I'm skeptical that's two 900 twin cranks. The water pump drive is wrong. Looks like a ZRT or T-cat with an extra cylinder.
Old school, big power
- Thread starter mattymac
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I'm skeptical that's two 900 twin cranks. The water pump drive is wrong. Looks like a ZRT or T-cat with an extra cylinder.
Z
Zrt1200
Member
Agreed, I did not see the whole engine just the crank & heads which were ZR900 heads. There is no mistaking round heads for 6 sided heads on a ZRT/T-cat. I am assuming its a one of specialty build.
Z
Zrt1200
Member
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!!!
Take a look at Hoopers web site. He says there are some flywheels that are not keyed right. Look under Predator 1035 in the link.
http://www.hooperraceengines.com/resources
Here is a copy and paste of it.
Predator 1035 - We have found that some of the 800 + 900 ignitions have less timing
than others and may require a larger offset key for best performance. If your 1035 will not
pull 76 gram arms to at least 7900 R.P.M. this may be the problem.
*To check (have your dealer do this) - Using a dial indicator, put a mark on the flywheel
when piston is .050 before T.D.C., then check with timing light at full throttle, this can be
done on a jack-stand with brief full throttle bursts. If timing is less than .045 at full throttle,
then a larger offset key should be installed. (each .007 of key offset = approx .010 more
timing advance, measured in piston travel)
**Example: If your engine has .030 timing (instead of .050) when checked and you have
a .020 offset key installed, then you need to install a .035key, which should give you
approx. .050 timing advance, measured in piston travel.
*Important - Whenever you change the flywheel key you MUST use your dial indicator
again and remark the flywheel.
Z
Zrt1200
Member
Ya I here you and Now Cat is getting sold so who knows if you will be able to in the future. You might want to get a few spares reprogrammed now just in case??
Z
Zrt1200
Member
I just got off the phone with northern cranks and have another call to make later to a guy who asphalt races these but.. John at Northern crank told me you can balance your crank two ways. One is the typical add weight or Two you can pork chop the crank and remove weight and rotating mass.
He also told me these cranks live a lot longer & better as a 3 cylinder than they ever did as a twin cylinder!!
He also told me these cranks live a lot longer & better as a 3 cylinder than they ever did as a twin cylinder!!
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Z
Zrt1200
Member
I got a hold of the guy I wanted to get a hold of who has 3 of these engines set up for asphalt racing. He has 3 different style of crankshafts that John Roland had built him.
One, is a stock crank that was balanced and had extra weight add'ed to it. he said it just does not run like the other two cranks so dont bother with it.
Two, is a stock crank that is balanced. He says this crank runs very good.
Three is the pork chopped crank. He said this crank makes a few more HP on the dyno and it spins up faster but there is Zero ET difference in the real world and he said he would not spend the extra money again to have it done or the extra weighted one.
He says these cranks hold up great and Do not ever push them past 8500Rpm's. At 8500 Rpms its turning the same Piston speed as a T-cat running at 10,000 Rpms. At 8300 it is equal to the T-cat spinning 9700Rpm's. Granted unless its a race sled you wont be at that Rpm all the time though.
He and John also told me to replace the PTO end bearing every year as these mod engine will eat the PTO bearing at over 300HP. They both said these cranks hold up great. John told me they we live longer as a triple than as a twin.
His one engine is a 4 cylinder ZR900 based!! He has hooper trail 1100 on one. Hooper race 1100 on another one and a cultler 1147 on the 4 cylinder. So his smallest engine is a 1650cc that makes 340HP with there MSD and Jaws race pipes on 112 octane fuel.
I asked if he felt there would be any over heating problems with the casted case with only one water pump and he said No. Cutler use to run a 1147 with his own casted case with no problems on the trail.
He told me Cutler had two versions of this case. One for the standard cylinder and one for the big bore cylinders. he said the only difference is the bore diameter where the cylinder slides into the case and they just bore it out bigger to except the big 1100 cylinders. he said Hoopers cylinders are even bigger at the bottom to fit into the case than the cutlers is.
