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Post by endru on Jun 10, 2013 21:35:07 GMT -5
Okay here's the update. I first pulled the plug and yup it was running rich. That was a good call skuttadawg. Downjetted to a #  and I saw a lot of improvement. It was still popping and hesitating, but it would pick up more speed than before. Suspecting an exhaust leak, I put on the stock muffler. It dampened a lot of the popping sound but it was still hesitating and higher rpm's. With the stock exhaust, I could hear some popping coming out of the air intake. Put in 8.5 gram rollers from my kit. It put me well below my power band, but at least now I was hitting 30, though it was still taking me as much time as before to get to that point. The nice part about that was that I could really isolate when the problems were happening. Low rpms are great, right up until just after the clutch engages. After that the engine starts feeling sick, and then if I briefly crank full throttle it sounds and feels really unhappy. I'm stunned because I messed around with all kinds of jet sizes and all kinds of weights and it never caused me these kinds of performance issues. I guess it could still be to rich... but jeez I was running an #80 with my stock kit no problem. I'm still suspecting an exhaust leak, so my next step is to get a new gasket ordered and try that out. Now for the happy side of the story. I was finally able to get my new gears pressed. I had trouble finding a machine shop that would do it. The first guy took a look at them and saw how tight the fit was and just said "there's no way that'll work, I'm going to decline." No amount of convincing would get him to even attempt it. The next machine shop the guy wanted to charge me $25 to have it done. When I balked and said it was a 10 minute job max, he literally shoved them back at me and said "see you later then." I asked him what his hourly rate was and he said $50... guess math wasn't his strong point. I was pretty hopeless by that point. I went to the last place and the guy was super friendly. He took me back with him and he had me help him position it under the press. It went right in like butter, It was 6 minutes from the time he punched in until the time he punched out. And then to make things even better, he decided to not even charge me.  I was ecstatic. ;D |
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Post by endru on Jun 9, 2013 20:37:19 GMT -5
[replyingto=lykos23]lykos23[/replyingto]Can't wait! That used to by my straight downhill, wind at my back, head tucked top speed. Hopefully that and even better then with the gears and an a9 cam.
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Post by endru on Jun 9, 2013 20:22:50 GMT -5
Hey thanks everybody! Tomorrow night I'll change the weights using my roller kit. I knew I would need a weight change after installing the bbk, I was just hoping to get everything working properly before then. I don't really think the weights are the problem though. I'm only revving until maybe 3.5k rpm at most before it sputters. With these weights and springs I should at least be getting 25 mph before over revving becomes an issue... I'm barely hitting 10 mph and it's hesitating, sputtering and skipping. skuttadawg - So the carb I have is stock, which I'm guessing is 17mm but I'll need to measure tomorrow to make sure. Do smaller carbs in general require smaller jets for the same displacement engine application? My thinking is that a smaller carb won't move as much air, so it would require smaller jets to keep from running rich. I'm really encouraged by your example with using jets that were too large. Would yours sputter and not gain speed, or just sputter while at the speed you wanted? My next smallest jet is an # . I'd prefer to try an #  first, but if the # seems to solve the problem then I'll buy an # and do the plug chop. An exhaust leak is possible, I'll order a new gasket just in case, as well as a #38 pilot jet. @lykos - I'm glad you chimed in, I fee like we're in the same boat in a lot of ways. You were on the old skuttadawg site too, right? So what size carb are you using with your  main jet? Thanks again, I'll update again after I make these changes. Can't wait to go riding and do the "real" break-in. |
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Post by endru on Jun 8, 2013 22:00:56 GMT -5
So this weekend I installed my 83cc BBK from scrappy's. It was a great feeling to get it all put together and have the scoot start right up  Absolutely no problems from the starter, which I've heard can be difficult with the BBK's. But... after letting it idle a good 20 minutes to warm up and let the rings initially seat, I went to take it for a test run and found that it won't accelerate. It revs up enough to engage the clutch and then wants to go, but suddenly bogs, sputters and hesitates but stays running. My idle in fact is really steady, although adjusting the A/F screw and even the idle screw don't have much of an effect on the idle like they did when it was stock. I've done my own troubleshooting all day and haven't solved it yet. I adjusted from my initial #  jet down to a #92 and # , all of which didn't have a significant effect. Then I was sure the timing chain must have been off one link, but when the flywheel T lines up with the crankcase tab, the two smaller holes on the cam are perfectly parallel to the head and the large whole is perpendicular like they should be. Sprayed carb cleaner around the intake and exhaust while it was running to check for leaks, nothing noted. I would check compression if I had a gauge, but I'm willing to go out and get one if all else fails. What else could it be? Here are all the other relevant (and maybe some irrelevant) details: It's a Puma Amor, Uni-style filter, performance exhaust, valves at .004" and .005", stock carb, #35 idle, stock head, stock CDI, orange coil, 5 gram sliders, 1500 rpm clutch springs and contra spring, iridium plug... I think I got it all ;D Thanks everybody in advance! |
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Post by endru on Jun 7, 2013 21:50:09 GMT -5
Thanks millsc. Shouldn't be too hard to find a machine shop around here, I'm just hoping they don't charge too much.
It's no wonder it requires a giant press... you look at the whole in the big gear that the little one is supposed to fit inside and it seems like there's no way the two could fit together. We'll see!
