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Post by 90GTVert on Apr 28, 2024 9:55:45 GMT -5
I ordered a whole new top end from ScooterTuning.Ca, so that'll be here in a couple of days. They didn't have wrist pin bearings, so those are coming from ScooterPartsCo and will probably be at least a week.
I think I'm gonna get it together again and put the 28mm VHST back on. With the car show and small bore coming up, I don't want to risk more pistons trying to sort out the PWK. This is about like the Lectron on the TPR. 2 pistons and I'm over it. In this case, I want to figure it out. It seems so close. Could be that it would work and the worn cylinder gave me trouble or maybe the conrod really can't be out of round at all. If it acts up like this with a new kit and the 28mm, then I'll have to assume the rod is a problem. I really don't think the timing is it anymore. It bugs me that it ran well for 4 passes in a row. Then the next time it went out it acted like the tune was off at WOT, but still ran hard and did good times for one 1/8 and then failed. It just feels like it's right there and 1 thing somewhere is getting me.
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Post by 90GTVert on May 6, 2024 11:04:51 GMT -5
Off to a great start. I just opened the new top end. One big positive for me was maybe I could use more commonly stocked A pistons with a new kit. New kit is already AA out of the box. š¤¦āāļø I know itās common practice and the TPR came as a B new once, but what sucks is that everyone doesnāt bother to stock other sizes.
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Post by 90GTVert on May 6, 2024 15:13:51 GMT -5
I took a bunch of measurements of the new kit.
The AA piston measures 2.0446" for me. The new A was 2.0444" by me. That's 51.928mm for the A and 51.933 for the AA by my measurements, which makes the AA 0.005mm larger exactly as it's supposed to be. That's a relief for me since other info that I have is contradictory to things I've measured.
The bore measures from 2.0474"/2.0477"/2.0478" (top/mid/bottom). The new A kit measured 2.0472"/2.0475"/2.0478". Both go up 0.0003" from near the top to below the ports, but meet at the same measurement near the bottom.
This creates a minimum clearance of 0.0028" or 0.071mm for both the AA and A kits when new. This is where it's weird for me. The measurements make sense, as they seem to match what they're after for clearance in both cases. However, Malossi states 0.048-0.056mm for a clearance spec. Gary from G-Force told me they use 0.045-0.055mm. Gary also said that he's never seen anyone need a C piston before. By my measurements, I would need to reduce clearance by 0.023-0.015mm to meet Malossi's spec... that would mean a BB to CC piston... new out of the box for the A or AA kits. Roughly the same for Gary's specs.
At this point I have to assume that I don't know how to measure. I'm not dumb enough to think I'm a pro with pro tools. I just know that I spend a lot of time on it and try to be as accurate as I can. My piston measurements at least match where I'd expect and the cylinder clearance specs match the other I had new. I can't be way way off... but maybe I'm doing something wrong. It's either that or the pros at Malossi and G-Force's machine shop are doing something different than the specs they provide. If I were way off, the C piston should have seized. It did that at the end with the PWK... but it ran fine 800 miles prior. Others in comments have told me that they also had more clearance than spec as I did.
Whatever the case may be, collecting all of this data is basically just confusing me more than I already would be. lol
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Post by 90GTVert on May 8, 2024 13:49:39 GMT -5
I just took the first ride with the new kit. Tried to be nice and break it in a bit. I rode to a town, around town and back to wind up at 31 miles. It felt soft, and it did with the PWK too. The carb tune is off at least a little in spots, but since both do it I'm assuming it's largely from much less aggressive ignition timing than I've been used to at lower revs, a massive flywheel weight and/or CVT tune. Luckily we've got that awesome spring tuning weather back. 87 today, 71 and rain tomorrow, 61 the next day. Nice and consistent.
I used an 8Ah M18 battery fresh off of the charger and the bike was on for about 1hr10min with the halo and tail light, water pump and turn/brake lights as needed. Volts stayed at 12.0 on the gauge and the built in checker on the battery said 3of4 bars. Voltage was 19.57. Didn't expect it to be quite that high on an 18V batt. Checked another 8Ah just off the charger at 20.33V.
