cy 26 cc lack of power

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Garethw1986

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right i posted last week about my zenoha running bad so i removed the head and chaged gaskets only to find its a cy engine:lol: ive put it back together and replaced carb and its better but still not right, when rear wheels are off floor she revs fine but when rolling she bogs down,is this piston ring? or clutch? cheers lads
 
what was the plating like when you rebult it,,,the reason i ask is i had the same thng a few years back car would not rev underload but would when rear was raised
i changed carb/clutch as mentioned above no real change so i stripped it down and the plating was patchy and dull so it maybe time for a new head if im wrong its ony going to cost you abit of time and a gasket,if im right and i hope for once im not its a new headkit not the end of the world remember santas watching,you may be on the good boy list with me
 
renbar said:
what was the plating like when you rebult it,,,the reason i ask is i had the same thng a few years back car would not rev underload but would when rear was raised
i changed carb/clutch as mentioned above no real change so i stripped it down and the plating was patchy and dull so it maybe time for a new head if im wrong its ony going to cost you abit of time and a gasket,if im right and i hope for once im not its a new headkit not the end of the world remember santas watching,you may be on the good boy list with me
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It looked ok but not 100% sure, someone has rebuilt it before I could tell that, it did have a scratch on side of piston you could just feel with nail as you went over it, could this effect it? How much is a stroker 29 cc kit? Are Thayer easy to fit?
 
its easy just strip it down bare and clean everythig with brake cleaner spray or petol get it super clean use a old toothbrush,i would think about changing the oil seals and bearings if unsure on there quality plus it makes sense while its all in bits,im not going to get into what head kit to go for as theres to many choices/prices,,,if it was me id just keep it simple a stock 26/29 zenoah headkit probaly half he cost of somthing race ported and it will work realy well with a pipe
 
i also had bogging problems last year with my cy26 in my touring car. as long as i kept my speed up it was ok, however slow down for the tight corners and id have a serious bog when i grabbed throttle. i fought all year, different carb, i sort of masked it with an 8k clutch spring but that wasnt really the answer. i did a compression test and found out i had only 50psi, and found the plating was wearing off the top of the sleeve.

id have another look at the sleeve. im not 100% sure thats what was causing my problem, haven't run the car yet with the new zenoah g230 top end, but im fairly confident thats what it was.
 
Bogging is a result of an air leak usually around the carb. It is most likley a bad gasket. I too had simular problems. i rebuilt the carb and the problem went away. The bogging only happened when you slowed down or stopped. The engine is not getting enough fuel at low speed.​
 
a carb in need of a rebuild could cause your issue but likely not the case. from what ive read and my experience, ide say your topend is done. it is amazing how long the engine will run with the plating worn away at tdc like that but they will do it. you should be able to get into a new head kit for around 100.00 USD. that is including new bearings and seals.
 
no one has mentioned the clutch side crank seal and i next to guarantee you that's what it is, ...just recently i had exactly the same thing and didn't think of it either, new carb same, new top end+plug..same. then the light clicked on...the seal was the culprit.
start your motor, rev it on the stand and spray wd40 into your clutch case, if it the revs drop it's your seal. if the seal has gone i'd also replace your bearing on that side cos it'll be buggered
 
yeah, but if the seal was that bad he would notice a change in the engine at idle, i.e. a fat low needle to compensate or a low idle setting, something. could be the seal though, all things are possible with it setting in front of us to look at with our own eyes, and hear with our ears it would be a lot easier to diagnose, lol.
 
my motor idled fine at 11/4 L but with the idle adjusting screw all the way in so didn't seem like it was sucking air...idled,bogged horribly of idle then would slowly build revs and hit the pipe, that's why i didn't pick it up straight away...and the seal was the worst i've had yet
 
You don't want to run it with any needles all the way in, it will lean seize, it should be tuned to run rich if anything.....any bogging is a sign of a lean mixture
 
Bogging is a sign of an air leak. Not lean settings. The engine will just rev up higher if you set it too lean. the Top end has nothing to do with bogging. Bogging only happens with low speed settings. :lol: Low setting should be 1-1/2 +- 1/4 turn High 1-3/4 +-1/4 turn.
 
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