What should I check on a engine that lost some power

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Gee

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Long story. The cy26 that came on the 5b ss kit had some flaking issues on the cylinder wall which made running it impossible. I bought a Zenoha 270 to run while dealing w/ HPI. They sent a new head but I bought a a 36mm Big Bore Kit. I had been running the Zenoha all that time so the engine in question really hasn’t had a lot of use. The summer was a blur and I am not sure exactly when I got around to installing the BB kit and using the engine. It didn’t seem much more then a month of use. It was running well and then seemed to start loosing the power it had. I had it a little rich as far as mixture goes. I tinkered with it a bit but it was summer and I just wanted to get back at it. I reinstalled the 270 back on and put the cy26 on the shelf.


I am going to pull it back out and give it another go. I will be using the 813 carb that is on the 270 now. I have ordered a rebuilt kit for the other 813 I had on it and the Zenoha but a couple months ago bought a new one.


I also have in the cart the two bearing for it from fast eddy. I’ve never replaced the bearing on an engine so total newb question coming. Are these all I need or are there other bearing also? http://shopping.netsuite.com/s.nl/c.885035/it.A/id.1275/.f


This is the page at DDM that has the bearing on it for the cy23/cy26 engines.


http://shopping.netsuite.com/s.nl/c.885035/n.1/sc.12/category.27893/.f?range=49,96,130


I am hoping that the 813 carb that is on it just got dirty and it will run good with this newer 813 on it. If I get this one running good I can use it on the Rampage when it arrive and keep the new engine on the bench for a while.


Any suggestions as to what to look into for the loss of power?


What would you say the average life span of a big bore kit is (if properly maintained).


This is the big bore kit I put on it.


http://shopping.netsuite.com/s.nl/c.885035/n.1/it.A/id.4166/.f


Thanks for the help again.


When I cover the intake and exhaust holes and spin the flywheel it doesn't seem to have much compression or notching like the other engine. Would that indicate it is time for a new head?
 
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As long as you maintained your filter and didn't suck in dirt you should be able to get at least two piston ring changes out of an engine before the head needs to get replaced. Most guys take it further to 3 or 4 rings. I typically pull my cylinder every 5 tanks and check the walls for damage. After about 15 tanks I replace the ring. You can go ALOT further than 15 tanks, however, rings are so cheap it's good prevenative maintainance to replace them.


Typically slowely degrading performance is a sign of compression loss due to poor ring/cylinder mating. I would check the cylinder walls for scratches or damage. If it looks good, replace the ring, reset the carb needles, and run it again. Also, some guys make the mistake of pinning poor low end performance on the engine when it's really the clutch spring. Clutch springs just flat out do not last. Eventually they soften and will bog your low end like crazy. If you notice that the car runs good cold but after a few minutes it bogs you have a weak clutch spring that needs to be replaced.


One of the biggest bangs for the buck, in my opinion, is a 4 shoe Lauterbacher or Elcon clutch system. I've had my Lauterbacher for 2 years and 4 cars and the shoes still haven't worn noticably. I adjusted the clutch the first day I got the clutch to around an 8k engagement and have not touched it since. The adjustment stays rock solid. I paid $129 for it and I gaurantee I would have replaced at least 10 stock shoes by now.
 
DemonRC said:
As long as you maintained your filter and didn't suck in dirt you should be able to get at least two piston ring changes out of an engine before the head needs to get replaced. Most guys take it further to 3 or 4 rings. I typically pull my cylinder every 5 tanks and check the walls for damage. After about 15 tanks I replace the ring. You can go ALOT further than 15 tanks, however, rings are so cheap it's good prevenative maintainance to replace them.
Typically slowely degrading performance is a sign of compression loss due to poor ring/cylinder mating. I would check the cylinder walls for scratches or damage. If it looks good, replace the ring, reset the carb needles, and run it again. Also, some guys make the mistake of pinning poor low end performance on the engine when it's really the clutch spring. Clutch springs just flat out do not last. Eventually they soften and will bog your low end like crazy. If you notice that the car runs good cold but after a few minutes it bogs you have a weak clutch spring that needs to be replaced.