I'm not sure if it cools quite as well with the pump at 12V compared to usually 13-15V when moving with the MVT.... but it's not far off. At 86-87F the coolant never got much above 140F and would cool to the upper 120s at low load and moving. Most of the time I wasn't cruising any faster than 40ish though so I wasn't pushing it.
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sinfull
Scoot Enthusiast
Posts: 361
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Post by sinfull on May 8, 2024 15:30:38 GMT -5
I gave up trying to measure precisely, in a clean room at x temperature on a Tuesday with the earth rotational axis is always different from my garage measurement station š
Too many variables to even worry about, 2nd shift finish grinder Larry is heavy handed but his parts always in spec according to the go no go bore gauge.
Anyway glad to hear that you got it back up and running and the 18 volt battery is working out
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Post by aeroxbud on May 9, 2024 3:01:36 GMT -5
So the new ignition is your wheelie control? I guess that bore was slightly over, so got the next size up piston. Not what you were expecting. š
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Post by 90GTVert on May 9, 2024 9:28:25 GMT -5
So the new ignition is your wheelie control? It wouldn't work off the line. Don't know that I'll be doing 25-30MPH power wheelies right now though. Mostly feels wrong and I'm not used to any delay in power. It's normally the most responsive thing I've ever been on. I guess that bore was slightly over, so got the next size up piston. Not what you were expecting. š My understanding is that as the manufacturing equipment wears or has looser tolerances, the bores can be off a bit and that's why you get AA or B... hopefully no worse... cylinder kits brand new.
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tysta
Scoot Member
Posts: 51
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Post by tysta on May 12, 2024 23:41:04 GMT -5
I missed the mark on the fit a bit this time. I was aiming for a 2 thousandths slip fit as John suggested. I wound up with ~0.003ā so it slides a little too easily. Good thing I found some 20mm rings the other day. You could give the shop that sells these a call and ask if they can get hold of other sizes? Good idea, but I already ordered 2 of those. Figured it probably wouldnāt matter if they were not totally enclosed within the bearing. I made a couple of .4ā spacers for the mounts because I was going to be too close to the wheel and tire otherwise. I got started on the tubing frame. Didnāt get very far. I donāt have a tubing notcher, so I stuck a hole saw in the drill press to make the curve for the mount easier. It does a rough job with the wobble in the setup, but matches well enough after some minor cleanup. Seemed easier to freehand it with a grinder for the rear cutā¦ especially after seeing how much the 2.25ā hole saw moved around. Prob gonna TIG this stuff so itās cleaner and I donāt get spatter all over the wheel and engine trying to tack it up. Also thinking I'll probably have to ditch the MHR exhaust bracket to make it work with the torsen. I looked for bushings like Malossi uses in their bracket for the silencer support. No luck really. Best I can find for a reasonable price is a 20mm OD, 20mm thick, 8mm ID bushing for scoot rear shocks. Those are quite hard usually, so I don't know if that would do the job for vibration damping. I know John also does his own home brew bushing setups with hose and tubing IIRC, but I'll have to look at the Peace Pipe again if I do it that way. I was hoping to have a fixed bushing so it all just bolted on like the MHR though. Getting ahead of myself. I haven't even got the torsen done enough to see how the exhaust may or may not work with it yet. In other news, I talked to ScooterTuning at the end of last week to ask about the C piston thatās been on order for over 2 months. They are gonna ship the rest of my order (ignition and some extra circlips and such) because thereās still no known date for the piston. I ordered a C from GForce Thursday. Emailed them today to check if it was actually in stock or they knew when they could get it and Gary Fallon called me shortly after the email. He checked Malossi directly while I was on the phone and both B and C pistons have no known date so he said they may not even make them for all he knows. He said heās never even heard of anyone using a C piston. Still makes me wonder how many actually measure. He had a BB in stock which sites donāt even list usually. Thatās halfway between B and C, so just 0.005mm smaller than I intended to get. Close enough. They sent that today. If I melt another, I might be in deep do do or going back to an A that never met spec since it was new if I donāt want