PSI 890 (Cat 700 based)

Bearcat · Jun 11, 2008

Got curious today

I saw a Cat based PSI 890 cylinder in ebay and noted it was build from good-old 700cc engine. So I'd like to know more info about that engine.

- How reliable was it?
- Hp and torque?
- I'm not sure, seemed there was APVs?
- What pipes should be used?
- etc

I'm not buying any, just curious as I have two mod 700 engines (700cc and 790cc) by myself

mattymac · Jun 11, 2008

All those things did was vibrate! 700,890, and the 950 stroker!

PSI is junk!

Reeb · Jun 11, 2008

Run the idle a little higher, won't vibrate apart.
I've only seen 2 other 700 based BB's that were 890's. Hard on fuel and my 790 wiped em clean.
Not worth it unless it's bought cheap for a spare.

Bearcat · Jun 12, 2008

I just got curious and I'm not buying any

But if 790 beats them... I'm not even curious anymore

But the reason I got curious is the cylinder was modded big time! Whole intake portion was changed, head bolts, exhaust - everything. I didn't even recognize the cylinder at first.

Caveman · Jun 12, 2008

The only thing you could count on is that they would burn down!Hated mine.
Cave

Reeb · Jun 12, 2008

Bearcat said:
I just got curious and I'm not buying any
But if 790 beats them... I'm not even curious anymore

But the reason I got curious is the cylinder was modded big time! Whole intake portion was changed, head bolts, exhaust - everything. I didn't even recognize the cylinder at first.

That kinda sounds cool enough to ask.....got pictures?

Bearcat · Jun 13, 2008

Here's a link:
http://cgi.ebay.com/ebaymotors/Part...adiZ2815QQcmdZViewItem?hash=item180252567784&

JPM · Jun 14, 2008

that is just a standard 890 psi cyl reed cyl. It was made to take 700 polaris reeds which were the largest available at the time, it was a very well designed cyl that took advantage of the shape of the 700 cat case. It is in all a better cylender than the 1200 was. watched them run as twins tripples, 890 and 950 and it was a big improvement over the stock based cyl stuff, the bad rap came from the ignition in the new version of the 700. Once and old ignition was put in they ran very well. like any psi motor in the right hands they worked well. JPM

Reeb · Jun 15, 2008

Maybe that was the problem with the 890's I saw, both stock based cylinders. I showed that link to my dad and since he built up my motor he noticed a bunch of things straight away. Said he'd like to have em in his hands for some comparisons. haha. My 790 is off a stock cylinder design too but with lots of shaping and reshaping of a lot of internals. Oldstyle ignition, PSI Modblasters, and some honkin roundslides. I was about 800rpm low when I was figuring out my clutching with some new components. Still highmarking every new 800 and it was almost toe to toe with a M1000. Chassis isn't so stock though. I'm hppy on it for another year, then it's a Nytro or a IQR project next.

Bearcat · Jun 15, 2008

Your dad isn't only one who would like to do some comparsions

I'd pleasingly would like to measure those too. The finishing looks really good (even pics are small). Those must have been very prizey things some day.

I agree 790 is hard too. Even my engine isn't properly tuned yet, it did show some storm signs for my mod rotax 800 pals

JPM · Jun 17, 2008

Yes they were pricey new they were 1200$ american just for the cyls new. Now they are more affordable used and can be found once and a while. They were an overlooked setup because of the timing of their introduction, but will still put a hurt on lots of so called newer tech.

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PSI 890 (Cat 700 based)

Bearcat

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mattymac

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Reeb

Modding mini's

Bearcat

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Caveman

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Reeb

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Bearcat

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JPM

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Reeb

Modding mini's

Bearcat

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JPM

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