TM1 crank heavier?

[dktraw]

so we just finished both mine and my friends TM1s. have a couple rides in on them and have noticed that both are max rpms have dropped 200 to 300 rpm. neither of us changed anything else while in there. so only thing i can think of is that the new crank, or clutch is just a little bit heavier. just something to consider for anyone thinking about doing the TM1, lighter weights may be needed in your primary.
would this make sense or are we missing something else.

 

[Z-Man]

so we just finished both mine and my friends TM1s. have a couple rides in on them and have noticed that both are max rpms have dropped 200 to 300 rpm. neither of us changed anything else while in there. so only thing i can think of is that the new crank, or clutch is just a little bit heavier. just something to consider for anyone thinking about doing the TM1, lighter weights may be needed in your primary.
would this make sense or are we missing something else.

TM1 crank has a larger end on it. It makes sense it would be heavier but the weight being near the center shouldn't affect it much. Maybe the new clutch that comes with it has slightly different weight too?

Did you install new pistons? Your engine may need some miles put on it to get the rings seated in so it makes the same power.

 

[05900]

Break in is difficult tuning...running oil in gas?? etc will throw off rpm's as well.

 

[dktraw]

top end was not changed at all same rings, same pistons. and the new clutch i put my same weights in as well. i am running a 100:1 in every tank of gas now, i wasnt doing that before. is that enough oil to bring the Rs down. Thanks guys

 

[Z-Man]

top end was not changed at all same rings, same pistons. and the new clutch i put my same weights in as well. i am running a 100:1 in every tank of gas now, i wasnt doing that before. is that enough oil to bring the Rs down. Thanks guys

Same clutch weights and spring too? How old is your spring? I wouldn't think you would see any difference in your RPM's due to weight on the crank. Heavier crank might not be as snappy though. Does your new primary have the ring gear on it or not?

 

[dktraw]

Same clutch weights and spring too? How old is your spring? I wouldn't think you would see any difference in your RPM's due to weight on the crank. Heavier crank might not be as snappy though. Does your new primary have the ring gear on it or not?

bought a new spring from dan when doing the bottom end. spring was the same as the old one, and the weights are the same. my old primary did not have the ring gear on it, nor does the new one. motor feels just as snappy as before.

 

[Z-Man]

Here is another thought for you. If your old clutch was worn and was not shifting properly your engine may have been revving higher. The new clutch may be shifting more smoothly which may have caused the change if no other changes have been made to your clutching.

 

[dktraw]

Here is another thought for you. If your old clutch was worn and was not shifting properly your engine may have been revving higher. The new clutch may be shifting more smoothly which may have caused the change if no other changes have been made to your clutching.

ya thats true. not complaning to much, worked out good for me. i was over revving before at 8000, now im right were i should be, down to 7750,7800.
Thanks for the input

 

[mountainhorse]

Isn't the TM-1 a stock 32mm crank with a tripple bearing and snap ring kit on it?? (not a billet end)

If so, I belive the weight of the crank is the same.

 

[mountainhorse]

Isn't the TM-1 a stock 32mm crank with a tripple bearing and snap ring kit on it?? (not a billet end)

If so, I belive the weight of the crank is the same.

 

[dktraw]

Isn't the TM-1 a stock 32mm crank with a tripple bearing and snap ring kit on it?? (not a billet end)

If so, I belive the weight of the crank is the same.

yes the TM1 is the updated 32mm crank from polaris, that dan works his magic on. its jsut that we had both mine and my buddies sleds drop the same amount of rpm after the TM1. has any body else with with a TM1 experienced this same thing.

 

[Z-Man]

Isn't the TM-1 a stock 32mm crank with a tripple bearing and snap ring kit on it?? (not a billet end)

If so, I belive the weight of the crank is the same.

weren't they 30mm from the factory? The updated is 32mm would require more metal, but since it is near the center of the rotating axis it shouldn't affect anything.

 

[POLZIN]

1mm per side is only .03937" anyway! not much difference in weight especially at that diameter. that could very easily be a slight difference in the weight of the clutch. since it is different than original. even idle speed is allowed 200 rpm tolerance band per the manual .I would put a different spring with a lower finish rate . like SLP blue /red vs the blue pink/ which is what I run due to high elevation.

