New to me...1985 200X....metal shavings in the oil

[BigRedGrizzly]

Ok got it. Bore it to 66. New piston kit to match bore. Since the valve springs appear to be or are performance grade I need to get a cam that will work with 66 piston, the DG after market exhaust, and the valve springs. I'm thinking this cam.

[yaegerb]

yep, that's the one I use in my 200x motors. Nice cam.

Also, I assume you are using a 24MM keihin. I would thoroughly clean that carb, and rebuild it with a shindy kit. Go to jets r us and get a 110, 112 main jet. Leave pilot at 40. Start with a 112 main and lower your needle clip 1 slot. That should be enough for your mods. I would also upgrade your air filter to a uni if you haven't already.

[knappyfeet]

O.K. I'll be the square of the bunch and say why don't you just source a good stock cam? Maybe a new timing chain as well. How is the bore? Is it worn? Does it need to be bored out to 66? If the standard bore is serviceable I might leave it alone....if its serviceable.

The old XR motors of the day were finely tuned performance engines in stock form. They were designed with ease of starting, good performance, ride ability, nice power bands and dependability. What someone came in and did was install a cam, leave the stock bore, stock intake and carb.....probably jetted it poorly and drilled holes in the air box.....all of which destroyed what Honda engineered into this motor. Sure it might be quicker in a 500 rpm range somewhere near redline but if your not living there all this is a quick fix.

Just for my 2 cents......instal stock cam, new timing chain,,check rockers, hone the bore and see if its within limits and serviceable, new rings and ill bet new valves are in order as well. Then you can adjust jetting sizes.

[yaegerb]

O.K. I'll be the square of the bunch and say why don't you just source a good stock cam? Maybe a new timing chain as well. How is the bore? Is it worn? Does it need to be bored out to 66? If the standard bore is serviceable I might leave it alone....if its serviceable.

The old XR motors of the day were finely tuned performance engines in stock form. They were designed with ease of starting, good performance, ride ability, nice power bands and dependability. What someone came in and did was install a cam, leave the stock bore, stock intake and carb.....probably jetted it poorly and drilled holes in the air box.....all of which destroyed what Honda engineered into this motor. Sure it might be quicker in a 500 rpm range somewhere near redline but if your not living there all this is a quick fix.

Just for my 2 cents......instal stock cam, new timing chain,,check rockers, hone the bore and see if its within limits and serviceable, new rings and ill bet new valves are in order as well. Then you can adjust jetting sizes.

Great suggestion for OEM. Personally I like to put my own spin on motors....to each his own.

[knappyfeet]

Great suggestion for OEM. Personally I like to put my own spin on motors....to each his own.

I'm with you on that.

What a lot of folks don't understand is practically any motorcycle engine is a high performance motor....even your singles, tourers, etc......all have a performance history engineered into them. Some mistake a motorcycle engine for a chevy 350...where you change a cam here, intake there and get some performance enhancements due to the way automobile engines are manufactured. Not so in a typical motorcycle engine.

[BigRedGrizzly]

Hmm... Decisions..decisions. Thanks for routing me through the options. The cylinder is in fine shape which is making me NOT want to bore it. But since the valve springs are beefed and we believe the cam may be beefed as well it's making me want to put the same profile came in it. Would putting the stock profile cam in there have any adverse effects on the valves, springs, rocker arms or cam itself since the springs are a bit beefed? Pardon my ignorance but is there such thing as a hi performance stock size piston? For example, would I benefit from having a 65mm Wiseco piston over a OEM 65mm piston. If so, I may consider that.
Thanks again crew.

[knappyfeet]

Hmm... Decisions..decisions. Thanks for routing me through the options. The cylinder is in fine shape which is making me NOT want to bore it. But since the valve springs are beefed and we believe the cam may be beefed as well it's making me want to put the same profile came in it. Would putting the stock profile cam in there have any adverse effects on the valves, springs, rocker arms or cam itself since the springs are a bit beefed? Pardon my ignorance but is there such thing as a hi performance stock size piston? For example, would I benefit from having a 65mm Wiseco piston over a OEM 65mm piston. If so, I may consider that.
Thanks again crew.

