Taking off the head

Rob Hoehn /

So I have to take the head off on my Batavus to bring it into a machine shop. Is this pretty hard to do?

Re: Taking off the head

no, it should be easy to do. i don't know batavus ... but on most mopeds the head is attached by four bolts to the cylinder. use a socket (probably either 10mm or 11mm) to undo the nuts (leave the bolts!). then your head slides right off. so does your cylinder.

what are you having done to your head? you may not need to take it in. let us know first.

Re: Taking off the head

Don't forget to torque the head nuts right.

Re: Taking off the head

Rob Hoehn /

The guy that had the moped before me messed up the threads and had them rethreaded and then put in a heli-coil. He did it wrong though and the heli-coil insert comes out with the spark plug. I called my local machine shop and they said that could just weld some metal in there and re-thread it at the right diameter. Doesn't that make more sense than messing around with an insert??

Rob

Re: Taking off the head

Like Rasta said, you're going to have to find out the torque specifications for your moped's cylinder head when you go to put it back on. You're also gonna need a torque wrench to tighten the nuts properly.

Re: Taking off the head

maybe batavus is more touchy than other mopeds ... but we don't use torque wrenches to put the heads back on. and we take heads off all the time. we just use regular socket wrenches and make sure to put the nuts back on in an "X" pattern. seems to work fine; we get great compression.

also, you mentioned that the hellicoil comes out w/ the spark plug ... was the rethreading done at the head? if that's the case, you might be better off just seeing if you can find a new (used) head ...

Re: Taking off the head

A torque wrench in my opinion is noit neccesary to put a head back on as long as you have a feel for it. But if you want to nit pick then i have seen Husky torque wrenches at Home Depot for 25 dollars. I have one and it is not that bad for a lower price torque wrench.

Re: Taking off the head

Ron Brown /

Miguel,

I don't normally pick on your posts, but someone who is asking how to take his head off strikes me as relatively inexperienced with wrenches.

Besides, I seem to remember a thread about head studs ripped out of the crank case not too long ago. Did you do this with, or without a torque wrench?

The only relationship between your peds compression and head bolt torque is that you have very little after stripping the threads. The torque specification is determined by the thread diameter and pitch, type of material it is screwed into and the material the stud is made of.

You should never "wing it", or recommend that someone else does, unless you are sure they have used a torque wrench frequently or stripped enough threads to know how not to do it.

Go sit in the corner and contemplate this :-)

Ron

Re: Taking off the head

Rob Hoehn /

I took the head off last night and boy did I find alot of surprises. First, there had to have been no compression, b/c one of the bolts was missing. There was carbon along the side that was missing a bolt. There was a pretty good amount of carbon build up that I couldn't see before by just looking through the exhaust port. I am taking it to a machine shop today to see what they can do with it. Thanks all for your advice and I will use a torque wrench just to keep it safe.

rob

Re: Taking off the head

Ron Brown /

You're a wise man Rob Hoehn.

Re: Taking off the head

ron:

thanks for the advice. i'm sure torque wrenches would work better. but they're more expensive and, as you pointed out, the torque wrenches seem to be very specific? everyone i know uses regular socket wrenches and goes very carefully and slow, so i never heard otherwise. we've gotten really good compression by just taking tiny turns on the head bolts using an X pattern.

and you're right, a while ago i had stripped bolts in my head. but they were striped from before and i tried to fix them (by inverting them into the head). i learned A LOT about my moped during those several agonizing weeks. it took taking two engines apart and switching internal gears, cluthes, etc. to get the bike running again.

i'm NOT a guru or anything like that. i don't think i've ever pretended to be. but i try to give a bit of advice when i can. i try to leave the tough jobs to others.

Re: Taking off the head

Ron i have to agree with u and correct my post above. A torque wrench is a very wise thing to use. I did not use a torque wrench on my kinetic and i stripped one of the bolts. After that i had a feel for it, and it all worked out all right. Something to mention though is that when i recently got a torque wrench the torque on the head was at 4, suppose to be at 6.5(i think so). Anyways i'd go with what Ron said and use the torque wrench, especially since he helped me out with all my trouble.

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