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Author Topic: Squish band question  (Read 14177 times)

Offline Rossy

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Squish band question
« on: November 21, 2017, 03:20:16 am »
Just wondering if I could get any help. I opened my engine up for the first time after having the head re-shaped by a reputable two stroke engine builder here in NZ. The squish angle is cut to 14 degrees which is about what is recommended in the online posts that I've seen, but the width is only cut to 9.5mm which seems a little narrow compared to what I've seen on other lt500r builds that I've seen. Are there any gurus on here that could tell me if that sounds like it's within the ballpark of where it should be? I realize it's probably a wee bit of an open question, but from what I've seen most heads are cut to around 13mm of squish band width which I would have thought was a significant difference.

My motor is an '87 and it has a 40mm carb and boyesen reeds, though I'd like to run a 44mm carb and a vf2 block in the future. The squish is set to 1.1mm, it has 195 degrees of exhaust port duration, an AAEN pipe, a kfx450r air filter with a custom air box, 88.5mm bore and it's all been freshly rebuilt. It's being built as a dune quad so I want it to make good torque higher up in the rpm range

Thanks for any help

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Offline Berthony

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Re: Squish band question
« Reply #1 on: January 23, 2018, 09:02:41 pm »
Where can I learn more and can you recommend me?


Offline Stpltn250r

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Re: Squish band question
« Reply #3 on: January 27, 2018, 09:40:42 am »
Squish is about 40% of your bore. I’d be more worried about msv. I purchased bimotion software and would input all the info. You will need to know the dome rise of your piston. Certain squish velocity numbers are different for different set ups. Drag racing, mx. Do a lot of reading.....


http://www.trx250r.net/forum/engine-transmission/3089-squish-band-width.html#/topics/3089

Offline Iceracer

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Re: Squish band question
« Reply #4 on: January 31, 2018, 01:08:13 pm »
At 195 degree ex you moving away from a Torq motor with a Aaen Pipe and into higher RPM hp. Squish band is also bias toward RPM at this point.

Offline Gaz

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Re: Squish band question
« Reply #5 on: July 27, 2023, 07:08:36 am »
At 195 degree ex you moving away from a Torq motor with a Aaen Pipe and into higher RPM hp. Squish band is also bias toward RPM at this point.

Hey. Do you know what an ideal squish band is (width and angle) for a 196/128 86mm bore motor? Cheers.

Offline Gaz

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Re: Squish band question
« Reply #6 on: July 27, 2023, 07:09:31 am »
Squish is about 40% of your bore. I’d be more worried about msv. I purchased bimotion software and would input all the info. You will need to know the dome rise of your piston. Certain squish velocity numbers are different for different set ups. Drag racing, mx. Do a lot of reading.....


http://www.trx250r.net/forum/engine-transmission/3089-squish-band-width.html#/topics/3089

Hey. Do you know the dome rise for the LT500R Wiseco piston? For this exact purpose. Cheers.

 

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