viper er rpm drop from 8500 to 8000

SHARKATTAK

SHARKATTAK

New member
Joined
Jan 14, 2006
Messages
44
Location
MASS.
it seems i am loosing 500 rpms, when i hammer the flipper it take right off holds 8500 but then it is dropping back to 8000, here is my set-up dalton blue/black w/ 8dn-2o, 4.5 in each hole in primary, secondary silver at 90, carbs cleaned no bog, bender pipes carbs have 167.5 main jets, 52.5 pilot, 2 turns out, power valves are cleaned and set right, track is hacksaw 1" x121 144 1.075 gold diggers, expert -x suspension, stock gearing,condition on ice hard snow about 2 in. i was going to try a 80 wrap, then 70, then 60 today, any help would be great thanks
 
i think (the way i'm seeing it, but i'm no clutch expert by any means) the more you loosen the wrap the worse it will probably be, the less tension you put on the spring the secondary will shift out further faster lowering your rpms even more
 
Try this

I'm unable to really tell you exactly what to do because I don't know exactly when your RPM's are dropping....ie at 20 mph or at 70 mph. But it sounds like the problem is that you are overshifting. It's true above that less wrap on the secondary spring is going to make the problem worse. Since you are already using a silver secondary spring I'd have to say it's likely that your helix is a little to steep combined with the fact that 4.5 grams in both holes might be a little much weight for a stock viper motor. If you tell me what helix you are using I'll be able to give you info on which way to go. I'd guess that you wouldn't want to be any steeper than say a 51/45. Let me know & I'll check back.

Madmatt

PS: For the record, my 780 viper wouldn't pull that much weight in the primary but I was also spinning 9100 RPM's so that makes a pretty big difference.
 
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are you still running the stock 47 straight helix? just like madmatt said, seems to me that you're overshifting. let us know what helix you got now, and we can point you in the right direction.
 
Primary

What make is the helix? If it's a Dalton or a Hauck then your OK if it's an Advant Edge or somthing like that then you're too steep.

I think you need to take some weight out of the primary. Go with like 3.3 or 3.6 in the tip. Got any 15 or 15.6 rollers? I like the way 8dn 20's shift a lot better with larger rollers.....if not then just leave the 14.5's. After you make the change above if it happens to over rev a little then go to a green spring at like 70. You are close.

Madematt
 
thanks Matt, when i get back home i'll pick up some 3.6 rivets,yes, it's a dalton, everything is running awesome except that
 
IMO, the 52/46 helix is the problem. i would try like a 52/42 or 52/40 helix. i have a maxx perf 52/40 helix if interested. i strongly feel that the finish angle is too steep. tip weight could be lessed to a 3.6g like madmatt suggested, or even a 3.1g. w/a 52/42 or 52/40 helix, i would suggest the green spring at 70 for starters.

how do the clutch temps feel now on both the pri and sec? are there any darker lines/marks on either clutch, to indicate belt slippage?
 
Try it first

Mopar, just last year you were on here asking all kinds of questions about clutching and now you answer almost every post about clutching like you are some kind of authority. I am a novice clutch tuner at best and I've been at it a lot longer than a year or two. A 46 degree finish on a dalton is NOT too steep for a viper with 8DN-20's. The weight isn't THAT aggressive. Could a shallower finish work better???? Maybe. But let's not have him go out and chase $100 helix's when he can change $1 rivets. The guy has too much weight in the primary. Besides, where did you learn to tune RPM with helix changes? If you've got a reasonably correct helix (which he does) then going to the secondary to tune RPM is the #1 thing NOT to do.

Madmatt
 
HELIX MIGHT BE WRONG HERE BUT I WOULD GET WEIGHT OUT OF THE PRIMARY. GUYS VERY COMMON POSTS ON HERE ABOUT RPM IS LOW AFTER GOOD TAKE OFF AND MID. EITHER TWO THINGS CAUSE THIS, TO MUCH WEIGHT IN PRIMARY OR WRONG HELIX. NOW SPRINGS IN CLUTCHES COULD ADD TO PROBLEM, BUT NOT IF YOUR STRONG LOW AND MID. AGAIN, YOU HAVE TO HAVE EXTRA CLUTCH PARTS SO YOU CAN TRY DEFFERENT THINGS. ALL MOTORS ARE DEFFERENT. 3:16 (yammie tony)
 