One of the biggest bangs for the buck, in my opinion, is a 4 shoe Lauterbacher or Elcon clutch system. I've had my Lauterbacher for 2 years and 4 cars and the shoes still haven't worn noticably. I adjusted the clutch the first day I got the clutch to around an 8k engagement and have not touched it since. The adjustment stays rock solid. I paid $129 for it and I gaurantee I would have replaced at least 10 stock shoes by now.
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Thanks Catchaser...That's some great information... :cool: :D :)
 
If you covered the intake,exhaust, and the spark plug hole, and pulled the pullstart and it seemed low compression then it sounds to me like the piston ring is not doing its job, I agree I would completely break down the motor, replace all gaskets, put your bearings in, and the new bore-up kit, once the motors done then you can replace the clutch spring or the entire clutch.
 
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That's is some great information. Honestly I wasn't even thinking about the piston ring, was already pricing another big bore kit. Must be a nitro flashback or something. I checked the head bolts and they were good.


I put an order in yesterday at DDM but wasn't sure what to do with the engine. I got another order going now though. I just love getting new parts in the mail. Got the CY 36mm piston ring, a bearing set, gasket set, and oil seal set. I like the idea of the Laugterbacher 4 shoe clutch but have already emptied the play budget. This may be getting close to being the new record for money spent on the hobby in a single month.


I watched the Fast Eddy rebuild videos so I think I will be good to go when the parts show up. I was able to get the flywheel off before with a 3 jaw type puller. Thought about getting a better puller (one made for these engines) but the price is hard to swallow. Thanks again for the input.
 
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I got the parts in for the engine. Going to put in new bearings and seals and install the new piston ring. Is there any kind of beak in needed after installing the parts I am in the motor?


I found the sticky at HBF that shows how to pull the flywheel. http://www.hpibajaforum.com/forum/showthread.php?t=95647


Seemed a bit safer then the way I did it with the 3 jaw puller I had. I am going to go back through the sections of the fast eddy video that apply but if you have any quick tips. I would like to hear them. Thanks again for you guys help.


Looks like I will need to do some flywheel balancing due to a couple fins are missing on this one. I may just pull the flywheel of the CY26 coming in on the MT and buy a replacement for it later.
 
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DemonRC said:
As long as you maintained your filter and didn't suck in dirt you should be able to get at least two piston ring changes out of an engine before the head needs to get replaced. Most guys take it further to 3 or 4 rings. I typically pull my cylinder every 5 tanks and check the walls for damage. After about 15 tanks I replace the ring. You can go ALOT further than 15 tanks, however, rings are so cheap it's good prevenative maintainance to replace them.
Typically slowely degrading performance is a sign of compression loss due to poor ring/cylinder mating. I would check the cylinder walls for scratches or damage. If it looks good, replace the ring, reset the carb needles, and run it again. Also, some guys make the mistake of pinning poor low end performance on the engine when it's really the clutch spring. Clutch springs just flat out do not last. Eventually they soften and will bog your low end like crazy. If you notice that the car runs good cold but after a few minutes it bogs you have a weak clutch spring that needs to be replaced.


One of the biggest bangs for the buck, in my opinion, is a 4 shoe Lauterbacher or Elcon clutch system. I've had my Lauterbacher for 2 years and 4 cars and the shoes still haven't worn noticably. I adjusted the clutch the first day I got the clutch to around an 8k engagement and have not touched it since. The adjustment stays rock solid. I paid $129 for it and I gaurantee I would have replaced at least 10 stock shoes by now.
Click to expand...
Question about the rings, i'm getting the Maverick Blackout (europe Rampage MT) with the 30.5cc enginge like the V3 Pro could you point me in the right diredtion for these Piston rings?


Regards
 
Thanks for the help on this. I installed the new ring in and got the power back from the engine.
 
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