I had a reputable guy build my motor a while ago. Finally got it legal and took it for a longer ride and when I got back home I noticed some top end knocking. I maybe have 3-4 tanks of gas run through it, so not that many miles on the bike yet. I did have the timing slip, so I reset the timing on it. Just looking for feedback on where to start. It's super disappointing as I haven't even got to enjoy the bike and I'm afraid I'm already troubleshooting problems. My builder has not gotten back to me, so I think he may be MIA. Thanks for any feedback you guys could give me.
https://youtube.com/shorts/APU7rufTpWY?feature=share (https://youtube.com/shorts/APU7rufTpWY?feature=share)
What ratio premix are you using?
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16oz to 5 gallons of gas, 40:1.
Ok. That should be alright as long as there is very little full throttle use. The pump kicks out about 20:1 after the 3/4 throttle position.
Sounds like a partial seizure to me. Could have been an air leak too...
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If you are sure the noise is from the top end, I would do a leakdown test first to check for leaks. Check what the plugs look like and then pull the head and take a look inside.
almost sounds like a small end bearing, but could be a partially collapsed skirt.. id pull the cyls & see whats up. :twocents:
Clean build. I would inspect everything. When he built your engine, was it both the top and bottom end? What did he replace?
Thanks guys. You all know my builder, just don't want to throw him under the bus for something that happens on a crappy day. He built it from the ground up so every piece was touched, replaced, ported, upgraded, new. I know he has been MIA, but he typically would get back to me if I called or texted him, hoping he is alright.
Make sure you check squish clearance. Could be as simple as a wrong thickness head gasket.
Piston slap maybe pull the pipes and take a quick look inside there.
Agree with the others and lift the cylinders off, then post some pictures if you need help figuring out what's up.
Sounds like what mine did when it ran on little oil. Pull heads and look.
Thanks all. I'll pull them in the next few weeks and update. Appreciate this community, wouldn't have gotten the bike done without everyone here.
Wow. Riding season starting up in Florida. Just use a large portion of patience and get it right before setting yourself back for the summer.
Quote from: Joshua on March 15, 2022, 12:03:56 PM
Thanks all. I'll pull them in the next few weeks and update. Appreciate this community, wouldn't have gotten the bike done without everyone here.
Wow, you have a lot of patience. I would have had my motor apart within minutes of getting it home. I would just have to know what went wrong or it would bug the s**t outa me.
this.
whos almost burned their hand on a piston pulling it out.... :whistle: :patriot:
Quote from: Joshua on March 13, 2022, 08:35:18 PM
16oz to 5 gallons of gas, 40:1.
35ml of 2T per 1000ml of gas is fine for a lightly ported RD ? :umm:
Quote from: m in sc on March 15, 2022, 02:28:15 PM
this.
whos almost burned their hand on a piston pulling it out.... :whistle: :patriot:
Definitely been burned by exhaust and sparkplugs more than once.
Quote from: 2t Fan on March 15, 2022, 03:44:03 PM
Quote from: Joshua on March 13, 2022, 08:35:18 PM
16oz to 5 gallons of gas, 40:1.
35ml of 2T per 1000ml of gas is fine for a lightly ported RD ? :umm:
yes, typically its fine. it wont cause a seizure, that's for sure. I used to run my high strung yz on that ratio no issues.
Thanks all . . . Yes, I'm patient or made to be patient. It took me almost 5 years to complete this project. . .lol. Actually, I just sold my warehouse and changed careers. This past year has been a year of simplifying, sadly selling off way too much I just don't have room to store anymore. Next project I picked up is an RZ350 I'm dying to get to. . . . and it's sitting there staring at me . . .
Either way, I'll keep you guys updated, should have it apart in a week or two.
Nice looking bike, fenders might come in handy when it rains.
Welp, here is my stupidity. Now that I've had some time to think, I believe when I lost my timing, I heated up the right cylinder, which may have caused some damage that I didn't catch. Then on my longer ride I did the rest. Great learning experience, sucks for me. Lol.
Couple questions so I'm not spinning my wheels here.
1– will I need piston, rings, rebore/hone. Is there anything else.
2– who can I send the work to? I'm in florida, so I guess shipping would be fine.
3– is there anything I should be concerned with other than the obvious.
Thanks for all the encouragement here. Many times my first time through things I overthink and it freezes me to not just jump in and get it done. I'm learning . . .
That doesn't look bad at all. You should be able to clean the cylinder up with muratic acid and then just a new piston.
Could you post more pics of both pistons and what do you mean by it lost timing?
I've got the vape ignition, flywheel slipped.
I have to pull the pistons off. Really just looks like one cylinder is down but I feel I should just replace both. I'm nervous when my timing slipped it caused some weakness in rings/pistons.
if timing slips on the vape setup, it would normally retard the timing. As the flywheel would slip backwards after firing the cylinder.
One thing to note when installing the vape. Heat the center taper of the vape flywheel with a heat-gun for like 60 seconds or so and then install it as quickly as you can. Give it a tappy-tap-tap with a plastic mallet and then install the bolt with extra thick washer from economy cycle. The taper is what sets the flywheel, but the extra few ft-lb's clamping down on it never hurts.
I did this when I set the timing, I also lapped it before I reinstalled it. . . .
do not lap it. theres a 1/2 degree difference which is what gives the interference.
Make sure that longer bolt isn't bottoming out (it's been reported a few times), Add washers if it does. 18-20 ft/lbs of torque on the bolt.
Got it, Chuck got back to me, so I'm in good hands. I sent him some detailed pics and he suggested sending him the barrels, then once I get things broken in again I'll go and hang out and double check everything on the bike. Every time I go up there he is a wealth of knowledge. May even have some parts he needs from my left over pieces to keep one of you guys on the road. Things are working out. Just have to be patient I guess. Lol.
Very cool! We all miss him being here.
As we all know life can get in the way. Soon to spend some money on the Daytona and hoping I can get him involved.
Looking at the amount of blow by, that piston looks like it went thru 100 fuel tanks.
Did you tune the bike yourself?