He told me the reason why they went to a MSD was more from the problems he was having with the carb end VS the EFI end on the mag side with the flywheel. He said he thinks its more harmonics than anything causing the problem. Sounds like you should get the flywheel balanced IMO. Smitty's in Michigan does a good job at a reasonable price. He balances clutchs and all sorts of things there.
http://www.smittysengtrans.com/
He next told me of a adjustable pick up sensor mount for the cast case. He said you can you can move the timing approximately 25 degree's. He told me you should be able to get one from cutlers as he made up 10 of them last year for them. If any one has one please post a pic so we all can see it.
I asked about carb size for his 1100 engines and he said the best carb size was 44 to 46mm. He said smaller really chokes the engine down and over he see's no gain. He races at 7500ft of elevation and said being I am a flatlander at 800 to 1100ft I would probable see a increase because of air density. he said he has had zero issue running 40 to 1 with amsoil.
I asked about his jaws race pipes and he said they are a split between the D series and the D&D race pipes. So from what I have learned it sounds like the best pipe is the Jaws D series spinning at 8300 or slower.
He told me the 1100 casting has a ton more transfer port opening to the point you need to modify the case to match. He said its like a 1/4" or bigger the case needs to be opened up. Thats the summary of what we talked about. I hope this helps some of you guys out.
One, is a stock crank that was balanced and had extra weight add'ed to it. he said it just does not run like the other two cranks so dont bother with it.
Two, is a stock crank that is balanced. He says this crank runs very good.
Three is the pork chopped crank. He said this crank makes a few more HP on the dyno and it spins up faster but there is Zero ET difference in the real world and he said he would not spend the extra money again to have it done or the extra weighted one.
He says these cranks hold up great and Do not ever push them past 8500Rpm's. At 8500 Rpms its turning the same Piston speed as a T-cat running at 10,000 Rpms. At 8300 it is equal to the T-cat spinning 9700Rpm's. Granted unless its a race sled you wont be at that Rpm all the time though.
He and John also told me to replace the PTO end bearing every year as these mod engine will eat the PTO bearing at over 300HP. They both said these cranks hold up great. John told me they we live longer as a triple than as a twin.
His one engine is a 4 cylinder ZR900 based!! He has hooper trail 1100 on one. Hooper race 1100 on another one and a cultler 1147 on the 4 cylinder. So his smallest engine is a 1650cc that makes 340HP with there MSD and Jaws race pipes on 112 octane fuel.
I asked if he felt there would be any over heating problems with the casted case with only one water pump and he said No. Cutler use to run a 1147 with his own casted case with no problems on the trail.
He told me Cutler had two versions of this case. One for the standard cylinder and one for the big bore cylinders. he said the only difference is the bore diameter where the cylinder slides into the case and they just bore it out bigger to except the big 1100 cylinders. he said Hoopers cylinders are even bigger at the bottom to fit into the case than the cutlers is.
He told me the reason why they went to a MSD was more from the problems he was having with the carb end VS the EFI end on the mag side with the flywheel. He said he thinks its more harmonics than anything causing the problem. Sounds like you should get the flywheel balanced IMO. Smitty's in Michigan does a good job at a reasonable price. He balances clutchs and all sorts of things there.
http://www.smittysengtrans.com/
He next told me of a adjustable pick up sensor mount for the cast case. He said you can you can move the timing approximately 25 degree's. He told me you should be able to get one from cutlers as he made up 10 of them last year for them. If any one has one please post a pic so we all can see it.
I asked about carb size for his 1100 engines and he said the best carb size was 44 to 46mm. He said smaller really chokes the engine down and over he see's no gain. He races at 7500ft of elevation and said being I am a flatlander at 800 to 1100ft I would probable see a increase because of air density. he said he has had zero issue running 40 to 1 with amsoil.
I asked about his jaws race pipes and he said they are a split between the D series and the D&D race pipes. So from what I have learned it sounds like the best pipe is the Jaws D series spinning at 8300 or slower.
He told me the 1100 casting has a ton more transfer port opening to the point you need to modify the case to match. He said its like a 1/4" or bigger the case needs to be opened up. Thats the summary of what we talked about. I hope this helps some of you guys out.
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Z
Zrt1200
Member
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!