I honestly don't want to change your mind. Everyone likes what they like and that's great. If you are going to install all these performance upgrades and not do the most crucial part (and most expensive....machining head, larger intake manifold, carb, etc) then you results and ride ability might suffer.

[yaegerb]

Hmm... Decisions..decisions. Thanks for routing me through the options. The cylinder is in fine shape which is making me NOT want to bore it. But since the valve springs are beefed and we believe the cam may be beefed as well it's making me want to put the same profile came in it. Would putting the stock profile cam in there have any adverse effects on the valves, springs, rocker arms or cam itself since the springs are a bit beefed? Pardon my ignorance but is there such thing as a hi performance stock size piston? For example, would I benefit from having a 65mm Wiseco piston over a OEM 65mm piston. If so, I may consider that.
Thanks again crew.

yes, here is a std. bore with higher compression ratio.
http://www.ebay.com/itm/1981-1985-Ho...e4ea27&vxp=mtr

I know that your cylinder walls look great, but you need a machine shop to tell you if its perfectly round. If its not, then you might as well do an overbore and larger piston.

[BigRedGrizzly]

Ahh.. I understand now. One cannot simply look at the cylinder and say "yeah, it's good". Measurements need to be taken to verify that. Got it. I'm not looking to make a hi performance machine. I was dealt a machine with some hi performance parts in it. I intend on keeping this 200X for a long time to ride with my family. Ideally, I'm looking to invest my money in longevity and efficiency. From reading earlier in this thread it sounds like if it is bored to 60 I can use the OEM carb but will need to adj. the jets. I'm ok with that.
I make the decision tonight.....

[atc007]

Just skimming fast, Sorry if this was mentioned. Always, measure a piston at the widest part ,which is bottom of the skirts , opposite of the wrist pin. IN/EX. Good advice here to tune ya right up

[Jmoozy27]

I like the idea of slightly modifying it. Mild cam, first overbore, 10.25:1 broken in properly will be loads of fun and still dry reliable.

[barnett468]

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Hello all... I finally found a 200X what appears to be in pretty good condition. It feels like it's lacking the power my 200s has. The X definitely doesn't wheely as easily. I'm not I'm not 100% sure what my next move should be. I've heard from some that a complete upper and lower rebuild is required. Chassis is sound. Engine has me concerned. Any guidance on which step or steps I should take next would be appreciated.

Is your 200s stock?


RACING HISTORY

Just because a company has a racing history, it does not mean that the engines they put in the production bikes are even remotely close to the same as the ones they put in their race cars, and in fact, I can guarantee you that they are not . . If Honda made a CRF200, it would probably have 30% more hp and probably weigh 20% less than yours.

ATC’s just like yours are intentionally designed to provide MODERATE performance and be easy to operate so people with moderate riding skill can easily handle them . . If someone wanted a high performance box stock 3 wheeler, they would be buying a “Tecate…The Worlds Most Powerful 3 Wheeler” and a good life insurance policy.


GOALS

The above being said, you can easily get 30% more hp from your engine, so you simply need to decide exactly what you want out of it . . If it were mine, I would probably build it so it had around 200 hp and was barely rideable, if I was going to give it to my 14 year old kid whom has limited riding skill, I would leave it basically stock but add a pipe so it sounds cool and they would think that they are going fast.

After you decide what you want, I would ask here how to achieve that goal . . Yeagerb mentioned that he has the exact same Web cam you are looking at, for so you can ask him if his engine is something he would let an inexperienced young rider operate etc.


CAMSHAFT

Measure the width of the lobe also and with the height information, we can guestimate how “big” of a cam it is.

As I mentioned, that cam will have a small but still noticeable, greater amount of power with a 10.25 compression piston . . I can also see that your engine was burning at least a little oil so it had to be at least a little down on compression from stock so even just redoing the top end with a stock piston will increase the power albeit by probably a small margin.


