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Discussion in 'Motorized Bicycle General Discussion' started by mapbike, Mar 10, 2011.
Just ordered my strip of material, it ships tomorrow
The question is - who's got a CNC machine and is willing to cut a few hundred of them?
The function of a clutch can be broken down to a few simple components...
The Friction material and its specific friction coefficent in cold and hot conditions.
The surface area of the contacting friction material to a hard surface.
The number of contacting surfaces.
And the force applied to the compress the friction materials to the hard surfaces.
Chances are that the modifications to the motors have pushed the torque of the motor beyond the clutches functional range...
Thus, the higher friction coeffecent materials wont be effective without greater applied force.
You guys might want to look for stronger springs!
I have read that some folks have switched to an automotive valve spring. Apparently they make for a good replacement after the factory spring looses it's tension.
Bairdco already tried some new pucks and it fixed his issues completely. The stock "friction" material is junk. An upgrade to real friction material will definitely help.
yes running different material will make an improvement along with what the other guy was saying of the clamping force.
the two parts on the clutch that are responsible for the link up are the clutch disc (in this case the gear with the pucks) and the pressure plate (the disc)
normally on a car these two can be upgraded to handle 800+hp using dual, even triple disc clutch packs. however....
these motors are limited to what is REALISTICALLY possible.
sure you could replace the factory spring with a valve spring, but are you actually gonna be able to pull that clutch handle? or will that cable keep from snapping?
these bikes should have come with something that is ACTUAL friction material rather than the wanna be stuff they gave us.
No issue with getting stronger spring, but I just wanted to add that I have made up some pucks from an industrial friction material, the ones that Bairdco has are one of the sets I made and I had an engine that the clutch slipped in real bad when trying to start it and all I did was to put the pucks I made in it and bam........no more slippage I didnt even have to adjust the clutch spring tension on mine.
I will admit that if I had adjusted the spring tension it would have mad it engage even better but mine is just fine like it is without messing with the spring so far aftera few hundred miles.
A better friction material even under the same pressure will hold much better, it takes more pressure with a lesser material for the clutch to work without slipping, the pressure is important of coarse but some of these engine do put a lot of presure on the the stock pucks but after they get so hot that the material sorta crystalizes they just dont hold good anymore and when the better material is used they work fine undre that same pressure because the original pressure wasn't the problem, it was that the friction material was lacking the ability to grip the clutch plate.
Just got some of the mcmaster material for my square puck clutch and made a batch. Also blued and heat hardened the pressure plate and grooved it with a cutoff for more friction. I'll report my results soon
How did you cut the material?
Also, I will be glad to hear your results!
Cut it with a hack saw, then I painstakingly filed one until it was perfect, then I traced the perfect one onto the other 14 blanks I made and cut any major oddness in shape with the hacksaw and did filing to fine tune them. All in all, the pucks took me about 2 hours I'll have results once my stud stops stripping, but it's the SECOND time the JB weld has failed to harden so I can't secure the head onto my engine yet. The folks were really nice about sending me free JB weld, but I won't have the bike fixed until two weekends from now Darn
Quick screwing with the JB Weld and put a Heli coil in that hole and be done with it LS614, I like JB Weld for some things but not for that.
Amazon.com: Helicoil 5546-8 M8 x 1.25 Metric Coarse Thread Repair Kit: Automotive
I had the 3rd set of mapbike's pucks. They worked flawlessly. The motor has a Puch Hi-Compression head and around 11.5:1 compression ratio. Stock pucks were trashed in no time. The difference was night-and-day. no more slipping when starting and the bike wanted to do wheelies. Never had that with the stock pucks. They bed themselves fast and really little dust was generated and that was at the outset when they were breaking in. After the first inspection I did the dust was less apparent. I would make regular checks and clean and re-grease the gears often, the grease tends to trap the loose dust.
I'd have more to report but my Chinee stuff let me down for the last time and the parts are all gone. Just need to get to the post office and get the last of them shipped with the clutch pucks going to Portugal
mapbike, will they fit with the tolerances of an HT block? that's my only real concern. Thanks.
