Old school, big power

[mattymac]

Also, the Jaws pipes fit really well after getting them installed with the motor finally bolted in for the last time the only thing needed (besides a taller hood) was to make some clearance for the MAG pipe in how it wraps around by the center cylinder APV cap, making a new hole out the belly pan for the same MAG cylinder silencer, (the PTO and Center silencers exit out the stock hole) The biggest thing I had to do was tig weld up some 1'' extensions on the silencer outlets to exit farther out of the belly pan (thanks SLP!) The outlets on the JAWS pipes are a massive 42mm ID! JAWS assured me that these are their "trail" pipes for such a setup... After seeing the fitment first hand they are true artists for pipe building... Ill take their word for it at 81-8300RPM which is where they told me these pipes will sing on this engine!

 

[mattymac]

also heres some classic youtube links, this is glens 1620 PSI (same cut/welded bottom end just psi cylinders built by CR racing)

https://www.youtube.com/watch?v=KxyY6ZX8KWY

and heres another CR racing creation... this is a stock 900 cylinder on the same bottom end, notice how when the sled hits the hill the pitch of the motor never changes... thats torque kids!

https://www.youtube.com/watch?v=XvXRzXTkYPQ

Heres chad's (CR racing) old personal sled... 1800, Ive personally rode with this sled and yes, its faster than it looks in this vid! Chad has told me that to this day he would put this 1800 against any mountain sled (turbo'd or whatever) in a drag race on flat snow in 500 ft for "you name the price"

https://www.youtube.com/watch?v=bLnenqoOaXY

TRIPLESWILLNEVERDIE

 

[KMMAC]

So, I have an idea for the (hot spot), maybe it would work. What if the intake side of the jet needle could be reshaped in the area that would represent the position of the needle in conjunction of half throttle? Something like a tiny groove parallel with the needle, in my thinking at that point, a little more fuel could get released in mid range and then once past mid range the needle shape returns to round taper. I figure beyond half throttle, the groove will have no negative effect on fueling because at the same time, the needle taper is changing to ad more fuel, so I would think the groove in the needle shouldn't matter.
Nice vids!!! made my hair stand on end. I know what you are saying about the erratic timing, on cat triples any way. I had a HARD running 96 zrt 800 that gave many 900s a run for their money. Although, I think that jetting leaner than recommended also played a factor. in the spring here, I could run 370 mains at alt. I had to watch the plugs but MAN would it run!!!

 

[icr]

So, I have an idea for the (hot spot), maybe it would work. What if the intake side of the jet needle could be reshaped in the area that would represent the position of the needle in conjunction of half throttle? Something like a tiny groove parallel with the needle, in my thinking at that point, a little more fuel could get released in mid range and then once past mid range the needle shape returns to round taper. I figure beyond half throttle, the groove will have no negative effect on fueling because at the same time, the needle taper is changing to ad more fuel, so I would think the groove in the needle shouldn't matter.

I had a UBR 1000 twin based on the cat 900 that had a lean spot at cruise speed. I tried a lot of different needles and eventually just chucked the needles into a drill and held some sand paper against them in the spot where it was lean. Worked great, dropped EGTs to a comfortable number for going down the trail and didn't lose performance anywhere.

 

[KMMAC]

Thanks

I had a UBR 1000 twin based on the cat 900 that had a lean spot at cruise speed. I tried a lot of different needles and eventually just chucked the needles into a drill and held some sand paper against them in the spot where it was lean. Worked great, dropped EGTs to a comfortable number for going down the trail and didn't lose performance anywhere.

Man, that gives me confidence of being able to fix a problem. Like I wrote in another thread my fab skills are not much but seeing a solution to a problem has been one of my strong points. Now if there was a way to use this to earn a living, I could do that...
So I may be able to put carbs on the M1000 I have after all. I have two ways I've come up with to do this, one, less complicated but would leave all of the efi components hooked up, buy a bracket for the tps on the throttle bodies, sinc it too the carbs and start it. The other would involve another stator, fly wheel and wiring harness which obviously would be more complicated but I don't think it would be too much.

 

[Idcatman3]

This is the timing curve in the CDI box that we sent Matty. The RPM numbers are multiplied by 1.5. So 12000 RPM on the chart is really 8000 engine RPM.

 

[Idcatman1]

There is also a stock Arctic Cat needle that is a whisker smaller than the stock 900 needle. Part number 6506-200,
9DFH2-58 instead of 9DFH2-59. I think the 58 and 59 numbers are a measurement of diameter. I was thinking thousanths of an inch but it should be metric since everything else on the carbs is metric. These needles come stock on 01 thundercats. From my experience they help a lot with the midrange hot spot. I am embarrassed that I didn't think of just spinning them in a drill and using some emery cloth to do the same trick.
Scott and I say an M1000 with carbs on it several years ago. I believe a guy who worked at Racin Station in Driggs Idaho put it together. I think he used the stock EFI electrical system. Scott might remember more.