COMPRESSION

If you are using 91 octane gas or higher, you can run a 10.25 piston without fear of detonation, therefore, if you want more power than stock and better throttle response than stock, there is absolutely no reason not to run a 10.25 compression piston, but obviously, the choice is yours . . I will add that increasing the compression will make it slightly harder kick over, but by the sounds of it, it probably won't be much harder to kick over than your 200s is . . If you want it as a training tool for your kids, than I might just leave the compression and cam stock but still bore it out, but only go .25 mm [.010"] over if I could find a piston that size.


CARBURETOR

The higher the compression, the more volumetric efficiency your engine will be . . This means, that as volumetric efficiency increase, the carburetor size should or could be increased.

The higher the rpms, the bigger the carb should be because the greater the air flow requirements are.

The XR200, is a more powerful engine that the ATC200x and it revs farther and it has a bigger carb . . If I increased the compression, and the cam size, I would definitely increased the carb size proportionally, which in your case would be by around 2 – 3 mm . . This size increase is also a very conservative one . . I have seen people run much bigger carbs than this in these engines but that doesn’t mean they weren’t too big . . I was 16 once too, and at that time I thought that if I put a 900 cfm double pumper Holley on my nearly stock 265 ci Chevy engine, it would magically have 100 more hp, lol.


BORING THE CYLINDER

I wouldn’t even waste my time measuring a 30 year old cylinder that obviously burns oil . . Yes, some of the oil might be from the valves guides but it doesn’t matter . . The truer the bore is, the better the rings will seat which equates to more compression and the LONGER it will last before you have to do it again.


BORE SIZE

Although you will get more power from a 1 mm over piston than you will from a .5 mm over piston, it will be a very, very small amount, therefore, I would only bore it to .5 over . . The benefits of this are that you will not only have an additional bore you can now do if needed, but it will in fact run slightly cooler because of the slightly thicker cylinder wall, and after all, it is an AIR cooled engine.

[barnett468]

.
Ok, the small end of your camshaft that rides inside the steel bushing is junk . . This means the bushing is likely junk, so I would simply buy a new one from the site below . . They also have a stock cam if you want one.

In my experience, this bushing is a weak area as I have seen many cams scored like yours, so unless yeagerb or someone else has a better way to get oil to it, I might consider sending it out to get a lubricity coating on it . . The two best ones are either moly WOS2 or tungsten disulphide WS2 . . NASA used the tungsten dry on the NASA space rovers and one of them is still going around 10 years later and it weighs around 408 lbs, lol . .

You could even get it for your cam, and the other bearing surface on your head and valve cover and these parts will basically last forever and it’s fairly cheap to do.

http://www.cmsnl.com/honda-atc200x-1...4.html#results

http://www.cmsnl.com/honda-atc200x-1.../#.VY3GaVLLDdV




Here's a bit more info on the tungsten disulphide coating.


WS2 TUNGSTEN DISULPHIDE

Rockwell hardness 30 hrc.

Load bearing capability is 100,000 - 300,000 psi.

Has better dry lubricity than any other substance.

Coefficient of Friction is 0.07 static, 0.03 kinetic/dynamic.

For comparison, the kinetic/dynamic coefficient of friction for Moly is around 5 times higher at 0.19 static, 0.16 kinetic/dynamic.

The coefficient of friction reduces the higher the load is.

It can also be used in high temperature and high pressure applications and offers temperature resistance from -450 F to +1200 F.

Thickness after application is .5 - 1.0 microns [0.0000196 - 0.000039] therefore it will have absolutely no affect on clearances.


Coatings don't get much cooler than this stuff.
.

[barnett468]

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CYLINDER HEAD VALVES

At the very least I would spray carb cleaner in each port one at a time then look at the valve to see if it is leaking or weeping . . If it is you can decide what to do then.


VALVE SPRINGS

As far as your valve spring question goes, yes, you should put lighter springs in if you run a stock cam because it will make the cam, head, valves, and rocker arms last longer.

[BigRedGrizzly]

Wow guys! All great advice. I need time absorb it all and thoroughly check things out. Here's some work I did today disassembling.