If you're refering to the thickness of the pucks yes they fit just fine.
Is the material you are using 1/4"?
If it is 1/4" thick you'll have NO clearance issues.
No no, sorry, I already made pucks, and those are fine, I meant will the helicoils fit. have other people used them? I just don't want to go straight through the side of my crankcase with some enormous drill bit
I forgot about the heli coils, honestly I haven't used them on any of my engines because I haven't had anything strip out, but the bit that's required to drill the hole out isn't usaully that much bigger than the hole so I would think you should have plenty of room to drill it and install the heli coil.
I would also put loctite on that coil before inserting it if you do go that route, just a little extar insurance for a secure set of threads.....
I just went and looked at an HT case I have and it looks like you should have enough of room to drill for the heli coils, I'm not for sure what size drill bit is neccesary for the 8mm thread inserts but from what I can find you will need a bit size of about 8.4mm to drill the hole initially so that doesn't seem to me that it would be on the outer limits of the case.
I will list the tap size first. Followed by drill sizes. The drill size is for cut taps. These are for the "nominal" hole diameter required, nominal being midway between the upper and lower tolerance limits for the minor diameter.
These are the drill sizes needed for heli coil inserts for metric bolts or studs.
Size_______________ Drill size
M2.5 - .45 __________#37 drill
M3 - .5 _____________1/8 drill
M4 - .7 _____________#19 drill
M5 - .8 ______________#5 drill
M6 - 1 ___________6.3mm drill
M8 - 1.25 _________8.4mm drill
M10 - 1.5 _____________Z drill
M12 - 1.75 _______12.5mm drill
M16 - 2 __________16.5mm drill
Use some type of cutting fluid.
The Heli coil OD is ~ 10mm, i.d. is 8mm, both are 1.25 thread pitch inside and out, so the 10mm metric fine tap plus a Heli coil insert yields an 8mm metric coarse threaded hole.
Here's the best info. I can come up with that may help you decide if you have enough room for drilling for the Heli Coil, I think it should work just fine but a little measuring will tell the truth of it so I hope this helps.
I measured some of my bits and here is the results I have fur ya...
The 8.4mm bit measures roughly 0.330/0.332 I think you could get away with drilling that hole with a Q size bit which if I remember right measures 0.328/0.329 somewhere in that range.
Sorry to be jacking this thread but thank you SO MUCH for the help I'm surprised that the hole only needs to be 8.4 mm, but I guess the tap will take away the rest of the excess metal. My dad's work has a lot of machinists who do helicoils, so I may consult them just to be safe. Thanks for all the help, really I think I'll get my engine working eventually
Yes that would be a great idea, the info I listed in the last post was what I found on another forum where some people were discusing the same topic of heli coilling an 8mm hole and what drill size was needed, the 8.4mm bit sounds a bit small to me also but I'm not used to messing with metrics that much I've mainly always dealt with SAE stuff.
YES check with the machinist before you start drilling that case just to be sure,
When you do have the facts post it here or PM me I would like to know for sure myself just in case what I found is faulty info.
Will do, It will be a great day when I defeat this stupid stripped hole and I'll be happy to share Thanks again!
Hey LS614 I just seen the flaw in what I said in the bit size.....
If the heli coil is 10mm OD then you need to drill the hole for the 10mm threaded insert and not for the 8mm, the 8.4mm drill is for drilling a previously undrilled piece of material and then adding threads to it which requires a 8.4mm drill bit for the 8mm tap....
Quote: The Heli coil OD is ~ 10mm, i.d. is 8mm, both are 1.25 thread pitch inside and out, so the 10mm metric fine tap plus a Heli coil insert yields an 8mm metric coarse threaded hole.
here is where I messed up in my thinking on this earlier so you may not have enough room on the case for that big of a drill.........so yes take the engine to the machinist and make sure that it can be done without trashing the case.