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GUYS QUICK STORIE. I SCREWED AND SCREWED WITH A RED HEAD TRIPLE SX 700 LAST YEAR ON TAR. FULL BENDER PORTED , TRIPLE PIPED, YOU GUYS KNOW THE SLED. COULD NOT GET AND KEEP RPM UP, CHASED THAT GOD DAM SECONDARY ALL OVER THE PLACE, HELIX, WRAP, SPRINGS. FINALLY GOT MY HEAD OUT OF MY ***, WENT AFTER PRIMARY. 10.18 @ 125 @ 8900/9000. END OF STORIE. HAVE TO TUNE YOUR PRIMARY. 3:16 (yammie tony)
 
Another reply

Tony, why do you say the helix is WAYY wrong here. What have you run in your viper with these weights.....oh, wait....I'm sorry....do you have a viper? LOL!

OK, guys, lets not get in a big argument here.....this is good discussion we are having. I've always wondered, is there a rule of thumb on where to start with a helix? If this guy wants to try another helix I've got a Dalton 52/42 I'll mail him. If it works better than less weight in the primary then he can buy it....if not then he can just send it back. You both know there is more than one way to skin a cat and in this case I don't think the cost of a different helix is worth it. He's probably smarter than Josh, Tony and me in that he doesn't have a tool box full of helix's he'll probably never use sitting in his garage.

Madmatt
 
YAMIGOD not fair!

I see you did a little editing after you read my post!! LOL! Good story about the SX. If he got the helix to try then fine....but I say he's still got way too much weight in the primary. The change I gave him still wont be enough. I predict he's gonna end up going to a green spring in the secondary and less weight in BOTH holes.

Madmatt
 
Madmatt said:
Mopar, just last year you were on here asking all kinds of questions about clutching and now you answer almost every post about clutching like you are some kind of authority. I am a novice clutch tuner at best and I've been at it a lot longer than a year or two. A 46 degree finish on a dalton is NOT too steep for a viper with 8DN-20's. The weight isn't THAT aggressive. Could a shallower finish work better???? Maybe. But let's not have him go out and chase $100 helix's when he can change $1 rivets. The guy has too much weight in the primary. Besides, where did you learn to tune RPM with helix changes? If you've got a reasonably correct helix (which he does) then going to the secondary to tune RPM is the #1 thing NOT to do.

Madmatt
Click to expand...

um, sorry madmatt, but it wasn't just last year that i had some clutching questions. for the last 3 yrs, i've been doing nothing but testing different clutch setups on multiple sleds. everyone @ work gives me shit, cause i always have my clutches apart to try something different. i've even tried up to 15 different combos on 1 sled alone. you know how many different weights i have and tried? you know how many different springs i have and tried? you know how many different helixs i have and tried? you know how many different roller secondaries i own and have tried? no you don't. i've learned alot since i started this clutching thing. i've been doing just as much of this clutching gig as you have. also, after a while of gathering notes and seeing what affect takes places after "this" or "that" change, one can start to predict outcomes pretty good. hence the reason some guys can shoot out a setup/ballpark setup, and it be within 100 rpm or so, from what's needed. i never ever said that i had any kind of "authority" here. not sure why you feel this way and why i seem to not be able to get any kind of respect on here. this is a public forum, where we are all able to share our thoughts and such. you post what you feel is going to help this guy out and i will do the same. this guy was just looking for some help, and i stated what i feel is the correction to the problem. don't know why you are knocking on me for helping a fellow TY member out?? yes, aaen's clutching book says to tune rpms w/primary, but i'm sure that is w/the correct helix in clutch. also, if one has too steep of a helix, it will lug the engine and overshift. if one has that problem, taking 1 gram or so out of primary isn't the answer. a helix change is in order....sometimes the secondary needs work to keep rpms where they need to be. if he can pull near the correct rpm needed (he's pulling 8500 when he should be pulling 8800), for up to 65mph, and then rpms start to fall off, in my testing/tuning experience, it has shown me that the finish was too steep, and the secondary is opening up too fast. madmatt, if you always have to tune the primary for the correct rpm's, then why is there more than 1 helix angle available? if your suppose to be able to just change rivets to correct the rpm problem, w/whatever weights are in the primary, then there wouldn't be all these different angles available aftermarket and from OEM. there has to be a balance between the secondary and primary. also, that's great that you want to maybe save the guy some $, if the helix don't work, but sometimes a person may need to buy multiple parts to try/test out, like tony said. hence the reason i have tons of dollars in clutching stuff. not saying this guy has to spend thousands or even hundreds. i think its a great jesture on your part, to offer to mail your helix to him, for trial. lets have him try that helix out and have him report back??

my guess is if he just takes a little weight out of the primary, it will run 100-200 rpm higher up to 65mph or so, and then start to drop down near 8000 or so again.
 