If these flywheels are just pressed in couldn't you just press it out and turn it to the correct timing and press back together?? Then weld it so it can not move and have it re balanced.
Z
Zrt1200
Member
I was just thinking about your Flywheel spinning so I went out to the garage and took a few pics of the 93-97 T-cat /Zrt800 NCI Flywheel. There is no way this flywheel could ever spin. Take notice of the Key position on the NCI flywheel in regards to the timing sensor and notice it only has 4 magnets. Its also riveted together so it would never spin.
Also this is the flywheel you must use if setting up a MSD digital 7 to go on a T-cat or in this case a ZR1400 as they drill the rivets out and use this hub to bolt the MSD flywheel to. I have drilled one of these out for a MSD. The rivets are like a flat head screw so the opening in the flywheel is counter sunk for the rivet on the starter cup side.
Also this is the flywheel you must use if setting up a MSD digital 7 to go on a T-cat or in this case a ZR1400 as they drill the rivets out and use this hub to bolt the MSD flywheel to. I have drilled one of these out for a MSD. The rivets are like a flat head screw so the opening in the flywheel is counter sunk for the rivet on the starter cup side.
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The polaris watercraft engines Ive built, I always used the 680 ultra ignitions, along with a PAR billet hub that you had to re-rivet into the flywheel.
It had the correct keyway slot and the correct taper. In the earlier years (late 90's) when we were builing the watercraft triples we would retaper the hub on an edm which sometimes took a few times to get the depth right but we get em to work perfectly.
As far as the cat hub that twisted, to my knowlage they are fusion welded, im more surprised that it didnt fall out!
https://www.youtube.com/watch?v=-aEuAK8bsQg
It had the correct keyway slot and the correct taper. In the earlier years (late 90's) when we were builing the watercraft triples we would retaper the hub on an edm which sometimes took a few times to get the depth right but we get em to work perfectly.
As far as the cat hub that twisted, to my knowlage they are fusion welded, im more surprised that it didnt fall out!
https://www.youtube.com/watch?v=-aEuAK8bsQg
Z
Zrt1200
Member
Well my curiosity got me out to the garage to get some measurement to compare the two flywheels. I hope you guys can read my writing as that is not my strong suite at all and my drafting skills are not much better. lol.
On the Zrt600 I did not measure to the outside where the recoil cup bolts on. I just measured the width of the actual Flywheel.
On the T-Cat flywheel I measured to the outside to where the recoil cup bolts on. I did not realize I did that until now.
I had sent Idcatman3 a PM to see if he had any ZR900 EFI flywheels and asked if he could take some measurements so we can compare them.
On the Zrt600 I did not measure to the outside where the recoil cup bolts on. I just measured the width of the actual Flywheel.
On the T-Cat flywheel I measured to the outside to where the recoil cup bolts on. I did not realize I did that until now.
I had sent Idcatman3 a PM to see if he had any ZR900 EFI flywheels and asked if he could take some measurements so we can compare them.
Good Question I had
That was a good question I PM'D to you yesterday... Except for space,
I don't see any issue with running something like this to add crank
bearing life to the pto side...
That was a good question I PM'D to you yesterday... Except for space,
I don't see any issue with running something like this to add crank
bearing life to the pto side...
Z
Zrt1200
Member
I have checked a lot into crankshafts and ignitions on this build. On the crankshaft's I have called both Northern cranks and Crankworks. Both places static balance cranks. Crankworks offers a Billet 1 piece end. So just by that if I was building a crank I would send it to Crankworks. JMO.
On the Ignition Its no brainier IMO if buying a cast 3 cyl case. Bolt on a 93-97 T-cat/Zrt800 ignition and buy the adjustable trigger housing from Cutler from what I understand is $300.
The trick with the Flywheel after calling 8 different people both in the USA and Canada is to make a extra long key that fits the flywheel tight so there is Zero slop in between the key and the flywheel and add a extra 10lbs when torquing. Personally I would use one drop of green loctite gap filler on the taper. Ya it would be a bitch to get back off but it would make sure its not coming loose.
I called D&D and they have 1010 & 1147 non plated cylinders that are already ported for $400ea. They need to use there insert heads as the bolt hole pattern is spaced further out and those are $85 for the hats and $85 for the inserts. The piston kit for those cylinders are $200ea. They also have the engine mounts to bolt the cast case into the chassis.
