1982 200a with 65.5mm piston

[coreyp01]

hi all picked up a 1982 200a last year and did a few mods ( 12x28 mudzillas, snorkle, and 52 tooth rear sprocket). a few weeks ago it was getting pretty noisy (piston slap). pulled motor down ordered 65.5mm piston had cylinder bored out, re assembled. i guess i should mention i am a marine and motorcycle technician so far far from my first build or first performance build. cannot get this darn thing to run properly got it jetted i believe to be pretty darn close but it almost seams like i need a bigger carb has anyone else put in a 65.5mm top end and if so did you go with a 30mm carb? money is tight and i dont really want to buy it just for s&g and it not make the difference. thanks for any info.

[350for350]

I'm no expert on carbs, but I'd guess that a 30mm is way too big. Yours is probably a 22mm, while a 200X carb is 24mm. What is it doing to make you feel that it needs a bigger carb? What other mods did you do to it?

[coreyp01]

My 200a has a stock 24mm carb I do not remember off the top of my head what the standard bore is. 1st over for a 200x is 65mm bore and from what I have read on this forum it has a 27mm carb and guys are putting on xr200 carbs to pick them up which are a 30mm carb. I bored my cylinder to 65.5mm with a cam not sure what the cam is it was in a parts bike I bought and was lumpier than mine so I put it in upon assembly. Seeing as the guys running 200x are putting the xr200 carb on theirs at a 65mm bore I would assume I am. Going to need to xr200 carb with my 65.5mm bore but was hoping to get some confirmation

[350for350]

Well on the home page , on the left hand side, there is a link for Honda specs and brochures. According to this link, all of the 185s and auto clutch 200's have a 22mm carb stock. If yours has a stock Kehien carb that's 24mm, then it probably came off of a 200X. Just because you have a larger bore, you don't have to use a larger carb. You also have a bigger cam. You're getting there. Compression ratio? The 200X has a higher compression ratio than a auto clutch 200. How about the intake and exhaust/ You will need to be able to flow the amount of air that a 30mm carb will let through. If I'm not saying things that you like, try giving shortline10 or YaegerB a pm. They know A LOT more about the 200X than I do. They also know what to do to get more power out of them. Most of the performance ideas will carry over to your engine as well.

[coreyp01]

ok thank you for the info yes i found that my buddy has a 200x and we pulled and measured his car which is a 24mm carb. the parts bike i purchased had a slightly bigger carb on it it was a 25 or 26mm cannot recall off the top of my head. as far as compression ratio i am unsure what the compression ratio is with the new piston. as far as exhaust i cannot find a used dg or cobra near me without spending big money so i am currently working on building a custom 1 1/8" exhaust for it thank you for the info. i will try and contact him and see what he has to say.

[Gabriel]

Ok, I googled a couple of times and found squat. Post a picture if you have the time and inclination. I have never heard of or seen a 200'A'. Seen ATC, S, M, E, ES & X but never an A. I love seeing something new.

[350for350]

My guess is that it was a typo since the a and s keys are next to each other. Coreyp01, awesome on the exhaust. Post up some pics when you're done. I'd like to see it and others will too.

[Paul G]

I would like to ask if you used the head and rocker cover off the bike you took the cam from. Science you don't know the size of the cam it's possible the valve spring could be diffrent. I had to change mine when I went with a bigger cam. Could possibly be floating the valves at higher rpm. Causing lack of performance.

[coreyp01]

i will post up a picture of it tonight if i get a chance. i believe it be be a 200a because of the parts fiches in 82 they only show a 200a , 200ea, and 250ra. i will definatly post up some pictures when i am done i may post a new thread on the build start to fish to show the guys and gals how i did it if some one else was interested in doing the same or similar, hopefully starting on that tonight. i do have the head and cover for the other motor. i believe them to be stock length but i will defiantly double check. i do not believe that to be my problem. i cannot get any throttle response out of it and getting very little torque. i have played with jetting back and forth like cazy but i cannot get it to not foul plugs with anything more than a 92.5 main which is light to me as far as i am concerned, hence why i am leaning towards bigger carb (more air in) and exhaust (more air out).

