mopar1rules
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Posts posted by mopar1rules
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Looking to buy 2 vitos .020" thick base gaskets. Need 1 for sure. Please pm me.
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Got a OEM crank that needs to be rebuilt
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The only thing I like about the single ring piston is that you can add a boost port to the piston where as a dual ring piston has no room to properly place a boost port. I thought about modifying a 68X54 cheetah into a 68X58 but thought the port timings would get a little too wild with the transfers.
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I never really had a problem adjusting rotax power valves with spring changes. im o e of those guys that can't have enough power. Right now I want a NOTICEABLE increase in power from my 4mil ported setup. So, the cubs eat up pistons but the cheetahs don't?? If this is true, its probably from the large intake window area?? Yeah the best form of a actuating a power valve, is with a cable from a servo motor, that gets its signal from a TPS and CDI box. That way is so consistent, but a little more complex to hookup. I guess I will have to look back into the cheetahs then, seeing as some others like how strong their motors are. I wish the cheetahs with power valves had a 68 X 58 option on the CP industries website.
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Yeah I guess. The trails I ride are open and have many long straights. Which is why I didn't think it would be an issue with the cubs high exhaust timing and slight lack of low end.
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So, you use a keihin main jet to adjust how and when the power valves open? Sounds like a shitty setup to me. I assumed they worked like the exhaust valves found on the Polaris and Ski-doo sleds. I think I will stick to the cub and give it high comp for better bottom end.
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That's kinda what I was thinking with the stock cylinders and big bore sleeves...... nor being able to flow properly for 68mm+ bore sizes. I feel the transfer runners on the stock cylinders aren't up to the challenge. I guess I will stray from the OEM cylinder big bore idea then. I thought I remember reading somewhere that the cheetah cubs with PV's were expensive to setup right and dial in, to make power and that the non PV cubs made hp more easily??? Any truth to that? I like the idea of the power valve, so I can have low end and top end.
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Do the cheetahs with power valves have the same port timings as the cubs? Or do they have higher exhaust port timings, due to them having power valves? The reason im not really looking into serval cylinders, is because I thought I read on here that they dont take well to high compression and some of the higher rpm pipes?? I thought people weren't able to get them to run like ported cubs??
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Stock stroke port? Send pics to 920 905 0969
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Don't know which cylinders I should go with for trail riding and playing around in fields etc. Cheetah cub 421 (68mm bore +4mil stroke), cheetah with power valves, or stock cylinders with big bore sleeves. I currently have stock cylinders that are ported for the 4mil with 4mil long rod crank, 15:1 comp, vforce2 reeds, timing +4, r2 pipes, bored stock carbs, airbox modded, and case ported. Just looking for some more hp. I guess the cheetah with power valves use cr250 reeds while the cub uses the stock reeds. Which setups have you guys used and had good luck with? Thanks.
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i'd go with the vitos 4 mill long rod crank
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I will add that I as well have been having good luck with the vitos 4mil long rod crank and that's what I would stick to.
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who the hell did the work?
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And make sure the new domes don't have an abnormally wide squish band. Don't need anything over 55-60% on pump gas imo.
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That "custom" dome is garbage. That's the problem. Get normal hemispherical domes that will yield you a 12.2:1-12:1 comp ratio and you will be fine with 93 octane and .050-.055 squish. You will also need a squish angle that's 2deg more positive than your 573 series piston crown angle.
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I can tell from your intake pic that you ate using the race logic template
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But is it possible to get a 7.5:1 ratio and 175 psi on a banshee motor?
Anything is possible
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alot more than just compression determines whether or not you can run pump gas. 7.5:1 compression ratio and 175psi could safely run 93 octane
One of the best replays to a "what octane do I run" question. Timing also plays a role in what octane fuel needed. Its not based off of "cranking psi".......don't know why everyone keeps thinking that.
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I never had a problem with stock needles. I even ran the stock needles in a set of mikuni tm28's with great success.
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Just keep it stock if that is your response
No kidding
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Hey guys im new here but my buddy just got a shee and someone has cleaned up the ports and sharpened the bottom of the transfers but it just doesnt seem to run right? it has nooo low end you have to rap it up quite a bit any ideas on whats wrong?
Whoops.....don't know what I did there. Lol. Anyhow, to answer your question, they could have raised the exhaust a bunch and have the blow down something ridiculous like 37-38 deg or something, or they lowered the exhaust port floor and now have free porting going on, or the transfer timing all jazzed up, etc. It could be a number of things and without looking at it with my own eyes and measuring things, its just a guessing game. Pm me and we can talk further. Maybe I can fix them for you, if there is material left and you want to send them to me.
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Hey guys im new here but my buddy just got a shee and someone has cleaned up the ports and sharpened the bottom of the transfers but it just doesnt seem to run right? it has nooo low end you have to rap it up quite a bit any ideas on whats wrong?
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I got it out on Sunday for a couple of hours. There wasn't enough tread to run ice screws so I didn't bother. I went out with 3 of my friends and there 4 strokes. It was 18 degrees out and none of there bikes started. Mine did, and I pull started the first guy to get them going. Traction on the lake sucked. The bike hits the power band and spins like crazy. It was too hard to tell how it was performing. I ran it for maybe a total of an hour just to get some time on it. We did ride on a couple of islands so I was able to feel how it rode and it rode really nice. When I got home I did a small street run up to 3rd gear and let off. I don't want to piss off my neighbors. Its boggy till the power band comes on, when it does it pulls really hard, feels like a turbo kicking in.
You say its boggy till the power band kicks in?? If you used the Race Logic stage 3 porting templates and never touched the transfers, that's the reason. Your blow down time is too long. You will be at 35-36 deg and you will want around 30 deg if running pump gas and you can get away with 32 deg if high comp and race gas. With a shorter blow down period and staggered transfer opening, you will have much more low end, wider power band, and the power will come on sooner, with the same strong top end as before.
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What are the duration specs on these "drag" cylinders? Just want to see if they are way to high for me.
What's the max psi compression for 91-0ct pump gas @sea level?
in Banshee Repairs and Mods
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Agreed....i ran a stock head that i milled .030" off on my stock stroke setup and i run on a stock head on my 4mil too. It's cut for the additional stroke of course. I love how it never leaks like my "poor design" cool head did. Don't know why people don't like the stock head. Just because its a stock part, doesn't make it bad. And just because a part is aftermarket, doesn't make it good or better than a OEM part. To the original poster, you could have your stock head cut for cheap and pick up some power.