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View Full Version : Hi comp piston, Machine isn't that fast..



CodyRosa
09-10-2013, 08:39 PM
Hey guys sorry for all these posts about the high comp piston..

Basically its all seated, not a single bit of smoke comes out anymore, starts first pull, idles great, and is a heck of a lot harder to start now.

So I had 22 inch tires, 11 40 gearing and it tops out at around 30.

Then I put 18 inch golf kart tires on with 13, 40 gearing and it tops out at maybe 35.

That last setup is just a tad quicker than the 22's. I'm giving it gas and its just not going anywhere very quickly. Before when it started smoking and losing compression/power it was topping at 40+

It feels as if I need to go down the teeth for the 22's just to have some acceleration. I have yet to pin the throttle so maybe it'd get up to 40 but it'd take forever! If anybody has any idea's on why its not that fast, nor has a lot of power please let me know

Thank you!

shortline10
09-10-2013, 10:17 PM
If your wanting more top end then a "real" performance cam is needed to gain RPM's

CodyRosa
09-11-2013, 12:28 AM
Really so my only option is a cam? I figured the thing would do 50 like a stock machine at least not 30. I don't even need top end to be honest just low end and some acceleration.

barnett468
09-11-2013, 06:05 AM
Hey guys sorry for all these posts about the high comp piston..

Basically its all seated, not a single bit of smoke comes out anymore, starts first pull, idles great, and is a heck of a lot harder to start now.

So I had 22 inch tires, 11 40 gearing and it tops out at around 30.

Then I put 18 inch golf kart tires on with 13, 40 gearing and it tops out at maybe 35.

That last setup is just a tad quicker than the 22's. I'm giving it gas and its just not going anywhere very quickly. Before when it started smoking and losing compression/power it was topping at 40+

It feels as if I need to go down the teeth for the 22's just to have some acceleration. I have yet to pin the throttle so maybe it'd get up to 40 but it'd take forever! If anybody has any idea's on why its not that fast, nor has a lot of power please let me know

Thank you!



Really so my only option is a cam? I figured the thing would do 50 like a stock machine at least not 30. I don't even need top end to be honest just low end and some acceleration.

A high compression piston does not mean it will have more rpm, it means that it will have more bottom and mid range.

at a certain point too much compression will reduce max rpm.

if it is running noticeably slower now than when you first built it then it needs to be dis assembled and inspected. the rings are not sealing or you heat seized it. doesn't matter if it doesn't smoke, this is what you did by running it hot and not properly jetting it as you described in your last few posts.

manbearpig
09-11-2013, 09:41 AM
how are you determining your speed? are you just guessing or is someone hitting you with a speed gun?

CodyRosa
09-11-2013, 09:57 AM
No its running the same speed as when I first assembled it. Nothings changed that way. I'm running just a tad rich right now. No i'm just guessing. I can tell its around 30 because i could only go 30 for a month with bad rings haha. (i'm used to it) and I could tell the smaller tires got me up faster. I guess i'll just have to live with it.. oh well it'll be a cruiser for my dad then.

Bren_downe
09-11-2013, 12:59 PM
I could be wrong but I thought larger tires were more top speed and smaller tires were more low end grunt?

CodyRosa
09-11-2013, 02:26 PM
Larger tires=more top end, lower acceleration
Smaller tires=more acceleration, lower top end

It just helps that I geared it. Only reason its faster with those tires. It'll still work for what I need it for. I was a little harder on today and its pretty quick. Nothing like it used to, it just sounds amazing now at least =D. Maybe i'll get a cam in the future but for now this will do just fine for me.

jb2wheels
09-11-2013, 03:55 PM
I missed something at the beginning.

Are you saying you rebuilt the top end in your 200M auto-X with a hi comp piston and it runs worse than it did before the rebuild?

RIDE-RED 250r
09-11-2013, 04:10 PM
If your jetting is correct, I would check your ignition timing! Those older engines that have the pulse generator mounted in the head and rotor mounted to the cam have adjustable ignition timing. If your timing is incorrect, the engine will NOT run to it's full potential.

And I agree with what others have said. A higher comp piston really won't give you more speed, but will get you there quicker. And like Barnett said, you can get to a point where higher compression will reduce your max RPM's.

