checked the engine designations and both read QMB139.
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Post by triplej56 on Jul 14, 2012 12:55:06 GMT -6
Help!! We just got back in the scooter business for repairs on Chinese scooters(after a year of shuting business down),and now we seem to be running into a big time problem.Wish my mechanic would send this e-mail(because he could verify what is going on),but unfortunately he does not get involved with computers.Guess I will g ive it a shot(please be gentle to me guys if I screw things up)(LOL!) It seems our problem is two different engines on the 50cc chinese scooters.One engine we were trying to replace because of a bad crankshaft with another engine we had(both 50cc,s).New engine we put in had a good crank so we put it in with a new cyclinder(piston and rings),new cyclinder head(all from Parts for scooters).Now bear with me guys,because I could screw this up(because I am certainly not much in the mechanical aspect of what is going on).Also not the best typer,but again bear with me and I will try my best. We had the timing set on the magnetic rotor(or some people call the ( as far as I know) flywheel). We got the cam gear all lined up and ready to put on the camchain.Camchain installed and ready to tighten down the camseat.Unfortunatly we are about a 1/4 inch away.We gave it a shot to tighten,but when we did seat everything,it was one heck of a tight cam chain(could not even put the chain tensioner in it).We went back to the drawing board to try and figure out what is going on.In our previous experience we had never run into this before.Anyway no luck so far to solve our problem.So we decided to do a little bit of measuring.We measured from where the crankshaft,say goes into the variator and to any point on the engine block.Well though and behold we found out the engine we took out was a 1/4 inch shorter than the one we put in.Now we knew why the cam chain was so tight.We have tried all our scooter parts places.No luck on different cam,cam gear,crankshaft etc.Cam chain maybe?Longer link length(guess you have to take out the crankshaft if it is possible?Sorry if I am getting long on this e-mail but we sure need help!I know some of you guys are pretty dang smart,so we sure appreciate any help you can give us.
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