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Post by larry001964 on Feb 27, 2012 21:34:34 GMT -5
Well it ain't pretty, but it's done.  Ill worry about prettying it up and making other cooling mods later, I don't have a dremel tool so cutting with the tools i have is a bit limited.. However this should work. |
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Post by mainepeace on Feb 27, 2012 21:36:36 GMT -5
I'm sure you can make it look pretty nice when you're through. Just make sure you have a drainage hole at the lowest point in case some rain Does get in there. Hope it works for you.
Greg
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Post by larry001964 on Feb 27, 2012 21:47:52 GMT -5
Well I'm planning on cutting out the cross part i have on for now, and placing a wire mesh over the hole, will provide cooling but aid in keeping the rain out, I think scootertech has this idea as his avatar..
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Post by dude on Feb 27, 2012 22:04:51 GMT -5
I have drilled a few holes in my Zuma cover (no cooling vent at all factory). I have been in some heavy rain and have felt very little slipage. Is there a bigger or a better fan?
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Post by mainepeace on Mar 3, 2012 22:32:38 GMT -5
There are "performance" fans out there, but they don't seem to flow more than the stock one. Just remove a few of the fan blades and you'll get more airflow. BTW, we now carry a nice all chrome CVT cover with nice holes already cut in it.  Unfortunately it's for the Gy6. Greg |
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Post by larry001964 on May 27, 2012 10:16:00 GMT -5
Just an update Fawkes is running well. Had to modify the variator ramp plate to handle the power since then no issues. I will post these mod later so all can see..
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Post by timelancer on May 28, 2012 0:47:23 GMT -5
I would recheck your calculations, a shorter connecting rod means the piston travels further down in the cylinder from the larger stroke, just a guess tho.
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Post by larry001964 on May 28, 2012 5:51:24 GMT -5
I would recheck your calculations, a shorter connecting rod means the piston travels further down in the cylinder from the larger stroke, just a guess tho. It does travel farther down the cylinder.. My calculations are based on how many mm my piston traveled over what the stock cranks travel was, not what is advertized by Hoca.. My piston travels .50 mm farther up and down the cylinder than stock. And this figure does not account for the cc added by the Big Bore head.. |
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Post by larry001964 on Jun 19, 2012 21:21:40 GMT -5
Here's the finial piece of the stroker mod. As many know i was having problems with the the Variator handling the power of the stroker. Tearing up variators.. What i concluded was the thickness of the ramp plate ( made of steel ) due to the increase in power was cutting thru the key guides then thru the aluminum guide fingers on the variator. My fix was to increase the thickness of the Ramp plate at the keyguide area so the stress was displaced over a larger area.. Here is my fix  Had to build up the thickness of the ramp plate with a welder  Ramp Plate increased thickness from 2.3mm to 4.5mm  Custom Key Guides Cut from hard plastic using dremel  Finished Variator ;D As of now i have over 1000 miles on the new custom set up with no signs of cutting thru the plastic keys... This is the conclusion of the stroker crank thread.. Fawkes is now a daily driver and I completely enjoy driving him. I hope every one enjoyed reading this mod and hopefully others will improve on my work :-) .. |
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Post by mainepeace on Jun 20, 2012 3:33:09 GMT -5
What an inventive solution! So if the right part isn't available, just make it yourself! Kudos to you!
Greg
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Post by larry001964 on Jul 17, 2012 19:21:09 GMT -5
Hi Guys,
Well today i blew my CVT setup again, still apparently getting too hot.. Not sure now what to do.. this failure is different than before, the variator and its keys seem to prevent damage to the guides on the vairatior. that part is fine..
It's the Hoca drive face that took the damage, the inner grooves that fit over the splines on the crankshaft are completely routed out smooth.. will have to give more thought to this, my cooling fan is melted again,..