to get a new kit altogether. I had a 245mm shock and a shorter riser in my cart to help get T2 lower, plus brake pads for the front of the TMAX. Went to order that and now that stuff is gone aside from the brake pads. Shopping elsewhere for a rear shock looks like it will cost me quite a bit more than my discounted price from ScooterTuning, so that kinda sucks. I can still get a riser in a color I don't want I think. Not sure if a shorter riser will do much. I was thinking it would lean me over the bars more to transfer weight even more to the front and make a slightly smaller hole in the air, likely at the expense of a little comfort Hi Bert i been away for a few but i see you having problems to get the piston. sorry to say but thats silly just because should be very easy to them to have them the piston they use is from a ktm sx 105 and you can get them up to d letter . you also can bring your cylinder back to stock size i do that type of work all the time
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tysta
Scoot Member
Posts: 51
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Post by tysta on May 13, 2024 0:49:03 GMT -5
I've been talking to a guy that is trying to make his vertical Jog the quickest known. He's been messaging me for a while looking for info here and there. He's already very low 9s with low 5 second 0-60s on a 77cc. Looks like nothing you'd think twice about if it pulled up beside you too. In conversation he mentioned a weather tool being the same he uses for the pro-stock car, which caught my attention. Turns out he and his father have a machine shop and have been into racing his whole life. They even took a chunk of aluminum and turned it into a head for the pro-stock car. I know, this sounds irrelevant... but I figured I'd take the opportunity to ask him a question last night and told him about the conrod. He said he wouldn't think that 0.01mm would be an issue and that I'd probably worry about it though since I know now (true). The biggest concern he'd have would be if it were damaged the conrod could break. This doesn't look damaged at all. Again, on appearance it looks like it's new to me. i know exactly who is that.... and its not 100% like that. I've been checking a few service manuals. Surprisingly, most don't say much at all about the conrod small end. The YZ125 manual for example just said to put the pin and bearing in and check for free play. Some literally say nothing. I did find this in a Vespa S 50 manual... Looks like their conrod is supposed to be 16.999-17.011 standard. So that's already more deviation than I have, but they don't mention out of round. They do say maximum allowable is 17.060mm. They're allowing basically 0.05mm of wear or change and I'm at roughly 0.01mm. Again, I don't trust the snap gauge method beyond there for accuracy. Not even totally sure I'm accurate there, but it's about 0.01mm out of round. The manufacturers, from the manuals I've scanned... which is not a ton... don't say anything about out of round.
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tysta
Scoot Member
Posts: 51
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Post by tysta on May 13, 2024 0:52:56 GMT -5
It didn't wanna start. Checked that before pulling it apart. The ring did feel a little stubborn, so I think that is likely the reason... paired with an ignition that won't make a spark in less than perfect conditions. The aluminum on the non-thrust sides... the pin axis... can be felt by finger. Not fingernail... finger. It seems odd to me that the worst is there. Normally is the thrust axis. That didn't seem to take a lot more damage. Not saying anymore is good, but it's not like the pin axis. I'm not sure if maybe the wear on the thrust axis from last time causes it to then dig into the opposite axis or if something else is going on. I don't think this top end is gonna go back on. It may clean up OK, but how much can I put it through? Plus, it's not like it's easy to get another piston for closer to spec fit... at least not at a reasonable price or delivery time. Now it get's questionable for me... So I'm paranoid about the conrod/bearing/pin fit. I thought maybe it was a little too snug. Actually thought this during assembly when the pin was initially a little tough to push through and then I pulled it and reinstalled it and convinced myself that it wasn't too tight because it wasn't as difficult the 2nd time. I saved the 2 pistons that I've used before, along with their pins and bearings. They feel about the same in the rod. Wear doesn't look alarmingly different on any of them to me. If I use one of the old pistons without smeared aluminum on it, I can push the pin through the rod and bearing with ease. OK. Well, then I decide to check the small end of the conrod anyway. AFAIK it's supposed to be 17mm. The