Wizard
Member
I'm a mech. engineer (hands on is how I learn, books seldom help), I own 3 SRX's, I've owned an SRX since '02 and I bought my newest one (an '01) in 2011. I've had each apart and back together more times than I'd like to remember so suffice it to say I can fix them when something breaks, but I simply don't have a good enough understanding of clutching. I've searched and read a lot (as in hours and hours) of clutching posts but haven't found my specific issue, persay, so I'll do my best to describe it in hopes of getting a fresh perspective and some new ideas about how to improve it.
First, the good, my '01 has a pretty fresh top end (redone in 2013; compression is still 135+ across all 3), carbs are clean and set to specs, plugs are the right color, PV's set and operational, new Yamaha belt sitting a tad above secondary; pretty much everything "looks" right which, imho, means clutching is where I need to do some work. Stock gearing, good track; 1" lugs/144 studs, good bearings all around, stock secondary and a slightly modified primary with a thunder shift kit I've tinkered with since a couple years after getting my first SRX. In tight and wind'y trails, no one can get away from me, I come off the line and out of the corners great; I snap right up to 8600 RPM and stay there pretty well. When I'm riding lower MI trails I have a ton of fun, but that's not good enough because sometimes we hit a lake or head to the UP and then I feel like I'm giving up way too much to everyone else and it's just so damn frustrating!!!
So, onto my problem; I only climb quickly to 80 and then it takes a while to inch up toward 90, maybe 95 if there's enough trail. Yesterday we had nice mid twenty temps (cooler after dark), smooth trails and very few other riders so I was able to really pay attention to my gauges and here's what I experienced the whole 170 miles; as I'm climbing to speeds above 80, my tach slows down to about 8K telling me (with my limited understanding) that I have too much weight on the tips of my primary weights. Or is it; I mean could it be something else, could it be ANYthig else and if so what?
Additionally, when I back off to 3/4 to 2/3 throttle and cruise along at 60 to 70 and then go WOT, I only wind back up to an even 8K, she bogs a bit and won't climb nearly as high in speed. Only way to get back up in speed is to slow down to 50 and then go WOT and it acts the same as if I'd done it from a lauch; up to 8600 and then slowly back down. Again I ask, what could it be besides tip weight because based on what I'm seeing from other posts, I feel like I'm already too light out there as it is. Could this be a backshift issue? Could it be something else clutch related entirely?
Based on what I've read, I plan on using the sharpy trick to see how far they're moving and I plan to inspect the weights and rollers again to see if there's any wear, but I know they looked good last time I adjusted weights and I know my shims are tight so the weights aren't getting sloppy in there. I could take photos and/or report back with other findings, actual weight of weights, screws and washers, etc, but what I want to hear from you guys is where else to look and what else to consider so I can look at and hopefully eliminate some other variables.
As always...thanks in advance!
First, the good, my '01 has a pretty fresh top end (redone in 2013; compression is still 135+ across all 3), carbs are clean and set to specs, plugs are the right color, PV's set and operational, new Yamaha belt sitting a tad above secondary; pretty much everything "looks" right which, imho, means clutching is where I need to do some work. Stock gearing, good track; 1" lugs/144 studs, good bearings all around, stock secondary and a slightly modified primary with a thunder shift kit I've tinkered with since a couple years after getting my first SRX. In tight and wind'y trails, no one can get away from me, I come off the line and out of the corners great; I snap right up to 8600 RPM and stay there pretty well. When I'm riding lower MI trails I have a ton of fun, but that's not good enough because sometimes we hit a lake or head to the UP and then I feel like I'm giving up way too much to everyone else and it's just so damn frustrating!!!
