Howdy folks,
After multiple failed attempts to get a good jetting on my RZ, I hesitantly took it to a shop who found low compression and advised a top-end rebuild. :bang:
I see numerous choices out there but wanted to get opinion from y'all. Any advice is highly appreciated.
I'm not after every hp gain but would be doing spririted riding in mountains and certainly would want it to sound nice.
Thanks!
Lions and tigers and bears, oh, my! So many choices here. Assuming you have room left in the liners, you could just bore to the next size, or bore to the maximum possible, or replace the cylinders with Athenas or the like, and/or add a stroked crank to any of the above.
1) what do you want to end up with?
2) what's your budget?
3) how much additional maintenance are you happy with?
You're correct, too many choices. Thanks for your response.
The current ones are at 64.25 mm if my memory serves me so I could go to the next size up - 64.50 mm. To answer your questions:
1. I'd want to get a reliable motor.
2. $800 including labor, maybe I'm stretching here.
3. Im okay with regular DIY type maintenance.
What piston kit do I go for wiseco, pro-x, etc ?
Pro-x. Keep it stock, overbore only.
Clean power valves as well and run it.
Given your answers, Matt's spot on. A quality bore job and a conscientious assembly will get you miles of smiles.
I concur.
Thank you guys! I'll keep it posted on how it goes.
Pro-X and 64.5 mm on mine, that mnein rebuilt. Still stock.
Nice and strong, (before the electrical issues). I have much appreciation for YPVS.
So the shop said even with piston rings or the complete top-end rebuild they aren't confident that the issue can be fixed until the motor is split and they just don't have the expertise to do it. They don't have any recommendations either :disappointed:
Issue is low compression - 42 as opposed to 150 as they tested, they're amazed that we even have combustion with that low of a number. Also a bubble of smoke although starts in few kicks each time.
I'm in Colorado and need an experience builder and punctual (preferably in-state) but willing to work out of state. Does anyone have a recommendation of good ones? I see https://herrjugsracing.com/ although shipping can get expensive.
Have you checked the compression yourself?
Find a used Mac tools or Snapon compression tester on ebay and check. Not calling your shop a liar but if you want to play along with old 2 strokes, some stuff is best done in house.
Even if you have an air leak, it won't impact compression numbers. It's likely you have more problems, but it sounds like that shop won't do anything unless it's everything and they don't have confidence. Seems like they don't want to be married to it unless they've gone through it all themselves.
Also, don't take any of this the wrong way, we all make mistakes (especially me) and need teaching. If you weren't opposed to shipping the motor I'd do it for you.
Thanks for your reply.
I haven't checked myself but I will once I get it home this weekend. You stated - " It's likely you have more problems", is there anything else I should check on?
Much appreciate your time and I'm happy to learn.
You can compare the compression of the 2 cylinders by just pushing the kickstart lever with your hand. You would feel the difference between 42 and 150.
Sure, there's typically a few unknowns when working on motors. One of which is the crank seals, and on your case the coolant system as well.
Those both can be tested fairly easily with the right tools.
Pressure testing the motor requires a trip to the plumbing store and a few things from Amazon.
Coolant pressure testing requires a coolant pressure tester, easily acquired from Hobo Freight.
That's all I meant. Aside from ignition and fuel potentials, you can and should rule out the motors ability to hold pressure in the crankcase and coolant system before and after disassembly.
So I got multiple threads at this time to chase but here's what I have been upto:
1. Took out reeds, they seem fine. No residue or any funky stuff.
2. My compression test shows 84 and 85 on left and right cylinders.
3. Took out clutch cover and I see the oil seal behind the primary gear put in reverse position. Shouldn't the numbers face outward?
Attaching pictures for reference.
Pic 1 & 2: Inside and outside of the reeds.
Pic 3 & 4: Clutch cover opened and eek of the oil seal behind primary gear.
Pic 5 & 6: Oil seal from either sides.
Can someone school me on how this seal is supposed to be, please?
castelations (nubs) always go towards the bearing (in).
Thanks Mike, that makes sense. I'll keep trying things others mentioned.