bearing is 13x17x17.7. I get 17.00mm if I measure up and down as it sits... which I would be exhaust to intake or I guess side to side. If I measure the opposite axis, which would be up and down in the bore, then I get 16.99mm. My measurements could be wrong. I tried with a snap gauge many times and used the calipers and micrometer both and measured with the calipers directly and all seem to tell me it's those numbers. Could be that I'm wrong and it's 17 and 17.01? Not even trying to get any closer than that. What I'm certain of is that the rod ID is smaller where it would be going up and down in the bore. I can take the snap gauge and set it in one direction and then it either gets loose or tight in the opposite, depending which way I'm trying it. No doubt there's a difference. A couple of things seem off to me here...Why would it either get smaller on the axis where I'd think it takes the most force, or get larger on the one that doesn't? I don't know a lot about cranks and rods, so is this common or at least something that others see? I'm hoping they made the side that should wear smaller and it's normal... but I have to expect that it should be round and that's purely wishful thinking out of despair. Is this crank certainly junk? I'm sure the rod could be replaced, but if I do it the crank may be junk anyway. Tried it once long ago and it went very bad. Right now the only thing that I know is that this sounds bad with a capital dollar sign. Bert thats ignition. i almost bet if you set at zero she will start fine and no problems easy way is to create a map for example 14dregress all the way throw the rpm and then check it at 5k the diference its how much you need to adjust on the static advance. that cylinder can be repairded if you need help with that just message me
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Post by Lucass2T on May 14, 2024 4:07:09 GMT -5
I think he's called Brent...not Bert
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Post by 90GTVert on May 14, 2024 6:51:15 GMT -5
Yesterday was my first day trying 1/8 mile runs with the new top end, and it was another fun one. On the first outing, it ran OK with a little over 900 EGT at 50MPH to my test spot and felt good testing. Times were low 10s and high 9s and EGT was 1100-something at 60MPH during test runs. On the way back I was messing with the throttle. WOT or near just didn't feel quite right. I assumed it to be due to low EGT probably telling me the main jet was a little large since in the past (before the new ignition and all of the recent troubles) it did best with ~1200 EGT at 60 during test passes. I played with the throttle and found that it sounded like detonation and didn't run quite right somewhere high in the throttle (throttle was not properly marked at that point). I held it there for a sec and then went WOT and it shut off. By the time I coasted to a stop, I got off and refired it and it ran fine. Whew. It's kinda dumb to hold it where I think there may be knock, but I've got away with it for testing so much in the past that a couple of seconds to try to see if I was right didn't worry me that much. Apparently it should. I pulled the plug when I got home because I still wasn't 100% sure if I was hearing knock or if it was just running poorly due to jetting or some other issue. Looks like some peppering on the porcelain. It's dark down at the bottom, but I can't ever say that I can read a plug properly without cutting it and I don't have (and can't afford) 100 plugs. The top of the porcelain worried me a bit, aside from the specks. I used this plug for the break in ride and the test ride so I wasn't expecting to see it mostly white up in the low and mid throttle areas of the porcelain unless it was soaked, but it was and it was dry. I think what I'm seeing across the strap is cleaning, but I may be seeing aluminum. That made me think that I may just need a needle adjustment, so I lowered the needle clip from the leanest position by 1 spot and rode again. It didn't feel as soft as it had in some past rides, but still lagged on quick WOT a little. Test runs were a little better. I tried to avoid the problem areas for the most part. I don't really use 1/2 to 3/4 throttle on this thing anyway. I can take off pretty quick (for a small scoot) at 1/4 throttle and that will maintain 50MPH or more usually so I'm largely down in that range or up at WOT for runs or fooling around. Not ideal tuning methodology, but at this point I'm hoping I can get it going hard and keep it in one piece for Ocean City and TN. OC is this weekend. TN is only I think 3 weeks before I'd be leaving. I moved down from a 150 main jet to a 145 to see how much that changed EGT at WOT and 1/8 mile passes. That could be the death of the kit again if EGTs are just low because timing is changing where the