[Gabriel]

i believe it be be a 200a because of the parts fiches in 82 they only show a 200a , 200ea, and 250ra.

Wonder if that's a canadian market only thing cause I never heard of any of those models.
This is a Honda right? Can't wait to see a picture of it.

[coreyp01]

Here a picture I have of it when I changed my rear sprocket. Yes it is a Honda. Altho the tank is off of a yamaha moto 4. I also put the rear rack on it. https://uploads.tapatalk-cdn.com/20180824/41f7d56a38256bf096d6d45700624b98.jpg

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[Paul G]

I had similar problem with a Honda 100 dirt bike never fouled plugs i rebuilt top end. It would cut out when throttle up and no torque. Friend of mine bought it from me and sent it to a shop. It had to do something with timing or the points. I checked the timing a couple of times I must have missed something. You could check that also. That was a few years ago he still rides it. I go over sometime a and ride it to. I'll keep thinking ! :D

[Paul G]

What color is your spark plug after you run it white or brown or black. that's a good indication of fuel mixture. Maybe vacume leak?

[coreyp01]

I marked the Tim NG plate when I took it off but it's definitely worth double checking with a light. If I run a 90 main my plug is white (lean) and anything over a 92 is black (rich). I stole a carb off a buddies dads 200x which has been sitting for 10 years but he will not part with. I am going to clean it and try it be Use altho it measures the same as my carb it Is a slightly different carb so we will see how that works out

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[Paul G]

Good luck hope it works out.��

[86125m]

your only second over you shouldnt even need to have rejetted the carb the stock carb with stock jetting should have been fine my atc 200m is .75 over with the stock carb with stock jets and I have a high compression piston. you said you are running a 24mm carb have you checked the spark plug to see if your running rich or lean. you may need to get a stock carb to get it to run correctly

[Paul G]

Did that carb work out for you.

[coreyp01]

just an update, got exhaust made up this weekend, got the carb on on Monday tried getting it jetted started at 108 main and 40 pilot, great throttle response but way way to rich would foul a plug to not running standards within 300 feet, kept playing with jets ended at 92 main and 38 pilot, still to rich which didn't make sense and had serious bog when throttle was smashed would practically die. after thinking long and hard about it i cam down to most of my carb problems came when i put the stock air box on. i should mention i originally bought this bike in pieces for 40$ with lots of parts missing and no compression. un-stuck rings found some parts and had it running good on a pod filter. so that being said i pulled the stock air box off late last night unit started and ran a bit better immediately less bog and now lean popping :) so over then next few days i will re-jet it back up and attach the snorkel tube right o the carb. will keep you guys updated as i get time to as i work roughly 60-70 hrs a week.

[Paul G]

Air restriction works in mysterious says glad to here making progress��

[350for350]

Yes it does.

[coreyp01]

30 mill carb came in early!!!!!! 254272. as you can see throut is a bit larger. ported intake to match size of carb and made gasket to seal properly to intake boot. made new 2" snorkle, got her running on jets that came in carb (chinese jets no number on jets) running rich with those jets swapped out to 38 pilot and 100 main seams better will have to try today it was really late when i got the new jets in last night.254273 heres the picture i have been promising

[350for350]

It looks like you're getting pretty close!

[Paul G]

You probably can take the carb apart with your eyes closed cool looking set up and tires. Going to take in deep mud holes looks like fun :Bounce sounds like a little more tuning and you'll have it !

[coreyp01]

Got her all set up haven't taken it for a ride ride yet but have rode a. Big around the yard and down the streets around me. This is how she sits in the end: 30mm carb 38 pilot 112 main, ported and possished intake plenum to match 30mm carb, cam, 1 1/8 custom exhaust, 2" snorkle, 28" mud zillas, 52 tooth rear sprocket, 250cc (65.5mm bore). Thanks for all the help along the way guys! https://uploads.tapatalk-cdn.com/20180911/d076f5072c219ef80781d78439954c36.jpg

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