So, onto my problem; I only climb quickly to 80 and then it takes a while to inch up toward 90, maybe 95 if there's enough trail. Yesterday we had nice mid twenty temps (cooler after dark), smooth trails and very few other riders so I was able to really pay attention to my gauges and here's what I experienced the whole 170 miles; as I'm climbing to speeds above 80, my tach slows down to about 8K telling me (with my limited understanding) that I have too much weight on the tips of my primary weights. Or is it; I mean could it be something else, could it be ANYthig else and if so what?
Additionally, when I back off to 3/4 to 2/3 throttle and cruise along at 60 to 70 and then go WOT, I only wind back up to an even 8K, she bogs a bit and won't climb nearly as high in speed. Only way to get back up in speed is to slow down to 50 and then go WOT and it acts the same as if I'd done it from a lauch; up to 8600 and then slowly back down. Again I ask, what could it be besides tip weight because based on what I'm seeing from other posts, I feel like I'm already too light out there as it is. Could this be a backshift issue? Could it be something else clutch related entirely?
Based on what I've read, I plan on using the sharpy trick to see how far they're moving and I plan to inspect the weights and rollers again to see if there's any wear, but I know they looked good last time I adjusted weights and I know my shims are tight so the weights aren't getting sloppy in there. I could take photos and/or report back with other findings, actual weight of weights, screws and washers, etc, but what I want to hear from you guys is where else to look and what else to consider so I can look at and hopefully eliminate some other variables.
As always...thanks in advance!
Youllbe2nd
New member
Any idea what helix you have in the secondary? Just to clarify, it hits 8600 then drops to 8000 rpm after 80? Can you clarify your exact primary setup, springs and wrap etc...how much weight in each hole of the weights? Need all the info. There's lots of good support on this forum your in the right place.
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Wizard
Member
Yes, you have it right; 8600, then 8000 after 80 mph. I'll document all the clutch specs tomorrow and report back.
sounds like your secondary isnt back shifting when you let off, look for a multi angle helix and fresh springs. I see somebody stated they are close to 8dn-20 profile, maybe start with a setup that works well with them w-w-w in primary with 51/45 and a green secondary at 60-70. Have you called thunder products?
Last edited:
Wizard
Member
Haven't called Thunder...started with you guys to get some feedback. Below is what I have, but I'm not certain about either spring...
Primary:
- Spring: white yellow white (I think - see photo) - 6mm wire diameter; 5-1/4 turns; ~92.5mm free length
- TSK Weights: 38.4g each; Hole 1= 5.8g, Hole 2 = 5.0g, Hole 3 = 4.2g
Secondary:
- Helix: 8BV71 = 47°
- Spring: Unknown; no markings; all black (see photo) - 5.25mm wire diameter; 5-1/2 turns - it might be the "red" spring but no way to be sure.
- Setting: 3-3 (60°)
Primary:
- Spring: white yellow white (I think - see photo) - 6mm wire diameter; 5-1/4 turns; ~92.5mm free length
- TSK Weights: 38.4g each; Hole 1= 5.8g, Hole 2 = 5.0g, Hole 3 = 4.2g
Secondary:
- Helix: 8BV71 = 47°
- Spring: Unknown; no markings; all black (see photo) - 5.25mm wire diameter; 5-1/2 turns - it might be the "red" spring but no way to be sure.
- Setting: 3-3 (60°)
its the helix finish angle, since its the straight 47, the engine cant pull the load on top with the extra tip weight and the 47 finish angle on the helix. you need to do ONE of the following to tune it out.
1.) remove tip weight from the primary weights
2.) use a multi angle helix with a 47 start and something like a 43 degree finish angle.
3.)use a primary spring with more total force, this will however slow your shift down, but raise the topend rpm.
anyone of the 3 will change the topend rpm, but its a testing process of trying different things to get the desired shift out result. if it were my sled, i would change the helix out to a multi angle as the results will be more noticeable and more then likely more desireable as the stock helix is just that, a stock helix and not really aggressive other then a straight 47 degree.
1.) remove tip weight from the primary weights
2.) use a multi angle helix with a 47 start and something like a 43 degree finish angle.
