sparky 25

Im just after spending a heap of money on upgrades to run my km baja on sand,

now the engine has decided to crap itself, it had only had about 2-3 gallon on it,

it was running great when all of a shot it just stopped,

i tried starting it again but it was down on compression and was making grinding noises so i went home to tear it down,

i originally though that the torn oilseal had let sand in but that was on the clutch side and i have a tgn enclosed clutch housing,
the oilseal on the pullstart side was in perfect condition,

i then pulled the piston from the conrod and the piston bearing case fell to a thousand pieces, so thats what wrecked the engine

when i split the crank case apart the crank bearings were running extremly rough as was the bigend bearing,

i want a cheap reliable replacement engine and was needing to know if the hpi 26cc was a good engine.

DarkFire989

Get a zenoah 26cc. You cant go wrong with a zenoah.

SAVAGEJIM

These KM engines are sub-standard. That is one of the reasons why these RCs are able to be sold at very cheap prices. Just as all of the experienced Australian KM fans have done, yes, going to a better engine is best. If you read through you KM thread you usually hang out in, you will see that the Australian fans in many cases rip out the KM engine in favor for engines that will last and be way more trouble free. Some of them actually rip out the KM engine as soon as they get their brand new KM in the mail and never use the KM engine due to its problems.

Look for the posts by the member named Beckiesbajas and he gives great engine suggestions to replace the stock engine. He has extensive direct and firsthand experience with KM RCs and speaks from that experience truthfully. His suggestions will not let you down.
http://www.rcuniverse.com/forum/m_7249314/tm.htm

As for cheap reliable engine, you should look an CY engines. The HPI 26cc Fuelie is really a CY engine. So if you can find 26cc CY engine somewhere, a brand new one will cost less than $200 USD.
Alternatively, is you want more reliability and a tad more power, you can get a Zenoah G270 4bolt 26cc engine for about $250. And that is a great engine for the price; come to think of it, there are NITRO engines that cost more than $300 USD! So, even that $250 really is not bad at all. And if you shop around, you can get discounts to reduce that $250.

sparky 25

Thanks for your reply,

i have been looking at the zenoahs earlier but they are very pricey

i looked for the cy 26cc and just scored a new in box hpi cy 26cc fuelie on ebay for just over $100,

the shipping ain`t too bad either at just under $35 to ireland from the usa

can`t wait for the new engine to get here to get going again.

46u

My Feedback: (3)

Sound normal for a KM engine.

da mad maori

a cy isnt as good as a zen but ALOT better than a km....
youll be happy with a cy

BigGrump

Not for me, however, I actually have experience with a KM engine. I put three gallons through mine then upgraded the top end with a zenoah 26, just for the fun of it. Left the bottom end alone. Never had any trouble for another two gallons when I got a good deal on a cy29.

When I took the KM apart to change the top end, I found nothing wrong with the piston, cylinder or wrist pin bearing.

Sure some will fail, but not all. Funny how the cy29 is working out so well for me and all I read from some people is how bad the piston and cylinder is in it. Simply not true from my actual experience.

Dennis

46u

My Feedback: (3)

CY has improved there cylinder plating and not having the problems they use to with the GP290. There is a old and newer version of the GP290 engine. The older one had a 38mm skirt where the newer ones have a 40mm skirt where the cylinder goes in to the case. Yes some have great luck with the KM engines but you read more about them failing then CY or Zen. Coarse there are some that can mess up and anvil with a rubber hammer. [X(]

BigGrump

That is very well stated. I fully agree that the KM engine fail more than the CY or Zen from what we read. But......... I am also confident there are more KM engines running around trouble free than what these forums would indicate.

I just wish more people would deal with the clones more factually than is noted. They all evolve over time to something different than what is initially purchased.