heat is, but with it feeling off at WOT I have to try. I got 0.6 miles down the road at about 40MPH and it suddenly felt like I was braking just before it revved to 15,000RPM. I knew instantly that the belt was gone. Ahh. Just what I wanted, to take a walk home with the scoot. I swear my neighbors and local traffic must think this thing gets pushed or put in a truck more than it runs anymore... and they may be right. The belt just broke and didn't go totally to pieces like many fails that I've had. It did manage to take out more fins on the front fixed half. I hadn't thought much about the belt recently while trying to get through all of the big carb and ignition related crap. It was down to ~18.8mm, which isn't all that much wear since it's supposed to be 19.5mm new but the one's I've had range from 19.5 to 19.2mm fresh out of the box. I was surprised to see that I've been using that belt for 1,662 miles though. I'm certainly not going to complain about that after years of 100-250 mile belt failures on the Minarelli clone. It's gotta either be that I modified the MHR torque driver on the clone and/or to some degree better alignment with the RC-One. Luckily most of the CVT was fine with cleaning, and I regreased the variator. The grease in the TD looked good so I didn't bother. I had a new fixed half on hand because it was getting worn anyway. The vari and the used fixed half both had markings that I could feel near their centers. They were actually there the last time I had it apart too, when I was messing with shimming. I'm wondering if there could have been too much pressure on the belt from lack of shimming and it managed to fudge up the surfaces near center. I've always figured the belt just wouldn't go down far enough to harm anything and would simply ride a little higher, but maybe it can get squeezed in there more than I thought. I stuck the vari in the lathe and hand filed (gently just to smooth the small area near center) and lightly sanded the whole face. Feels good now and I don't think I changed much. Of course tiny differences can make or break a CVT sometimes, so I guess we'll see. I got the whole thing together with a new belt and took a 28 mile easy break in ride for the belt's benefit. No time to do testing after that and I wanted to let the belt cool anyway. I'm thinking about changing timing before I try any test runs today. I started out with the idea of just straightening the curve between 10k and 14k because that will be less advance in that area to maybe lessen chances of more failures a little and I don't think I really need all of that timing there. Then I figured I might as well drop most of the curve a degree since it seemed to still be about a degree more advanced than intended at low revs. I put a dot in at 13.5kRPM at 15 degrees. Not sure that it really matches up there like it appears, or if it's the timing light and I've never done the straight curve to test that I talked about, but it should be within a degree of where I think I'd want it anyway. It's yet another change all at once, but with the 145 main jet and a new belt, I'm already not going to be certain on first passes what changed what... so I think I might as well make it slightly safer while I'm at it. The forecast says it's probably going to rain part of today and tomorrow so I don't have a whole lot of time to mess with it before the weekend and as of now the weekend may even be at least partially rained out.
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Post by Lucass2T on May 14, 2024 7:18:01 GMT -5
And you're not even swapping around pipes, tires, shocks or compression ratio's. Can you imagine how much work road racing teams had back in the days during a race weekend getting a bike dialed in
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tysta
Scoot Member
Posts: 51
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Post by tysta on May 14, 2024 10:05:54 GMT -5
I think he's called Brent...not Bert lol may bad , iam bad with names
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sinfull
Scoot Enthusiast
Posts: 361
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Post by sinfull on May 16, 2024 2:42:55 GMT -5
Always hate timing, hardest part is getting my head to think trigger 1st,
Trigger event has to happen 1st, system can't guess when to fire, so trigger gets advance and then holds spark till spark event so it drives my brain crazy, trigger gets advance and system delays for advance, retard is trigger and then more delay by the system. Hurts my head to comprehend that advance is actually less retard and retard is just more retard depending on the iggy.
I actually prefer the fixed gy6 ignition with the trigger that you can't adjust because it is cast into the flywheel, so much less thinking.
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