3.)use a primary spring with more total force, this will however slow your shift down, but raise the topend rpm.
anyone of the 3 will change the topend rpm, but its a testing process of trying different things to get the desired shift out result. if it were my sled, i would change the helix out to a multi angle as the results will be more noticeable and more then likely more desireable as the stock helix is just that, a stock helix and not really aggressive other then a straight 47 degree.
if anyone of your friends has a helix for you to try, get a 50/44 and retune the weights to that helix, youll find that one to work well and be really fun in the trails, great upshift and snappy backshift for on and off the gas in corners, will work well with your front weights. shoot for 8100rpm out of the gate and let it climb to 8500rpm after about 300-400ft out.
Youllbe2nd
New member
Bingo ^^
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Wizard
Member
Thanks, this confirms my thoughts; I was thinking more weight in hole 1, less in hole 3 AND multi angle on the secondary. I don't mind experimenting; I really want to get better at clutches. Anyway, I only have 1 guy nearby with Yammi stuff I plan to call. If he doesn't have multi angle helixes, where can I purchase them?
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Dalton is a great helix, and I think micro Belmont still sells helix for Yamaha.
the reason I go for the helix is you get a better bang for the buck that way.
your front clutch is upshifting and your back clutch "controls" the shift via the tension in the sec spring, the steeper the ramp angle is the more side pressure must be applied to maintain grip. the rear clutch is torq. sensing, so.. whats going on is you blip the throttle to wide open and it climbs to your 8600rpm on the upshift and the engine comes to peak, then rear clutch then senses a loss of torq at topend. This is because the torq from the engine has decreased as the peak hp comes up, this makes the rear clutch want to backshift and it fights the front clutch which is trying to upshift, so it kinda gets in a dead zone. It just makes noise and is low on rpm and doesn't really pull anymore.
the reason I go for the helix is you get a better bang for the buck that way.
your front clutch is upshifting and your back clutch "controls" the shift via the tension in the sec spring, the steeper the ramp angle is the more side pressure must be applied to maintain grip. the rear clutch is torq. sensing, so.. whats going on is you blip the throttle to wide open and it climbs to your 8600rpm on the upshift and the engine comes to peak, then rear clutch then senses a loss of torq at topend. This is because the torq from the engine has decreased as the peak hp comes up, this makes the rear clutch want to backshift and it fights the front clutch which is trying to upshift, so it kinda gets in a dead zone. It just makes noise and is low on rpm and doesn't really pull anymore.
Wizard
Member
As a preliminary try, I scrounged up some parts I had around and that left me with a question. My 98 SRX had a multi angle Bender helix and a green spring so I set it at 70° and threw it on. I'll likely change that to 80° and I'll call bender to see if they can tell me the angles based on the part number or serial number they put on it. I also found my stock 2001 700SRX primary and threw it on; it definitely has 8dn-20 weights, but I suspect it has the original rivets so I still need to change that.
My question is what are those rivets??? According to the tech pages they're 17.2 and 13.9, but what are those numbers; grams or something else?
I'm now shifting down around 8100 or 8200 but don't have a long enough run to see if it climbs after a while so I'll have to wait until I can get her out on the trails to see if it's what I want or not with these rivets.
My question is what are those rivets??? According to the tech pages they're 17.2 and 13.9, but what are those numbers; grams or something else?
I'm now shifting down around 8100 or 8200 but don't have a long enough run to see if it climbs after a while so I'll have to wait until I can get her out on the trails to see if it's what I want or not with these rivets.
Wizard
Member
Thanks...so now I'm wondering why everyone says to use both 4.5g rivets instead of leaving it how it is (4.5 and 3.6). What would adding .9g (x3 weights) do that's better than it is with the weights it came with; does it just keep it right on the top of the power curve for a few extra 100 feet; good for short lake runs but not noticeable trail riding or can it help even more than that?