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Discussion Starter #1
Hello. I'm not a regular here. I just came to read up on info about grom suspensions, brakes, and racing setups. I'm currently doing a very intensive build on a miniGP bike. I'm actually building the bike from scratch, and basing the sizing off of Honda Grom wheels and forks. Planning on using a Daytona 190cc motor. So far, I've bought forks, was given an R6 rear shock, have made the upper triple (waiting on aluminum for the lower triple, and 7075 to make the stem out of). I've gotten aluminum for making a sport bike-ish perimeter frame and swingarm, and just starting mocking something up with cardboard. Just wondering if any of you would be interested in seeing the build as I progress with it. I totally understand if you don't, seeing as it's not really grom.

As a teaser, I'll add a pic of the finished triple tree. Oval hole for the steering stem because I'm using inserts to make the fork offset adjustable. Cheers!

In3IuXR.jpg
 

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i'd be interested to see it.

you need a way to retain the insert in the top triple though. you should have included a pinch bolt.
 

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Discussion Starter #3
The insert will be reamed to fit the stem, and have a slit in one side. That hole you can see is for an M8 set screw. I also sized the flanges so the nut on the stem will squeeze the insert in. I haven't bored the insert yet, but I made a couple of those first to make sure I could. Here's a few pics of the triple tree in progress.

AsvDY0I.jpg

lFXUPWx.jpg
 

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I like to see other builders, DIY MC engineers and see how they do their builds, tools they use, Fuel manage system and how they figure the flow of A/F to their engine, alignment setup from counter sprocket to the rear sprocket setup and all the other good stuff that goes along for a special build.

Just remember one thing if you are using grom wheels, the 2013-14 wheels are lighter than the newer grom wheels and if you want to go lighter there is carbon fiber wheels.
 

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Post away man like most are saying we like this kinda stuff and pretty supportive of builds like it,,, with that said try not to do us like some before you offer a peak get the ball rolling and then never hear shit from them unless someone happens to stumble across their build and bumps it into active topics. Good luck Ride safe
 

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The insert will be reamed to fit the stem, and have a slit in one side. That hole you can see is for an M8 set screw. I also sized the flanges so the nut on the stem will squeeze the insert in. I haven't bored the insert yet, but I made a couple of those first to make sure I could. Here's a few pics of the triple tree in progress.

View attachment 77640

View attachment 77642

if you don't forcibly clamp the insert in the top clamp you are effectively uncoupling the top tree from the stem. i understand what you're doing and it probably wont matter on a bike this size, but the ONE thing that every adjustable tree set has is solid clamping of offset adjusting inserts.
 

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Discussion Starter #9
interesting build, sounds like your going for something like a ohvale. they also have a Daytona 190 option but its smaller than the grom
It's funny you say that. I have a pocket bike that I went nuts with mods on before. Started out as an x-19. Swingarm would twist if I tried to ride it fast. I reinforced the swingarm, then it would pogo. Swapped a Honda 954rr rear shock in. Modded the front springs, made preload spacers, and used much thicker oil to get it balanced. Put in a 125 4 speed. Modified the frame and made my own shifter, put on oversized brakes (have to unbolt the rotor to get the caliper off), made my own exhaust. You get the idea. I don't see the ohvale really having much over that pocket bike other than engine size. I'm just over 6', and while the pocket bike is fun, it isn't comfortable by any stretch. Now that Ohvale's are getting imported and going to show up in miniGP, I want a bike I can use to compete with them, but I want it more like a grom size. Thus, a custom aluminum perimeter frame sport bike using the same engine, with 12" wheels.
 

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It's funny you say that. I have a pocket bike that I went nuts with mods on before. Started out as an x-19. Swingarm would twist if I tried to ride it fast. I reinforced the swingarm, then it would pogo. Swapped a Honda 954rr rear shock in. Modded the front springs, made preload spacers, and used much thicker oil to get it balanced. Put in a 125 4 speed. Modified the frame and made my own shifter, put on oversized brakes (have to unbolt the rotor to get the caliper off), made my own exhaust. You get the idea. I don't see the ohvale really having much over that pocket bike other than engine size. I'm just over 6', and while the pocket bike is fun, it isn't comfortable by any stretch. Now that Ohvale's are getting imported and going to show up in miniGP, I want a bike I can use to compete with them, but I want it more like a grom size. Thus, a custom aluminum perimeter frame sport bike using the same engine, with 12" wheels.
I like where your going with it on the size