I also found out the D&D 1010 uses F7 pipes on it. I found that in D&D jetting chart.
To make the power I would want out of this engine I would have a lot of cash invested. That is not saying i would have to put it all up front to get the engine going though as a 975 Big bore is still going to make some Good Power with out spending extra on D&D stuff.
From what I have been told on this 975 BB triple you can expect around 275HP out of the build with pretty heavy porting. 275HP is a lot more than most boosted turbos on the snow and there is No Lag.
On the Ignition Its no brainier IMO if buying a cast 3 cyl case. Bolt on a 93-97 T-cat/Zrt800 ignition and buy the adjustable trigger housing from Cutler from what I understand is $300.
The trick with the Flywheel after calling 8 different people both in the USA and Canada is to make a extra long key that fits the flywheel tight so there is Zero slop in between the key and the flywheel and add a extra 10lbs when torquing. Personally I would use one drop of green loctite gap filler on the taper. Ya it would be a bitch to get back off but it would make sure its not coming loose.
I called D&D and they have 1010 & 1147 non plated cylinders that are already ported for $400ea. They need to use there insert heads as the bolt hole pattern is spaced further out and those are $85 for the hats and $85 for the inserts. The piston kit for those cylinders are $200ea. They also have the engine mounts to bolt the cast case into the chassis.
I also found out the D&D 1010 uses F7 pipes on it. I found that in D&D jetting chart.
To make the power I would want out of this engine I would have a lot of cash invested. That is not saying i would have to put it all up front to get the engine going though as a 975 Big bore is still going to make some Good Power with out spending extra on D&D stuff.
From what I have been told on this 975 BB triple you can expect around 275HP out of the build with pretty heavy porting. 275HP is a lot more than most boosted turbos on the snow and there is No Lag.
Good stuff,,, so are the F7 pipes trail or race? Would it be possible to use the 900 twin hub with the triple
magneto? Seems that if the hub will fit inside then the rivets could be drilled and just use grade 8 bolts to hold it together...
magneto? Seems that if the hub will fit inside then the rivets could be drilled and just use grade 8 bolts to hold it together...
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Alright... I have a confession the reason I haven't posted any updates is I have an issue with my motor... I have tried everything, most things two or three times with the same result! This issue has incorrect timing all over it in my opinion, but I've had my initial flywheel timing indexed at anywhere from 15 degrees btdc all the way to 45 degrees btdc and it runs literally the exact same! I have even gone so far as to thinking i had an air leak causing a lean cylinder to not fire this running on 2 cylinders so after pulling the motor completely back apart re sealing the case halves and installing new crank seals pressure testing the motor to 8+ psi it still runs the same, different coils another tcat CDI box, different stators, it still runs the same... I am working on another flywheel I don't know if the edm machine messed up this flywheel but it's the only thing I haven't changed! The weird thing is I couldn't get spark from the twin CDI/stator setup but the tcat CDI/stator gets really strong spark? I don't know if the flywheel magnets got messed up somehow in the edm process of retapering and rekeying it, which I find hard to believe since I have great spark and lighting coil power but I've tried every thing else! If you look about 3/4 through the video it shoots flame back through the carb... This is the first time I've noticed it back through the intake side mostly it's been out the pipe! TIMING IS OFF I know right!?!? But I've changed over 30 degrees and it acts the same exact way!!! I can't think of what else it can be
https://youtu.be/YmLDHsIVpuQ
https://youtu.be/YmLDHsIVpuQ
Z
Zrt1200
Member
I will look at you video and reply tomorrow more. But by chance did you check the crank indexing??? With a 3 cylinder firing every 120 degree's it's easy to check. Bring one cylinder up to TDC and the other 2 pistons should be at the same height.
You can measure this through the plug holes pretty easy. And yes I have had fresh crankshafts not indexed properly before. I always check them before putting case sealant on after having my first bad index 15 years ago.
You can measure this through the plug holes pretty easy. And yes I have had fresh crankshafts not indexed properly before. I always check them before putting case sealant on after having my first bad index 15 years ago.
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