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Post by larry001964 on Jul 23, 2012 20:18:00 GMT -5
Well Guy's here's the damage... Plastic Cooling fan (whats left of it)   Damage to drive face ( This was a Hoca, and to be honest I'm not happy with the quality, it's made of aluminum not steel, but the crankshaft splines are fine...     This is what happens when that silly plastic cooling fan melts, it loosens up the works and the stroker just tears up the rest... Believe it or not I think i feel another mod coming on to solve this issue... It's very unconventional.. but to give every one a clue it involves a metal squirrel cage fan instead of the crappy plastic fan.. I do believe the extra heat I'm dealing with is being generated by two issues, the drive belt pressing harder on the variator because of the higher speeds generating more heat that is not being properly dissipated and the 85cc bbk.. Since many others have had over heating problems with their CVT I'm wondering if I should post the next mod in this thread or start a new... Opinions ? |
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Post by bonnietonton on Jul 24, 2012 9:55:46 GMT -5
Your engine is bigger and hotter now. I noticed this when I upped mine to 50mm. So you need more cooling of the engine. The cvt is attached right next to the engine. Heck the variator sits on the crank itself. So of course it's going to have a lot of heat. You would also want more air to enter into the front of the cvt cover. I noticed the front is hotter than the back of the cvt cover. Try this 49ccscoot.proboards.com/index.cgi?board=gentech&action=display&thread=394I'm thinking about doing this but just lazy now. I noticed my cvt cover is hotter with the upgrade. I hope this helps. |
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Post by noday on Jul 24, 2012 12:56:43 GMT -5
I do not think this is a primary heat problem.
It is a belt slip problem. All of the engine torque is transmitted from the crank to ONLY THE FIXED FACE of the variator. the moving face is free wheeling & pushes against the belt, but is not connected to the crank itself. the belt slip is causing the heat.
The small teeth of the fixed face are not holding up to the forces of your engine.
if you look at known high torque motors, like the 2Ts, jog 50 variants, you will notice that they have a splined shaft & the variator ramp plate has teeth to fit the splines. the driving torque is transmitted to both faces of the variator.
I think you are beyond the force levels that the 139qmb was designed to operate under with the small splines and a single driving face.
maybe you could fabricate a steel toothed insert similar to the style used on the 1E40QMB engine to reinforce the variator fixed plate.
too bad Hoca did not forsee this problem and use a splined shaft on the variator side of the crankshaft.
good luck.
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Post by larry001964 on Jul 24, 2012 15:20:42 GMT -5
I do not think this is a primary heat problem. It is a belt slip problem. All of the engine torque is transmitted from the crank to ONLY THE FIXED FACE of the variator. the moving face is free wheeling & pushes against the belt, but is not connected to the crank itself. the belt slip is causing the heat. The small teeth of the fixed face are not holding up to the forces of your engine. if you look at known high torque motors, like the 2Ts, jog 50 variants, you will notice that they have a splined shaft & the variator ramp plate has teeth to fit the splines. the driving torque is transmitted to both faces of the variator. I think you are beyond the force levels that the 139qmb was designed to operate under with the small splines and a single driving face. maybe you could fabricate a steel toothed insert similar to the style used on the 1E40QMB engine to reinforce the variator fixed plate. too bad Hoca did not forsee this problem and use a splined shaft on the variator side of the crankshaft. good luck. Actually I had thought of that, just not sure yet how to address that.. I'm in the process of building a better cooling system for the CVT right now, perhaps ill also address that issue too while I'm at it.. |
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Post by larry001964 on Aug 3, 2012 7:25:49 GMT -5
Well today i snapped my Gates Powerlink belt after 1600 miles of driving. Cant begin to express my fustration. Im getting tired of so many custom repairs..
If i had access to a machine shop all the time, it might be different.
What im thinking now is keeping the stroker but downgrading the jug and piston to a 72. Dont know if i can use the 50 mm head or not but i really need to lower the power so i can use standard qmb parts. And not tear them up
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Post by viral on Aug 3, 2012 8:37:07 GMT -5
That's exactly why I'm just using a 72cc kit. A buddy of mine has an 83cc with big valve head, big carb, camshaft etc but he's constantly having problems with it especially overheating.