For speed it should be as fast as it was before, but not necessarily faster.

CodyRosa
09-11-2013, 05:27 PM
Ride red, I'll try to get someone to go next to me so i can see the top speed. When i had the stock piston I got it up to 50 with 22's. Now I swear its only 30, 35 if that even. It was even quicker before then it is now. Its burning right, now. I never changed anything on my timing so that should be correct... maybe something got moved a tad when i took it all apart? It's worth it to check though.

It acts like its maxed out right when I get into 5th gear.. instead of 5th gear normally pulling for a few seconds. It has power I can feel it.. just doesn't feel like its opening up to its full potential I guess you could say..

Thanks for the suggestions so far though!

RIDE-RED 250r
09-11-2013, 06:23 PM
Cody, when you pulled the top end to replace your piston, I would bet you had to remove the ignition plate to pull the ignition rotor and then the cam gear.

It's easy to check the timing. Just remove the sight hole plug like you did for setting the cam timing. Get a timing light and 12v battery. Hook the timing light to the battery, and then the spark plug wire clamp to the plug wire, close to the coil. Start it up and let it idle. Shine the timing light into the sight hole and pull the trigger. The "F" mark should be visible and lined up with the index mark every time the timing light flashes on.


Unless I'm wrong about the early 200cc engines having adjustable ignition timing.. Someone please correct me if I'm wrong about that..


It's easy to do and well worth checking. And if timing is set incorrect, your engine will absolutely not be running to it's full potential.

Also, would be helpful if you put your helmet on and had someone get some video of you running it and how it's acting.

CodyRosa
09-11-2013, 08:02 PM
Well I removed it, BUT I took a picture and made marks and put it back in the same exact spot. I may just get a video tomorrow and upload it. It is worth checking, i just don't have a timing light right now.

rg97
09-15-2013, 04:41 PM
try these
-clean the carb and jets
-try an new plug
make sure you're brakes arent seized and causing the machine to not go fast because of friction

CodyRosa
09-15-2013, 06:44 PM
Oh i've cleaned it.. i've cleaned it a few times. I know one of the biggest culprits... awhile back I posted about bad gas.. and Barnett told me to check the color.. that color was brown and I had red koted my gas tank. All was great until I went to rebuild this top end.. I drained the gas and when I put new gas in after a day of sitting it turned... BROWN again.. I noticed some rust chunks in my clean fuel line. So my gas is bad once again which would explain the bogging through all gears going up any hills.

I ended up putting stock gearing back with the 22's and it runs a lot better.. to bad I blew a head gasket haha so I have another one coming and while im at it i'll check the ignition timing. I remembered when i first did my ignition (machine ran absolutely perfect!) the plate was all the way to the left for me.. well after awhile it had moved.. it moved to the right. Very noticeable. So when I tear it all down i'll switch that as well.

The bad gas would also explain why most of the settings I was doing wasn't really changing much.. kinda stayed lean until i really turned it in.

In about a week if it still doesn't run good after I put it all back together then i'll post back.. if not.. I must have figured it out thanks to you guys for the suggestions!

Jason125m
09-15-2013, 11:01 PM
How's your clutch? If the timing is right, my guess would be the clutch.

Does it sound like it keeps revving but is just not going any faster? If so, its the clutch.

Make sure to buy an oem head gasket... Aftermarket is junk for the 200x's.

hatc200x1
09-15-2013, 11:57 PM
Agreed on the aftermarket 200x headgaskets, COMPLETE JUNK, mine blew out. Put a OEM Honda in mine, and havent had an issue.

CodyRosa
09-15-2013, 11:58 PM
Its hard to explain haha.. Its just not quick, and it stalls a lot. I couldn't climb a sand hill 15ft up in 1st gear. I used this thing before for hill climbs worse then what i just tried with it now. Basically the only way i can get it up to 50 is on tar, and if i'm shifting correctly.. as in wide open throttle, shift, wide open throttle, shift etc etc. (if i have throttle half way, shift, it takes a bit to get up in speed.) I also found that when i'm on tar going 50 and hit the shoulder where its dirt I slow down to about 35 (speeds are guesses), so i have to downshift to 4th so i'm in the higher RPMS to keep it moving.