Seen a couple of the ohvale's at our last miniGP race, they look sharp and from what I hear they handle great, hope to throw a leg over one next season just to see what there like but I still prefer a motard.....even over the grom
 

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Discussion Starter #11
I guess I'll bring this up to date for where I am so far. First off, I'm recovering from shoulder surgery, unrelated to riding. That's why I've had time recently to work on this, and it's what I'm doing to fill my time. Making that triple tree was my first project out in my shop, and I'm using this as a way to ease back into going back to work. I know someone posted about being interested in the processes and tools used as well, so I'll start off with that. For my machining, I've got an old 1hp J-head Bridgeport milling machine. I also have a Jet 9x20 metal lathe.

z7RSRWO.jpg

5Jwphad.jpg

I had to make a fixture plate for my small rotary table to be able to make the oval inserts for the adjustable triple trees. It worked really well.

QxA5BLX.jpg

j8zeET5.jpg

And, since I'm waiting on other material, I started mocking up a frame. I'm going to be using 1"x3" aluminum tubing with radius corners, 1/8" wall thickness. I had an empty TV box, so I made some good approximation of 1"x3" tubing and started making some pie cuts and taping. I'm not trying to be super accurate here, it's cardboard after all. That said, the lunch box I set the forks on actually have the axle at pretty close to the right height. I measured the angles, and they're only off by about 1 degree, as measured with an old fashioned compass and flat things like walls (that aren't actually very accurate in buildings). Obviously, I'm going to cut the vertical pieces and not have them going to the ground, but still just mocking it up for now.

8sjTLVF.jpg

g4Wh4V7.jpg

Also, thank you for pointing out that the 13-14 wheels are lighter. I'm probably going to have the buy the wheels sooner than later, especially so I can make the swingarm, and then get the side to side measurements on the engine correct for sprocket alignment. I'm contemplating trying to make the swingarm pivot adjustable as well, but I haven't quite visualized how that would work with keeping things lined up with the front sprocket. Things to think about. Once I'm a little more through the mocking up phase on the main frame, then I'll set about making a jig to hold the head tube, and have positive stops to clamp the aluminum tubing to before welding.

Also, I've had lots of years of tinkering and fixing and modding, but I am by no means an expert or an official engineer. If you see something that concerns you, or there's a better way, let me know. I still think I'll be fine on the inserts for the adjustable offset. The insert is as tight of a sliding fit as can be without becoming an actual press fit. Once the hole is bored, it will be a similar snug sliding fit, with a cut through the side similar to how the fork tubes get clamped. Then a set screw in the triple tree will push the oval part to clamp that, also effectively locking side to side, and front to back, and then the stem nuts will pinch the pieces together with the flange, similar to pre-tensioning tapered bearings. I'm confident it'll work fine. At least, confident enough to act like it until I actually get everything bolted together. :-D
 

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hey man props to you for doing it all manually. when it comes to custom parts i try to stick to conventions, they are there for a reason.



all the custom work i do is modeled in CAD (by me) then machined with CNC mills and lathes (sometimes by me, often by my machinist). i wouldn't stand a chance on a manual (i'm not a machinist, i'm an electrician with an interest in machining). i have a friend with a machine shop, i do his electrical work and he lets me play on the machines.
 

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Discussion Starter #13
I wish I could do CNC. I have a smaller x2 mini mill. I've been contemplating the idea of turning it into CNC just to play with. That said, it's the CAD/CAM that I struggle with. I've attempted to start putting the parts I'm making into Fusion 360. I find it to be very frustrating software. I'm sure it's my lack of knowledge with it, but still.

Anyway, I've started working on doing a little of the tig welding on some aluminum. Maybe I'll have something to show for my efforts soon.
 

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On the 2013-14-15 grom wheels you can make it a little lighter by removing the black paint and polishing the wheels which is cheaper than buying a carbon fiber wheel. Also going hy-bird ceramic bearings for the wheel bearings is ok but make sure you get USA made bearings and no Chinese hy-bird ceramic bearing and the rear wheel has 3 bearings which the third one goes to the rear hub/sprocket unit and make sure to use good old steel ball bearings for this unit, both of my groms that are heavily modified had that sprocket/hub hy-brid ceramic bearing on this hub unit go out big time I think the hub/sprocket hy-bird ceramic bearings can't handle the side thrust load and causing the steel housing to wear faster causing the ceramic bearing to come loose.

