Another engine
- Thread starter OConnor Racing
- Start date
lol, its interesting to finally hear people are thinking about experimenting with the 115 rod, ive been using mine for years. It does pretty good, i did feel some improvement from the 3mil crank with stuffer blocks, to the 4mil crank with the 115 rod. +the porting changes needed. --sorry, this thread is starting to get jacked!
We've been doing long rods in YZ250 engines since 1994. Back to the rings. They never go past the bottom of the boost port. The intake bridge helps support the piston, not the rings The rings never touch it. Piston skirt wear on the intake side is going to have to be monitored very close and will probably be an issue.
so its friday night... motor running yet? where should we watch for the long rod project are you going to start another thread?
Started working on the engine swap yesterday at 5:00 and didn't finish until 11:00. We broke out the tools, Bud Light and grabbed the bull by the horns. Everything went smooth till Dave “the bolt breaker” snapped my front motor mount bolt. If you want to waste six minutes of your life, watch the vid. All in all, I'm pretty happy but it's got some issues. The Toomy pipe isn't right for this engine. My CPI won't be here until Monday so I'm stuck with it for the weekend. The jetting is also not even close. I'll dial it in today. I didn't want a short torque curve so I was very conservative with the duration of the exhaust port. I'm going to order another piston and cut the front by the exhaust port to see if more duration will work without killing the low end. It's hard to tell what I've got. It was dark, late and I was beat and out of Bud Light so we called it a night. The initial results and ass dyno are telling me this thing is going to kill me once I get her dialed in. More to come later today or tonight.
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Just finished the jetting. The carb is a Mikuni TM 34. Seems like it likes a 280 main. Not sure about the top end yet but the low and mids are killer! Perfect for the woods. Gonna go open her up and break out the ass dyno as soon as Jess gets back.
Jess and I took the Blaster to a place we call the corner track so I could get it out of third gear. The jetting changes made it much better on top but it's still a bit too rich. Awk talked me into getting an Amp-Link and I wanted to test that also. I'm hearing more noise in the bottom than I like. I'm pretty sure it's the crank bearings. I'll change them when I put the 115 rod in. I like the way this engine turned out. It has much more bottom and mid than my old one. The top end feels fine but it's limited by the Toomy pipe. No surprise. I'm not going to change anything until I put the CPI on. The Amp-link is a welcome addition to the suspension. The quad feels much better accelerating out of corners and over rough sections of track. The ass dyno left a stain in my shorts during the testing but that's a good thing.
so it scared the shi!t out of you! haha im glad it went well. good job! im really curious how it will do on the topend with the new pipe. also cant wait to see how the long rod project will turn out. all eyes on you ken!!! haha
If you need a test bed to evaluate the feasability of the CT/LA sleve 240 sonic cylinder, with a 4mm crank and long rod combo... just let me know 
have the cylinder (needs bore) head ready to be recut, 4mm crank and trenched bottom end, I can order the 115 rod tomorrow....
have the cylinder (needs bore) head ready to be recut, 4mm crank and trenched bottom end, I can order the 115 rod tomorrow....
Good to see that baby rippin it up Ken.So where was my invite yesterday?? lol Had to work but did finally get a ride in late afternoon.I needed some stress relief.Can't wait to see the BL blaster in action with the new power plant!!!!!!
If you need a test bed to evaluate the feasability of the CT/LA sleve 240 sonic cylinder, with a 4mm crank and long rod combo... just let me know
that sounds like the thing to do ken...
This build looks sweet can't wait to see more results. Is this the furthest you can push these engines or is there room for more ?
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