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im no were near the clutch experts(not even close) you guys are, but i think you all make good points and are helpful at giving different avenues
 
MATT, I 100 % AGREE WITH YOU. THATS WHY A CHANGED MY POST. ALL I DID WAS THINK OF THE SCREWING AROUND I DID ON THE ASPHALT UNTIL I WENT AFTER PRIMARY. 3:16 (yammie tony)
 
mopar1rules said:
um, sorry madmatt, but it wasn't just last year that i had some clutching questions. for the last 3 yrs, i've been doing nothing but testing different clutch setups on multiple sleds. everyone @ work gives me shit, cause i always have my clutches apart to try something different. i've even tried up to 15 different combos on 1 sled alone. you know how many different weights i have and tried? you know how many different springs i have and tried? you know how many different helixs i have and tried? you know how many different roller secondaries i own and have tried? no you don't. i've learned alot since i started this clutching thing. i've been doing just as much of this clutching gig as you have. also, after a while of gathering notes and seeing what affect takes places after "this" or "that" change, one can start to predict outcomes pretty good. hence the reason some guys can shoot out a setup/ballpark setup, and it be within 100 rpm or so, from what's needed. i never ever said that i had any kind of "authority" here. not sure why you feel this way and why i seem to not be able to get any kind of respect on here. this is a public forum, where we are all able to share our thoughts and such. you post what you feel is going to help this guy out and i will do the same. this guy was just looking for some help, and i stated what i feel is the correction to the problem. don't know why you are knocking on me for helping a fellow TY member out?? yes, aaen's clutching book says to tune rpms w/primary, but i'm sure that is w/the correct helix in clutch. also, if one has too steep of a helix, it will lug the engine and overshift. if one has that problem, taking 1 gram or so out of primary isn't the answer. a helix change is in order....sometimes the secondary needs work to keep rpms where they need to be. if he can pull near the correct rpm needed (he's pulling 8500 when he should be pulling 8800), for up to 65mph, and then rpms start to fall off, in my testing/tuning experience, it has shown me that the finish was too steep, and the secondary is opening up too fast. madmatt, if you always have to tune the primary for the correct rpm's, then why is there more than 1 helix angle available? if your suppose to be able to just change rivets to correct the rpm problem, w/whatever weights are in the primary, then there wouldn't be all these different angles available aftermarket and from OEM. there has to be a balance between the secondary and primary. also, that's great that you want to maybe save the guy some $, if the helix don't work, but sometimes a person may need to buy multiple parts to try/test out, like tony said. hence the reason i have tons of dollars in clutching stuff. not saying this guy has to spend thousands or even hundreds. i think its a great jesture on your part, to offer to mail your helix to him, for trial. lets have him try that helix out and have him report back??

my guess is if he just takes a little weight out of the primary, it will run 100-200 rpm higher up to 65mph or so, and then start to drop down near 8000 or so again.
Click to expand...
LET ME TELL YA YOU HAVE MY RESPECT. YOU DON,T HAVE TO INPRESS ME. YOUR POSTS HAVE HELPED ME A ZILLION TIMES AND A TELL YA THIS KID TEST AND TEST, AND TESTS. AND I SAY THE SAME FOR MATT. BOTH YOU GUYS HAVE HELPED ME ESPECIALLY WITH PARTS. BUT NOW I,LL GIVE YA THE OLD MAN CRAP. AT 52 AND BEEN AROUND YAMAHA SINCE 1975, EVERYBODY HAS A OPINION OF WHAT WORKS. HAVE TO TEST. 3:16 (yammie tony)
 
wow this is kind of turning into a pissing match lol. Its getting hard to read.

Im by know means a clutching expert but I can tell you from all my trail and errors weekly, mostluy errors. That I would first start by removing some weight out of the tip its cheaper. If you still find that helix is too steep then change it. I think that helix will be to steep in the long run, you are missing 800-900rpm(bender pipes)you would need to remove about 3 grams per arm. or take the 4.5gram rivet out of the tip and leave it empty and go to a green secondary spring.

Hope this helps
 
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