 

[Idcatman3]

Man, that gives me confidence of being able to fix a problem. Like I wrote in another
thread my fab skills are not much but seeing a solution to a problem has been one of my strong points. Now if there was a way to use this to earn a living, I could do that...
So I may be able to put carbs on the M1000 I have after all. I have two ways I've
come up with to do this, one, less complicated but would leave all of the efi components hooked up, buy a bracket for the tps on the throttle bodies, sinc it too the carbs and start it. The other would involve another stator, fly wheel and wiring harness
which obviously would be more complicated but I don't think it would be too much.

I also think it was a guy involved with Racin Station. He tied up the fuel injectors and let them dangle under the engine. Put reed cage/carb boots on it from either an M7 carb or a 900 (reed cages are the same size) and just slapped a set of rack carbs on it, TPS and all, and ran it. He might have glossed over some of the details describing it to us, but that's all he mentioned.

 

[mattymac]

the plot thickens... I have been fighting this ignition issue and for the life of me couldnt figure out why it wasnt working right...

Two days of back and forth, measuring, removing stators, flywheels, cdi boxes, I found out that there are two different flywheels on the cat twins and the one I used to get measurements off to rekey my flywheel was the goofy one, go figure! It came out of an 03.5 1M 900 144, I kept questioning how a flywheel with only 4 degrees advance can run... I dont know but it did in the twin setup. On the correct twin flywheel it has around 43 degrees of advance. If you look at the pic, notice the keyway pointing straight up and look at the timing triggers between the two, the goofy one (left) is less advanced, or closer toward 9 o clock.

They have the same PN stamped in them FP9111

This unforeseen problem is going to cost me more downtime, and another keyway to be machined in my original tcat flywheel




This is how the trigger on the flywheel should be with the mag cyl at TDC



this is where it should not be at TDC! but for whatever reason this one off goofy cat twin flywheel ended up being the one that I ended up with to rekey my flywheel... Go figure!!!

 

[KMMAC]

Thanks

I also think it was a guy involved with Racin Station. He tied up the fuel injectors and let them dangle under the engine. Put reed cage/carb boots on it from either an M7 carb or a 900 (reed cages are the same size) and just slapped a set of rack carbs on it, TPS and all, and ran it. He might have glossed over some of the details describing it to us, but that's all he mentioned.

This 1000 ran rich on the bottom first and only time I rode it, then the gas tank cracked and when I took the tank off found bare wires at the coils. There wasn't enough wire insulation on any of the wires, so started looking further and guess what, more wires else where on the harness that were not coated well. Then I haven't been able to work on it for a while. There were several things I didn't like about the setup, it wasn't very responsive and I didn't like being pushed up against the dash. So, went looking for some parts online and now am going to do a whole make over. I thought of the carb thing and then thought just to try it why not plug a set in and see what happens. Good to know that it has been done. I will message Eric and see if he can tell me any more.
Thanks for the info. Oh I had thought that maybe I could change to a triple throttle cable to get the extra line for the tps and just hook it to the throttle body to see if she'd run. I know that Cutler's at one time had a bracket for a tps for aftermarket carbs, thought I would give him a shout to see if he had one laying around. For that matter, I could probably fab one with a metal saw and a file.
It's science, but it's not rocket science...
My wife and I are raising a great granddaughter with some minor special needs so she takes up some time. My first little one at 57, never saw myself married and now have it all. I love it. Now I will have a future riding partner! Still looking forward to the day when I can pull the cord on a slightly modded sled. What engine, not sure yet.
So once again thanks for the info..

 

[Idcatman3]

I'm juggling 3 kids of my own, not much getting done on any projects!

And when I do get to ride, they all want to go. Oldest is 6. He loves it though, I'm not about to tell him he can't go.

 

[KMMAC]

Balance

the plot thickens... I have been fighting this ignition issue and for the life of me couldnt figure out why it wasnt working right...

Two days of back and forth, measuring, removing stators, flywheels, cdi boxes, I found out that there are two different flywheels on the cat twins and the one I used to get measurements off to rekey my flywheel was the goofy one, go figure! It came out of an 03.5 1M 900 144, I kept questioning how a flywheel with only 4 degrees advance can run... I dont know but it did in the twin setup. On the correct twin flywheel it has around 43 degrees of advance. If you look at the pic, notice the keyway pointing straight up and look at the timing triggers between the two, the goofy one (left) is less advanced, or closer toward 9 o clock.