Dennis

srt10

My Feedback: (20)

I agree, the KM motors are clones of the CY and the 23cc motor has a cheap piston bearing and causes failure fast.. 2-3 tanks

I will be getting a CY motor soon!

dc2 man

the cy and zenoah are very similar well the 23 & 26cc anyway other than them totally differnt......a clone of a clone is verging on dodgy really isnt it.......

bad luck though after 3tanks....sand prob got in there somehow.....#

bloody sand is so hard to keep out............

TheFgMan01

Yeah my Marder is atleast 5 years old and i have the Zen26, it's still strokin strong man. not a problem, only replaced the cyclinder gasket.

my FG H2 has a cy29, great motor as well and puts out crazy power with my top-end ddm pipe... both of mine run ddm pipes

srt10

My Feedback: (20)

no sand bad piston bearing..
put a 27cc top end kit on it, then the case cracked!

TheFgMan01

Oh and stay waaaaay away from those CY engines that have the roundish cylinder heads?!? the one you can change out the compresion domes ya know?? JUNK.. I hade one for 2-3 tanks and it crapped out. Great power for 2-3 tanks though

srt10

My Feedback: (20)

Thanks for the input! I've thought about one of them cuz they looks so cool.

But this is what I'm thinking of getting
http://www.davesmotors.com/s.nl/c.88...t.A/id.4941/.f

TheFgMan01

^^ Thats a good choice! "Earth Surfer" is really good! Wow CY has a 31cc now.. i havent been on these boards for awhile
.. yea as far as that other engine. they do look great, i picked the silver finish cylinder head. But the looks last longer then the engine so.. Leav that motor alone seriously

46u

My Feedback: (3)

[/quote]

Wow CY has a 31cc now.. i havent been on these boards for awhile
..
[/quote]

CY has had this engine for a while. It is really 30.5cc with a bore of 36mm and a plus 2= 30mm stroke. Same bore as the GP290. I personally like the stock stroke as with a stroker your acceleration is not as good or your top RPM (top speed).

I have a new set of cases, stock crank and flywheel I picked up cheap. I have a race ported GP290 top end that should be here today with a set of DS porting templates. I will port the case and match the head and cases. Only hold up is my rotary tool died and I have to get a new one. The GP290 is really a 28.5cc. DS porting template.
http://www.davesmotors.com/s.nl/c.88...t.A/id.1173/.f

ZEN is finally coming out with a 36mm bore top end for there 4 bolt engines. No they are not going to make a whole engine just offer it as a add on. They are not going to make them for 2 bolt.

TheFgMan01

That is pretty cool, I didnt know those porting guides were out LOL!! i've been wanting a race ported head for awhile. But i going to look into those so i can do he case as well.. im curious of the outcome in performance.. Good luck with that..
Are you going to start a thread with pic's when you start the tear down? That'll be a good one

srt10

My Feedback: (20)

A stroker motor will pull hard.. and bigger does not always mean lower revs..

TheFgMan01

Thats i want to do my stock CY29 that way!! it's fast but i wanna see what it'll do with a higher rpm
ofcoarse its dosent rev like my 26 does

46u

My Feedback: (3)

I have been a Harley mechanic for over 37 years and have stroked many a engine. I have see what a stoker will do in real time as well as on a dyno. A stroker will have more torque but will rev slower with less top RPM.

46u

My Feedback: (3)

A CY GP290 running a 36mm bore with the stock 28mm stroke should rev just as high as a .26 but do to the bigger bore will have better torque. Will not have the torque of a stroker but more then a stock .26.

srt10

My Feedback: (20)

Well that's a HD for ya!
No small block car in my area could touch my big block Firebird on the street. I used to street race 20years ago and never lost to a higher reving small block
My big block would rev to 6500rpm and was going to change rods to get to 8000rpm, but I never needed the extra revs
these buggies weight alot and more torque is always welcome to make rcing more fun, and a stroker is one fast way to get the job done

46u

My Feedback: (3)

As long as it makes you happy is all that matters.

srt10

My Feedback: (20)

I miss my big block