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Post by endru on Jun 6, 2013 15:32:57 GMT -5
[replyingto=awhitlock]endru[/replyingto]Just went to the mechanic near my house to have them press the new gears together with their hydraulic press. But... it didn't work, they couldn't get them to go together! What the heck?!  I guess I'll just go try at some other shops in town to see if they can do it. Any other suggestions? |
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Post by endru on Jun 3, 2013 21:33:57 GMT -5
You might try going to autozone or someplace similar to "borrow" the compression tester. I know they have a ton of tools you can buy and then return when you're done for a full refund, I'm not sure if a compression tester is one of them. It would hopefully come with various adapters. If you do end up needing another base gasket for the head, let me know where you get it from. I'm just a couple days behind you in starting my BBK install, and I may need one too. There's always a chance that your battery and starter will be just strong enough after installation. Good luck! |
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Post by endru on May 29, 2013 21:14:39 GMT -5
Well in that case, here's a video I found with a quick youtube search. I guess the key is not scratching the side of the piston and avoiding excessive stretching of the ring and possibly breaking it.
How to install piston rings by hand:
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Post by endru on May 29, 2013 19:19:14 GMT -5
[replyingto=lykos23]lykos23[/replyingto]I saw the the piston ring installer on your list of things to buy. My first BBK install is pending, and I'm just wondering how many of you use a tool to install the rings and how many just do it carefully by hand. Lykos, depending on the feedback, maybe that's an item you could cut out and save a few bucks. BTW have you considered jet sizes higher than yet? I think might be just fine, but going a little richer might be easier on your bearings. I'm not speaking from experience, just what I've heard from others on the forum. |
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Post by endru on May 27, 2013 9:35:34 GMT -5
So sounds like stock I had 69mm valves and now this new head is 64mm valves, cause when I just visually look at them from the side the stock head has the valve springs sticking out of it a lot more than the new head. Does this sound like 64 vs 69 valve problem? My guess is yes. I wish I could say definitively, but I haven't had the hands on experience with two different size heads yet. I just researched like crazy for whenever I am ready to buy a new head. I'm sure millsc will chime in with his opinion. He's had a lot more experience than me, he knows what he's talking about. From what I've heard, you may be able to just swap out the rocker arms to solve the problem. |
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Post by endru on May 27, 2013 7:48:29 GMT -5
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Post by endru on May 26, 2013 22:21:33 GMT -5
[replyingto=millsc]millsc[/replyingto]I had my brother over at the time showing him how the transmission works and I had him count the teeth. After his first count I said that's impossible, count them again. He got the same count second time... we were low on time then so I had to quick get them back in and didn't count them myself. That being said, whatever the stock gears were, I'm still going with a 16/50 upgrade. Just as long as there's no chance the new gears wouldn't "fit".
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Post by endru on May 26, 2013 22:03:14 GMT -5
Hank - man I wish I had a b&m shop around here that sold supplies and parts. The place in town where I bought my scoot, the guy doesn't sell anything besides the scoots and won't install any performance upgrades, just does basic repairs. At least that's what he said when I bought it a year ago. But that's okay, I really prefer doing it all myself, I have learned so much since I started and half the fun of riding is doing the work on it yourself. It's just a pain when I need an exhaust gasket or something little and I have to pay shipping and wait a week for it  Millsc - that's the set I found too. Gotta love Scrappys, especially their ebay store! |
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Post by endru on May 25, 2013 20:52:24 GMT -5
[replyingto=alleyoop]alleyoop[/replyingto]Thanks for the quick reply Alleyoop.
What's the likelyhood that they wouldn't fit? I've never heard of anyone having that problem before, but I haven't been in the scooter scene all that long. I guess I should have measured the diameter of my gears while I was in there, it never crossed my mind that a new set of gears might not fit.
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Post by endru on May 25, 2013 20:37:10 GMT -5
Since I'm installing my 50mm bbk soon, I decided on complementing the kit with some taller final drive gears. I assumed that buying a set of 16/50 gears would be a nice 1 up 1 down adjustment, assuming that my stock gears were 15/51 like most. Just to be on the safe I opened up the gear housing to check and wow... they're 14/53. So what does this mean for my new gearing? I can still go with 16/50 gears, right? The process of pulling out the gears was interesting too. I thought everything could be accessed inside of the CVT cover, I remember seeing videos on YouTube like that. But apparently the gear housing comes off the backside of the CVT while still connected to the wheel. Because the wheel was connected to the gearbox, I had to remove the exhaust in order to pull it off far enough. And then the rear brake cable was still connected to it...  |
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and I saw a lot of improvement. It was still popping and hesitating, but it would pick up more speed than before. Suspecting an exhaust leak, I put on the stock muffler. It dampened a lot of the popping sound but it was still hesitating and higher rpm's. With the stock exhaust, I could hear some popping coming out of the air intake. Put in 8.5 gram rollers from my kit. It put me well below my power band, but at least now I was hitting 30, though it was still taking me as much time as before to get to that point. The nice part about that was that I could really isolate when the problems were happening. Low rpms are great, right up until just after the clutch engages. After that the engine starts feeling sick, and then if I briefly crank full throttle it sounds and feels really unhappy. I'm stunned because I messed around with all kinds of jet sizes and all kinds of weights and it never caused me these kinds of performance issues. I guess it could still be to rich... but jeez I was running an #80 with my stock kit no problem. I'm still suspecting an exhaust leak, so my next step is to get a new gasket ordered and try that out. 
first, but if the #
main jet? 
jet down to a #92 and #