They have the same PN stamped in them FP9111

This unforeseen problem is going to cost me more downtime, and another keyway to be machined in my original tcat flywheel




This is how the trigger on the flywheel should be with the mag cyl at TDC



this is where it should not be at TDC! but for whatever reason this one off goofy cat twin flywheel ended up being the one that I ended up with to rekey my flywheel... Go figure!!!

So, slightly off topic, are fly wheels/magnetos balanced to a specific engine size?
I have had this question on my mind for a long time. Good work catching the odd ball
flywheel, man who'd a thunk, why would cat put a different flywheel on that engine?
Did the engine come out of a trail sled? If so, maybe they did it keep the engine from det. at low alt..

 

[mattymac]

So, slightly off topic, are fly wheels/magnetos balanced to a specific engine size?
I have had this question on my mind for a long time. Good work catching the odd ball
flywheel, man who'd a thunk, why would cat put a different flywheel on that engine?
Did the engine come out of a trail sled? If so, maybe they did it keep the engine from det. at low alt..

Yeah they are spin balanced like a clutch, the smaller OD makes them less prone to being out of balance.

The oddball flywheel came out of a 2003.5 900 1M... The weird thing is, with only 4 degrees advance on the trigger to the ignition sensor, technically this motor shouldnt have ran at all being that these sleds need around 40+ degrees of flywheel advance because the CDI's job is to take that high ignition advance and delay it. Most timing curves ramp timing from the upper 20 degree range at low RPM, to 10-12 degrees at around 8000 rpm. Im stumped with this specific flywheel.

 

[KMMAC]

That is interesting, would be something to see how the stator was mounted to the block on that odd ball.
So, if I understand what said about flywheel balance, then is there a difference in weight between engine size? Meaning the larger the engine the more the flywheel weighs?

 

[Idcatman3]

Nah, the flywheel is balanced by itself, not with the engine as a whole. The 570 fan uses essentially the same flywheen the 900 twin does. As did the early 2000s 440 sno pro.

Orientation of the stator doesn't matter on these either. The timing sensor is mounted outside the flywheel, not integrated into the stator like some models are.

That one's just an oddball! Matty, are you sure it's an FP9111?

 

[mattymac]

Nah, the flywheel is balanced by itself, not with the engine as a whole. The 570 fan uses essentially the same flywheen the 900 twin does. As did the early 2000s 440 sno pro.

Orientation of the stator doesn't matter on these either. The timing sensor is mounted outside the flywheel, not integrated into the stator like some models are.

That one's just an oddball! Matty, are you sure it's an FP9111?

Yep FP9111, trust me you can even see it on the side by side pic of the two flywheels... Ive looked probably a dozen times!!! Im still trying to rack my brain as to why its like this.

 

[mattymac]

Well, I figured the only way that this flywheel could have done what it did was the hub spun in the flywheel itself, I marked some lines on it, put the starter cup on, locked the flywheel in the bench vise got a 2' pry bar thinking id have to bear down on it... NOPE it spun with very little effort. Im not sure when it spun, im figuring when I pulled it off the crank with the flywheel puller.




The good news is, I have figured out this un-foreseeable problem and the tcat flywheel is getting a new keyway punched in it at my machine shop to tackle this issue and I should be up and running soon... FINALLY!

Gotta love these totally custom build projects you never know what your gonna encounter along the way, but this is how we all learn!

 

[Zrt1200]

Yep FP9111, trust me you can even see it on the side by side pic of the two flywheels... Ive looked probably a dozen times!!! Im still trying to rack my brain as to why its like this.

That Sucks you have this problem being its winter now. Glad you are figuring it out. Can you post a pic after you get your flywheel re-machined to where the trigger is in relationship to the flywheel at TDC.

On our Prostock drag race sled we have 32* of initial timing and 15* of finish timing. Im not sure a pump gas engine can use as much timing as a race engine or not. It will depend mostly on the quality of fuel you can get.

Only if we could get a MSD to charge its own battery

Here is a couple pics of a 4 cylinder ZR900 crankshaft?? It has ZR900 cylinder heads on it anyways. This engine produce 430HP. It is in getting repaired (New PTO End) because of a blown belt that got wrapped around the clutch and those ties they put on between the clutchs on the Mod sleds now days.

 

[Zrt1200]

This is the timing curve in the CDI box that we sent Matty. The RPM numbers are multiplied by 1.5. So 12000 RPM on the chart is really 8000 engine RPM.

You can change the timing at home???

 

[Idcatman3]

You can change the timing at home???

I can't, but I know a guy... Might not be able to much longer, the software is way out of date.