Also to reduce drag on the wheels we are using speed spacers which is just a wheel spacers that has the area around the contact to the wheel dust seal machined a few thousands of mm to reduce drag on the wheel to dust seal, you can do the same by taking the stock wheel spacer and marking the area close to the contact area of dust seal and machine that area around the thickness of the dust seal to reduce drag. The old Harley drag racers use to just remove the wheel dust seal just to remove drag.

good luck on your build just take your time and document and wt everything you build just so you know what your total time and weight of each part is going to be for future reference. I sort of did that on my builds since my first mods in 2014 till now so I can see what improvements or failure on changes have done to the groms performance.

One more item I see you are going to use the 190cc engine, those engines are great but I believe they are 2v setup and not 4v setup. For me all the grom engines that have produced the most torque and hp have been 4v engines using either a Koso 170-4v head or a 181-4v takegawa head with heavy porting, unless you are getting the daytona Anima 190-4v flx engine with decompression cam which is around $1300 and only 4 speed and carb setup.
Good luck.
 

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I wish I could do CNC. I have a smaller x2 mini mill. I've been contemplating the idea of turning it into CNC just to play with. That said, it's the CAD/CAM that I struggle with. I've attempted to start putting the parts I'm making into Fusion 360. I find it to be very frustrating software. I'm sure it's my lack of knowledge with it, but still.

Anyway, I've started working on doing a little of the tig welding on some aluminum. Maybe I'll have something to show for my efforts soon.
i'm completely self taught in fusion and found it very simple to use. i wanted my machinist to build parts for my rc51 and he said he'd do it if i drew them. i'd model the part and he'd tell me it was total shit, and i'd have to do it again. make no mistake, i'm an electrician and bike builder hobbyist, and i managed. here are a few of the parts i've managed to draw up. the triples never came to fruition as my friend was simply too busy to do them. but it was a great exercise in learning how to model mutltiple components and join them into an assembly.

the switch housings i produced about 40 of them. i have them on my rc51 as well as my grom, and have sold 25 or so to other rc51 owners. that project worked out quite well.
 

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Discussion Starter #16
On the 2013-14-15 grom wheels you can make it a little lighter by removing the black paint and polishing the wheels which is cheaper than buying a carbon fiber wheel. Also going hy-bird ceramic bearings for the wheel bearings is ok but make sure you get USA made bearings and no Chinese hy-bird ceramic bearing and the rear wheel has 3 bearings which the third one goes to the rear hub/sprocket unit and make sure to use good old steel ball bearings for this unit, both of my groms that are heavily modified had that sprocket/hub hy-brid ceramic bearing on this hub unit go out big time I think the hub/sprocket hy-bird ceramic bearings can't handle the side thrust load and causing the steel housing to wear faster causing the ceramic bearing to come loose.

Also to reduce drag on the wheels we are using speed spacers which is just a wheel spacers that has the area around the contact to the wheel dust seal machined a few thousands of mm to reduce drag on the wheel to dust seal, you can do the same by taking the stock wheel spacer and marking the area close to the contact area of dust seal and machine that area around the thickness of the dust seal to reduce drag. The old Harley drag racers use to just remove the wheel dust seal just to remove drag.

good luck on your build just take your time and document and wt everything you build just so you know what your total time and weight of each part is going to be for future reference. I sort of did that on my builds since my first mods in 2014 till now so I can see what improvements or failure on changes have done to the groms performance.

One more item I see you are going to use the 190cc engine, those engines are great but I believe they are 2v setup and not 4v setup. For me all the grom engines that have produced the most torque and hp have been 4v engines using either a Koso 170-4v head or a 181-4v takegawa head with heavy porting, unless you are getting the daytona Anima 190-4v flx engine with decompression cam which is around $1300 and only 4 speed and carb setup.
Good luck.
There is a LOT of good information in here. I really appreciate it. There was a set of wheels on ebay which happened to be 2014's, so I have those on the way. I'd really love to try carbon fiber wheels, but that seems a bit excessive on what is so far a theoretical and experimental bike. When I get it done and test it, if it works really well, maybe it'll be worth it at that point. CF for slicks, the regular wheels for wet tires maybe. If I had to guess on the sprocket carrier bearing, it'd be that there's only one bearing, and it probably sees a twisting torque on it due to being pulled by the chain. Sure, there are spacers to lock the inner races together, and the cush drive, but there's a lot of room for very irregular and inconsistent directions for torque to be applied.

