Upgrading stock 26cc topend

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Danrox90

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Hi guys I'm wanting to upgrade my stock cy 26 cc topend and I'm wondering what top end its are available, I think it is a 2 bolt engine so would it only match 2 bolt top end kits? I see that most top end kits don't come with the crank but his one does http://www.davesmotors.com/ca486dd312.html why is that? And can I only put cy topend kits on it because it is a cy engine.
Thanks for info im new to all this.
 
Danrox90 said:
Hi guys I'm wanting to upgrade my stock cy 26 cc topend and I'm wondering what top end its are available, I think it is a 2 bolt engine so would it only match 2 bolt top end kits? I see that most top end kits don't come with the crank but his one does http://www.davesmotors.com/ca486dd312.html why is that? And can I only put cy topend kits on it because it is a cy engine.
Thanks for info im new to all this.
Click to expand...

Your stock motor is: 34mm bore + 28mm stroke = 25.4cc
As looker2756 mentioned his kit will be easier to do as you won't have to pull the bottom end apart. The kit he pointed out is basically 2 sizes bigger bore. The kit you were looking at is one size bigger bore and a longer stroke. The end result is they both have the same cc of displacement. The kit you had picked out might have a tiny bit more low end but I doubt you would notice. Go the cheap/easier route.
 
Firstly thanks heaps for you help guys, and what does looker2756 mean by making sure the crankshaft bearings are okay, would I have to take the engine apart before I buy the top end ? And when I upgrade it would I need to break the engine In all over again and would I need to change the stock carb settings?
Thanks heaps
 
Check for play in the bearings by moving the flywheel up and sown & moving the clutch up and down.
Excessive play indicates failing crank shaft bearings, and will need to be addressed if you find it.
Once the top end is replaced, it tunes exactly the same as the 26cc.
Carb settings should very close the the same.
You do not have to take the engine apart before buying the top end kit.
You do want to watch very closely when taking the engine apart, when changing the piston over, to be sure it is re installed the correct way.
It is a pretty straight forward installation, and not real bad to do at all.
Will have to re-set the air gap between the coil and flywheel as well, once finished installing the new head.
Help is just a post away, if needed.
 
quentrm250 said:
Your stock motor is: 34mm bore + 28mm stroke = 25.4cc
As looker2756 mentioned his kit will be easier to do as you won't have to pull the bottom end apart. The kit he pointed out is basically 2 sizes bigger bore. The kit you were looking at is one size bigger bore and a longer stroke. The end result is they both have the same cc of displacement. The kit you had picked out might have a tiny bit more low end but I doubt you would notice. Go the cheap/easier route.
Click to expand...

Smaller bore longer stroke = more torque
Bigger bore shorter stroke = more revs
I'd be going more revs myself as it will give a higher top speed with the same gearing
 
looker2756 said:
http://www.davesmotors.com/chung-ya...bore-up-kit-38mm-skirt-2-bolt-236214036-.html



This is an easier to do kit, and will give you a considerable upgrade in performance.



Will make your engine a 28.5 cc.



Need to make sure the crnkshaft bearings are O.K. before upgrading, or you might need a complete gasket kit, seals, and bearings if needed.
Click to expand...


+1 for this kit as well..... I ordered it and was going to use it but ended up selling it to a buddy on race day after he blew his original top end..... Made a huge difference on his losi.... And we installed it at his pit table..... So pretty easy and quick
 
Have a play with a DREMEL and a 26 head.....I did and this is the outcome.Mines the FG Monster pick up.Both 26cc and tuned pipes.

J;)
 
Last edited by a moderator:
Hey guys it been a while but I've decided that I'm am going to get a top end, but now that I've done some research im not sure which one to get... Last time you recommended me this one http://www.davesmotors.com/chung-ya...bore-up-kit-38mm-skirt-2-bolt-236214036-.html but now I seen this one it is 55$ more but is it worth the money, they claim it an extra half a hp not really sure how much that is but here it is http://www.davesmotors.com/esp-championship-ported-gp290-36mm-kit.html . Which one would be better and is there much difference. And when I did get one do I need to break the new topend in? I want to buy one from DDM preferably ...
Cheers thanks for help in advance
 
They are both bore up kits which means they increase your displacement from 25.4-28.5 however the ESP head is modded and ported. This means he machined room for the larger piston and reshaped the porting giving more hp then the other kit. How much more performance that will give you I have no clue, prob get you revving higher then the other kit I would think..... I'd go with this kit unless your trying to do speed runs or something and even then I seen a fg sportsline with a 30.5cc last week and that thing was quick!

http://www.davesmotors.com/cc253dd308.html
 
I was looking at that one but u have to get a new crank shaft... And it is a bit pricey. Has anyone actually upgraded there top end. And what is everyone else's opinion on which one to get.
Thanks
 
That comes with the +2mm crank. ESP is the way to go. I had a 27.2 full mod prted ESP and it was a beast. Lifted front tires no problem and screamed. I'm now running the same motor but with a OBR head (same 27.2) and unless I used the wrong gasket or something this thing was a dud. Runs hot, doesn't get the front tires airborne and is oddly slow. Now this could be user error as it was my first rebuild but after speaking with a few others that had OBR's I'm not to sure of that. I will be sticking with ESP in the future..... My ESP sat for 7yrs and fired up no problem, lifted tires and was easily 10mph faster then the OBR I have now. Cheap oil was the downfall of that motor.
 
If I was to go esp I would go the other one that I mentioned earlier, the one without the crank... But I'm not sure if I want to pay an extra $55 for the esp over the Chung yang one, as I said before the esp one has an extra half a HP.
Thanks again
 
Also one more thing do I need to put sealant to mend the top end of the engine to the bottom half or just the gasket. By the way I am thinking that I'm going to buy the esp top end kit.
 
Just realised that it will be $200 for the esp because of the aus dollar..... Hahaah I will have to go with the Chung yang... But can someone answer my last question.
Cheers
 
Danrox90 said:
Just realised that it will be $200 for the esp because of the aus dollar..... Hahaah I will have to go with the Chung yang... But can someone answer my last question.
Cheers
Click to expand...
Some people do not use sealant but as a precaution I would. Both of my factory motors had sealant on them.
With your finger smear on a tiny bit of Automotive silicon on both sides of the gasket and then set gasket on and then cylinder.
Use a very thin layer and wipe off any extra along the edges on the interior and exterior of the gasket. You especially do not want anything protruding inside the motor.
 
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