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Post by larry001964 on Aug 3, 2012 8:55:04 GMT -5
My main concern is can i use the 50mm head on a 72 jug?
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Post by viral on Aug 3, 2012 9:01:37 GMT -5
I'm not sure. I imagine it would work, but wouldn't you get lower compression possibly even power loss from using a head bigger than the cylinder?
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Post by larry001964 on Aug 3, 2012 9:13:08 GMT -5
I'm not sure. I imagine it would work, but wouldn't you get lower compression possibly even power loss from using a head bigger than the cylinder? Im thinking so, but i also thinking the crank would compasate and i already know i cant use the stock head, the piston hits the valves. I paid almost 200 for that crank i would like to use it. |
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Post by viral on Aug 3, 2012 9:15:20 GMT -5
Well, only one way to know for sure, try it out and see. I can't imagine any reason it could damage the engine. Just my opinion based on no factual evidence whatsoever  |
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Post by larry001964 on Aug 3, 2012 9:17:33 GMT -5
Well, only one way to know for sure, try it out and see. I can't imagine any reason it could damage the engine. Just my opinion based on no factual evidence whatsoever Lol |
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Post by millsc on Aug 3, 2012 9:19:17 GMT -5
bet it hauled when you had it running right
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Post by larry001964 on Aug 3, 2012 9:31:01 GMT -5
bet it hauled when you had it running right Ohhh it really does, Fawkes gives up ground to almost nobody easly, part of me hates to downgrade, but i need a daily driver. |
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Post by millsc on Aug 3, 2012 10:06:39 GMT -5
quite the impressive list of parts hope you get it running regular
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Post by larry001964 on Aug 3, 2012 18:25:54 GMT -5
Ok One more try I think before downgrading the power, Fawkes is actually running soooo good i hate to give up on this when I'm sooooo close..
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Post by dagger75 on Aug 3, 2012 21:48:39 GMT -5
What about gearing it up another couple teeth Larry? May help it get the power to the ground better and less "torque" at low speeds. Could always get a stiffer torque spring if you lose anything on hills etc. Would be able to cruise at much lower Rpms which should be easier on the whole drive train. Can't you Up both Primary and Secondary gears?
I appreciate your effort and time giving us this walkthru of your Stroker experience. Take care
Gary
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Post by OverReved on Aug 3, 2012 23:15:12 GMT -5
Only reason I know of for snapping so many belts is because your front or back belt ramps are not true, less to do with "power". Have you done a check for run-out on the variator with no belt installed and also on your clutch at the rear? Both the driven and drive faces need to be checked.
If you've neglected to check please also look at the run-out on your crankshaft and also the final drive input shaft while you are there, and give both a good jostle to make sure you don't have a loose bearing.
Have you considered a shorter belt? Yours could be too "loose" and the non tensioned side could be slapping the inside of the CVT cover under acceleration or high speed cruising.
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Post by millsc on Aug 3, 2012 23:29:13 GMT -5
i say keep trying you dont need help im sure you will get it props on one bad scoot ride on
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Post by noday on Aug 4, 2012 6:15:56 GMT -5
a few things I would try. reinforce the var fixed face by drilling 4 holes in both the start ratchet and var fixed face about 3/16" diameter or so  make sure the teeth are aligned then weld 4 short steel pegs in the holes in the start ratchet. this should reinforce the grip of the fixed face to the crank and stop the stripping of the fixed face teeth. next I would drop the compression ratio down to around 9-9.5 by enlarging the combustion chamber slightly. you should only need a CC or so. you can either dremel the space in the head or sand the top of the piston a bit. this should make it easier to start & let you get rid of 1 of the batteries and over all weight. maybe even shorten the variator boss and put in a washer to decrease belt travel up the variator face. you will lose a bit of top speed, but also decrease the forces working on that single drive face. good luck Larry PS: edit added The cheapest and easiest thing to do may be to go back to a generic steel drive face rather than mod the kick start ratchet another option is to try adding a no slip washer, something like a SUR-LOCK www.industrialbolt.com/downloads/Washers.pdf |
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