I am planning on getting the Daytona Anima 190 FLX or FDX. It's a 4v setup. It's intriguing thinking about what it would take to install the various sensors to get FI working on it, but I'm so good with tuning carbs, it would be wasted effort. Plus, in racing the crf150f, I had done a LOT of engine work to it. Lightened flywheel, crankshaft, and cam, bigger cam, high compression piston, milled the head, ported it, undercut the intake valve. What I can say is that doubling the output of an engine, and running it at high rpms, is detrimental to the lifespan of the engine. I get it, racing is harsh. That said, I've abused the hell out of a $230 Lifan 125cc in the monster pocket bike I built. Like, downshifting like the supermoto and backing it into turns, misshifting when getting used to GP style shifting, no maintenance, full throttle shifting and pulling wheelies going into every gear. I even managed to shatter a front wheel while backing it in once. That engine has taken it and just kept going. What I like about the Daytona is that it's a well designed motor, putting out the power without having to do crazy internal work to it. If the bike works really well, I'd consider buying a 2nd motor just to have with me in case of failure. In that case, it's nice to just have a crate motor, no mods needed.
 

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Discussion Starter #17 (Edited)
Taking a short break to let the steering stem cool down before the last pass or two getting the size on the lower triple area. When getting to the nearest thousandth, thermal expansion matters. Anyway, I got a little bit of the cutting, bending, welding done for the frame tubes. For the cuts I did, I used a saw that worked really well, but it won't work for the next few pie cuts that are on different sides to make the bends for the vertical portions. Picked up some new blades for the saw I'll use for those cuts today. In the mean time, I've made the headstock. I decided before finishing the vertical sections completely, I should finish the triple trees and be able to mount up the forks. Then, use a flat surface and make a couple jigs to bolt the forks at the front axles, and vertical portion of the frame at the swingarm mounts so that things don't get pulled out of alignment with the welding. It may mean that I'm sacrificing steering bearings just to fit for welding, but that's better than things going wonky on me. Might change my mind before welding, and just make a frame specific jig, but at the very least, it gives me time while working on other parts to think it through some more.

On to the pics! Frame progress so far:
View attachment 77736

Close up of the headstock.


Steering stem in progress.
eA6PH1d.jpg

Inserts finished.
Z4bOpZ9.jpg

And lastly, how it all fits together, minus the nuts. Oh, I already have some 7075 bored with the internal threads cut to make the nuts with as well. Just need to figure out how fancy I want to make them. M24x1.5 for upper and lower nuts, M26x1.5 for the nut between the bearing and the upper triple.
vAT3vq7.jpg

Even with just a quarter turn of the set screw, those pieces are locked together with no play, and that's without tension from nuts pressing the flanges together.

Also, a disclaimer - at this point, when I say finished, I just mean with the fabrication portion of it. At this point, I'm intending to get things anodized, so I'll actually spend more time with finishing grade sand paper and polishing at a later time.

2nd disclaimer - the injury on my thumb is actually a small bacon grease burn. Cooking is dangerous, play with motorcycles and machine tools instead!
 

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Can I be your newest best friend? We could hang out together and you can help me make stuff...!!! :eek:ccasion14::icon_king:

Seriously, you have some mad skills & the machines to bring your thoughts to life.

Keep posting, good stuff!
 

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looking good man. my winter project involves much less machining and much more welding. but i couldn't bring myself to build an entire frame.


interested to see how the frame turns out when finished.
 

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Discussion Starter #20
For a few reasons, motivation has been difficult to find for a few days. Started a side work project to help fund the engine purchase, and broke the valve for the cylinder for my shop press. Figures. I've been wanting to upgrade the cylinder anyway. I had a bearing start making noise in the gearbox for the leadscrew for my lathe feed. Parts are on the way for that. The next parts I want to make for this bike are going to need to be threaded on the lathe too. I'm stealing the idea for the swingarm pivot from real sport bikes that use thrust bearings, and a threaded sleeve on one side of the frame to sandwich the swingarm between the frame sides. I want to make the inserts for the frame, and that threaded sleeve. Also have bearings and hollow tubing for making the pivot shaft.

Before the change in pace, I finished making nuts for the top and bottom of the steering stem, along with the flat nut for going between the top bearing and the upper triple. When the shop press hydraulics went out, I switched pace, and did the pie cuts/welding for bending the frame for the vertical sections. I have it mocked up with the frame and headstock upside down for measuring.

ywwLwz0.jpg

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