Basically last time it did this It was the bad gas.

Also Jason, this is a 185 bottom end with a 200m top end.



Just a little update as well... I took the trike on some trails and on the way home I hit a 2 foot drop off, bottomed out the trike and smashed my tail light holder haha.. anyways I lost the tail light yet still had my headlight.. i rode home with the headlight on.. it is a 55w up front.. shouldn't it have blown this bulb? Last time I had just a headlight it blew the stock bulb.. so i'm wondering if my spark is very weak? I'm running a D8EA for the plug and it is sparking great but i just thought this could be a possibility.

barnett468
09-16-2013, 06:40 AM
I took the trike on some trails and on the way home I hit a 2 foot drop off, bottomed out the trike and smashed my tail light holder haha.. anyways I lost the tail light yet still had my headlight.. i rode home with the headlight on.. it is a 55w up front.. shouldn't it have blown this bulb? Last time I had just a headlight it blew the stock bulb.. so i'm wondering if my spark is very weak?Why do you think your lite not going out measns you have weak spark?

its been suggested at least 3 times that you do a compression test but you have not done one yet. thee is no point making post after post regarding this if you don't supply any info.

CodyRosa
09-16-2013, 10:17 AM
Barnett I can't do a compression test. Absolutely wont happen. My threads are stripped a little and for whatever reason I can get a plug in just fine but I can't get a tester in there.

The light* was just a suggestion. If theres no taillight the headlight should blow. Obviously my voltage is weaker then it used to be.. because i've blown one before on this same machine. Why all of a sudden is it not blowing?

once again.. just a suggestion

yaegerb
09-16-2013, 10:29 AM
Barnett I can't do a compression test. Absolutely wont happen. My threads are stripped a little and for whatever reason I can get a plug in just fine but I can't get a tester in there.

The light* was just a suggestion. If theres no taillight the headlight should blow. Obviously my voltage is weaker then it used to be.. because i've blown one before on this same machine. Why all of a sudden is it not blowing?

once again.. just a suggestion


I have a refurbished 200x head with brand new valve seals just waiting for someone to buy it and the best part is the spark plug threads are perfect. PM me if you are interested.

CodyRosa
09-16-2013, 10:40 AM
sending pm haha

RIDE-RED 250r
09-16-2013, 07:23 PM
Cody, blowing one light will not cause the remaining light to blow as well. The voltage regulator is what keeps the voltage in the lighting circuit in check so the bulbs don't blow.

And consequently, the ignition and lighting circuits are 2 separate systems. The stator has 2 sets of windings in it, one set to power the ignition system, and another separate set of windings that powers the lighting system. You can lose one and the other will still work. So having said that, a malfunction in one circuit will not adversely effect the other circuit. The obvious exception is if the entire stator fails all together.

But this is a topic for a whole other thread... ;)

CodyRosa
09-16-2013, 11:39 PM
Ride red, i'm fairly certain 200x's don't have voltage regulators. At least mine doesn't. Thats why I blew my first set of bulbs, one blew which caused the other to blow.

But oh well it was just a suggestion. Once I buy yaegerbs 200x head i'll do a compression test.. haven't been able to do one of those ever on this machine lol. Stripped the threads 7+ months ago.

Jason125m
09-17-2013, 07:46 AM
yep,, 83-85 200x's do not have voltage regulators.

Regardless I wouldn't worry about why your bulb isn't blowing, it could be possible your bulb is rated for a higher wattage then oem.

If you say your threads are basically stripped, why would you not think this could be a cause of poor performance?

They're pretty easy to drill out and repair. My beater 125 is good as new after fixing the PO's mistake.

CodyRosa
09-17-2013, 09:43 AM
Oh I don't think the threads have anything at all do to with performance. I was just telling barnett that I can't get a compression tester in there. I would just fix them BUT I think every hole is stripped on the head lol. Both exhaust are stripping, the one for the CDI is stripping. I guess these things strip out quite easy =/

RIDE-RED 250r
09-17-2013, 07:21 PM
OK fair enough. Thanks for correcting me on the voltage regulator guys. :beer