 

[guidoxpress]

ya thats true. not complaning to much, worked out good for me. i was over revving before at 8000, now im right were i should be, down to 7750,7800.
Thanks for the input

ok i dont get this..

you got a dope crank setup by the best builder alive...

you said you were over revving 8000 rpms...

you drop to 7800 rpms..where you should be in the first place, and your complaining about losing rpm?

 

[faulk222]

^^^^ what he said X2

 

[dktraw]

ok i dont get this..

you got a dope crank setup by the best builder alive...

you said you were over revving 8000 rpms...

you drop to 7800 rpms..where you should be in the first place, and your complaining about losing rpm?

not complaining on my part, really like were im at now, but it didnt work out for my buddy so well. he is down to 7500. so now he has to buy new weights.
i mainly posted this for future TM1 owners, so that they would know that they may have to do a little extra to get there rpms back, thats all.

 

[ck3700]

not complaining on my part, really like were im at now, but it didnt work out for my buddy so well. he is down to 7500. so now he has to buy new weights.
i mainly posted this for future TM1 owners, so that they would know that they may have to do a little extra to get there rpms back, thats all.

Not sure how "stock" your engine is other than the tmi crank, But I was under the impression that these motors made peak power at 7200 to 7300, and fell off quite rapidly thereafter..?? Dyonport told me with their pipe set up to tune for 7400 to 7500 rpm, no more..?? Am I missing something?

 

[guidoxpress]

Not sure how "stock" your engine is other than the tmi crank, But I was under the impression that these motors made peak power at 7200 to 7300, and fell off quite rapidly thereafter..?? Dyonport told me with their pipe set up to tune for 7400 to 7500 rpm, no more..?? Am I missing something?

lol, this is a battle...SLP pipe/y-pipe/can and ECU reflash states 7600-7800, and thats what i have been running on an 05 RMK 900, 06 RMK 900 and 06 RMK 700...for years and prefer it..

however, Dynoport pipe/can/y-pipe with NO reflash states 7400...but i am a FIRM believer that the 7400rpm load range is the killer for the stock cranks...and spinning them faster then 7400 is better for the crank IMO.

my buddy Z-Man is a firm believer in Dynoport, but i am not..i am an SLP supporter...

its your decision on who you prefer...like Avgas vs Race fuel...which oil to use...but hopefully you'll find out that I am right

 

[dktraw]

i have the full slp setup on my 900, and my buddys is same minus his cpi can. so we are both shooting for the 7600-7800 rpm range.

 

[ck3700]

lol, this is a battle...SLP pipe/y-pipe/can and ECU reflash states 7600-7800, and thats what i have been running on an 05 RMK 900, 06 RMK 900 and 06 RMK 700...for years and prefer it..

however, Dynoport pipe/can/y-pipe with NO reflash states 7400...but i am a FIRM believer that the 7400rpm load range is the killer for the stock cranks...and spinning them faster then 7400 is better for the crank IMO.

my buddy Z-Man is a firm believer in Dynoport, but i am not..i am an SLP supporter...

its your decision on who you prefer...like Avgas vs Race fuel...which oil to use...but hopefully you'll find out that I am right

Gotcha!! I would think that more rpm, with the same gearing would = more speed at full shiftout, if you could pull it..
First time I EVER heard of 7400 being a critical rpm for crankshaft failure.. I have heard it stated to stay away from 7700 plus, for that same reason. If you tune for higher than 7400, you would hit the rpm range on the way up, and down , even if it was not for a sustained period..
I have seen the dynoport set up handily beat the slp in person though, but every tuner, set up, and set of conditions is different. A couple sled lengths wouldn't be worth it at the cost of a crankshaft,if that were true, I guess.. Heard that the stock exhaust works well with SLP's reflash, but don't have firsthand info.

To the original poster, Did you ever ask Dan this question about RPM's dropping, or if this is normal? I bet he could shed some light here, and about critical RPM's also. He has forgotten more on these sled motors than we will ever know..