Hi I'm Randall, I'm new here and I need some help.
- Thread starter pumphandlerandall
- Start date
as soon as I posted I finally figured it out. I have the 70 vertical minarelli smolik performance cnc platform. Engine had about 3 hours of run time and many hot and cold cycles like I do with any other engine and never had any issues, but Was doing about 48-50 mph @ 8800ish on my first harder pull during tuning and hit a split second seize that locked my back wheel up instantly causing me to fishtail for about 300 ft, luckily I kept a bike up right the entire time it was definitely a god saved my ass moment . Definitely Scary. Pulled it over, checked everything over and it fired right back up and I rode her home gently. Once I got home I took it apart and inspected and I got some glazing down the sides of my sleeve. Nothing to the fingernail, and this is a custom built engine by him and I was not certain of what type of piston it took. But I'm telling you This thing is an absolute monster . I was able to get a hold of him and he sent me the link for the piston, and the correct honing tool. This will be my first time doing this, I've messed with two strokes for a very long time and never ever had a seizure. Guess I'm gonna learn
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I've never had one of those... But it's a common problem from what I've read... A colder plug and richer oil mix is something to think about also the ring end gaps could be opened up and a light sanding off the piston above the top ring... Honing will help the cylinder hold oil... I would go rich on the jets as well... Maybe retard the timing... Those engines are going to need every trick in the book to not overheat without the fan to cool them like there should be
I'm running br8hs by his recommendation. I love the engine it's insane . it's my fault it happened ultimately, but now I know. And I like the challenge of learning new things so I'll become very familiar with it until I learn everything about it. I've never owned an engine like this , only reg China dolls so it's a new learning experience. And what exactly do you mean by opening the rings and sanding the piston? I'm assuming that helps hold oil at high rpm?
Thank you, yeah she's my dream build . Everything pretty much except forks and head set were upgraded . I've invested quite a nice chunk o change in her because I wanted the best , and I knew there would be some learning that came along with stepping up to an engine like this so I'm willing to learn whatever it takes to until I get it perfect. . I had RMH build the minarelli racing pipe for me, and had smolik build the engine. And has a real Mikuni vm20 carburetor.
Those pipes are top notch man. Worth every penny. The power band on this one is straight wicked
I would be curious to how much clearance there is between the cylinder and piston cold then double it just at the top... The grove the top ring rides could be opened up a little also... You may loose a little of compression until it warms up but loose the sizing... Running rich might loose some power and foul a colder '9' plug but help also... I'm talking about just the top diameter of the piston above the top ring the bottom ring and everything else kept at the spec. You can open up the cylinder above where the top ring lands a little bit also to accommodate the swelling...
I moved the clip up and it got a lil better, but that was before I seized yesterday so I moved it back, I'm scared of running it lean. I feel like the main jet size caused the seize, if it's responsible for full throttle I assume it was too lean. I figured 280 would be plenty rich considering he told me 210-280 would be my jet range . I went rich of course, now I have a 300 in there and it didn't seem to make much difference but I know it's gotta be a lil richer right?
Yeah I just pulled the plug and it's definitely richer, It was slightly oily where before it was dry. . Today is my off day and it's pretty nice outside so I'm trying to do a little tuning, since the cylinder/ piston already messed up anyways and I got new ones coming. I figured in the meantime I could at least try and narrow down my tuning so that this doesn't happen again.
just the mid is acting up , other than , she is a monster and idles beautifully.