Engine Rebuild...How difficult?

[DeePa]

As you know, I have an 85 200s thats under going a total resto. Only thing left in the frame as of now is the wiring harness, bc i wanna get pictures of how all the wires run before I take it out. The engine ran very well, besides a little smoke and some backfiring, but that was due to a clogged slow jet on the carb.

My first post here on 3ww was about a broken exhaust header stud in the cylinder head. I have yet to remove it, and one of my friends who owns a machine shop says he will do it, but he wants just the cylinder head. I have no experience with engine at all, and I figure if he wants just the head, I might as well rebuild it due to it having only 90-100 lbs of compression and a little smoke out of the rear end.

I have a clymers manual that has some fairly detailed instructions on what to do for the whole rebuilt engine procedure. But would I have to bore/hone the cylinder and then get a matching piston/rings? I guess if its in good enough condition, it should be ok without the bore/new piston, but why not make it perfect when its all disassembled?

Another Question, How much will an engine rebuild cost at the best/worst senarios? Best being new set of rings and gaskets, worst being sending the engine to wiesco to get it bored ect.

Do you think I'm capable of an engine rebuild, or should I take it to someone who knows what their doing. I can figure stuff out fairly well, and I would like to try it, but i dont want to trash a good engine just because I wanted to try something.

Thanks,
Mike DiPasquale

[thefox]

If you have read through the book and still feel comfortable about taking on the project then go for it, you can always post questions if you have them. I did my first engine rebuild from a Clymer manual; they are a good thing to have.

Prices can very. If you take it apart and find that the cylinder and piston are within the specifications and don't have any scratches then you may be able to get away with a new set of rings ($20) hone job ($20) and a top end gasket kit ($20).

If you have to bore then a bore job can cost $60 or so and a new piston with rings range from a cheap $60 set off eBay to a good wiesco for $110. Then also add the gasket kit ($20).

The true worst case would also include a new rod and crank bearings but on a 4 stroke that was running before you probably would have notice if they needed to be replaced (not very common on a 4 stroke).

You might want to reseat the valves since you are doing top end work anyways but they shouldn't need to be replaced if the trike was running. I would also check the cam chain; it might be worth spending the extra $20 now since you have it apart.

[jeswinehart]

i honestly can say if i am able to do it ,,, anybody can !
i done a upper rebuild a couple of weeks ago on a freinds 350x and it run him 148.00 dollars ( no labor cuz he's a buddy and i was just needing a garage project fix )
that included having the valves lapped in + cyinder honed just a little.
oem honda rings and a aftermarket gasket kit , 2 quarts of oil, 1 filter and a new plug.


go for it ,,,, if you get into anything that you have quistons about ,,, there is a wealth of free advice from some really good motor folks on here.

i would like to add that you will find that you are skipping back and forth in the manual ,,, it's just the way they put them together.

john

[DeePa]

Everything is going well so far, except nows the time for the cylinder head cover to come off, and all the necessary bolts are out, but it wont budge. I was slamming the **** outta it with a rubber mallet and it still wasnt budging. I dont want to put a screwdriver near there because I dont think it would do any good.

When they talked about the magneto pulse thing, what were they talking about? Is that the part of the CDI which is held to the cam with one 10mm bolt/washer and that little dowel pin which I am petrified that I am going to drop into the crankcase?


Other than that, everything went fairly easy, and the hardest part so far was getting the sprocket timing chain bolts out without it moving all over the place, but I managed.

If you know how to get that head cover off, please share the wealth

Thanks,
Mike

[Dammit!]

I rebuilt my first four stroke when I was like 12 or 13 with only a Clymers manual. Nobody to ask when I had questions. You have the internet. Jump in! :D

[Huffa]

"Everything is going well so far, except nows the time for the cylinder head cover to come off, and all the necessary bolts are out, but it wont budge. I was slamming the **** outta it with a rubber mallet and it still wasnt budging."

What bolts and how many did you take off? Also, ask before slamming!!!!!!!!!! :rolleyes:

"When they talked about the magneto pulse thing, what were they talking about? Is that the part of the CDI which is held to the cam with one 10mm bolt/washer and that little dowel pin which I am petrified that I am going to drop into the crankcase?"

Yes it is and that dowel pin should be pressed in I think?

[TrikerR]

you probably havent taken the timing chain off...dont feel stupid, i wondered why my jug and head werent coming off the first time i took my engine apart.lol

[DeePa]

The next step in the manual says to remove the cylinder head cover and it just wont come off. I took off the 4 cap nuts, and the 4 6mm alan screws. Everything involved with the CDI is off, as well as the 2 cam chain sprocket bolts are off. I Just think its the gasket acting as cement that hasnt moved in 20 years.

ANy other ideas? ANy think i Missed/Skipped?

The dowel pin is removable from the cam, or at least mine was

[short4stuff]

PULL HARDER!!

thats what i had to do .. there wasnt even a gasket on mine though .. it was just on there good and tight .. :S ..
Iduno what to say.

[Pistonhead]

I gave mine a tap with a dead blow mallet when it didn't want to come off, same with the jug.

[DeePa]

Update...still stuck. I took both valve covers off and put a piece of wire under the head and out through them, then tied it, put some gloves on, and proceeded to lift the enging back up 3 feet onto the table. How the hell am i supposed to do this? Do they make anything to eat away at the gaskets? What are the gaskets made out of?

DID i miss any steps that would case the head cover to be this much of a ***** to get off??? Do i have to remove the timing chain sprocket first? I wouldnt think so, but i dont know

I'm getting pretty pissed off, and I may have to call it quits for a few hours.

Thanks,
and any more ideas, please let me know.

[Huffa]

Your trying to get the very top off right? I'm almost certain you didn't remove the screws to the pulse base! Back one attaches to head cover and front one to cylinder head (just below screw driver). OOOPS, I believe you have this off already........ correct?

[DeePa]

Hey, yeah i got it off finally. It took a lot hammering, but it finally came loose.

Is there a gasket for the cylinder cover head?

Everythings disassembled now, piston out and everything. Theres a lot of carbon on the top of the piston, and a little on the top ridge above the highest ring, and goes about half way around the piston. Theres also a lot of carbon on the valves. I am trying now to decide wether or not I should have it rebored and get a new piston, or just put a nice new set of wiesco std rings on there. The cylinder is clean, and has no deep scratches or gouges, but it has a few hairline scratches. The piston has some hairline marks also, but its not too bad. I'[m really thinking about scraping the carbon off of the top of the piston, getting new rings and a gasket kit and reinstalling.

What benefits would I have over a bore and hone + piston?

Would it be worth the cost of (???)]

Thanks,
Mike

[Pistonhead]

Just remember that if you fix the problem for good (ie new piston etc.) you won't have to tear her down and go through all the camshaft and cdi crap again for a very long time.

[DeePa]

well where can I get the bore done?

I know wiesco does it best, but is it worth the price?

[Tri-ZNate]

well where can I get the bore done?


Check your local ATV/Dirtbike shop. We have two here in the middle of nowhere and they do everything. ex. bore, sleeving, engine rebuilds, ect...

[Huffa]

Wait a minute! You don't even know if it needs a bore till they put a dial indiacator in the bore and check it out! No use boring it out if it only needs a hone job to ready the bore for new rings!