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Post by kliff on Nov 8, 2009 11:47:29 GMT -5
it is hard to tell by the photos you actually are not doing anything with the port timing what you are doing is making where the pipe mounts to the bore as big as the gasket if you are familiar with gasket matching then you know what i'm talking about and once you get the outer edge matched to the size of the gasket then you blend it back into the port i would have to say about 1/2 way (you have to feel where the glob ends) ill see if i can make a drawing i'm not good with that kind of stuff There is so much that can be found in most OEM 2 stroke ports, just like he 4 strokers, without changing the port timing on the 2T or cam on the 4t. Openning, smoothing, and strightenning the exhaust for a good straight shot of exhaust gas to the header, is a no brainer. Much, much more work, requiring a full teardown, but port matching the ports in the cylinder to the case, and again, no timing changes or window enlarging......yeah buddy. At least back in the day of DT1's, Montessa's, Bultacos..... back in the day when you carried one or 2 spare head gaskets..... cause when ya was blastin' through the dessert on a multi day camp trip, with a paper map and compass, we'd invariably end up in Mexico.... add one or 2 head gaskets, lower the compression, fill up with whatever they had, and carry on....run out of oil....hit the pharmacy..all the small towns had 'em, and by a quart of Castor oil... for about $0.25....gas, for $0.22/gal. Everything was cheap down there! EVERYTHING! Yeah those were the days. Wish I'd been able to get out west and do it more.
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Post by blackbomber on Nov 8, 2009 15:55:36 GMT -5
Well then, I'd say the challenge is on. I wanted to put JMKJR22's derestriction into play today, but the temp has been an unseasonable 60 F, so I didn't want to tear into it. I think I'll head out now and get started.
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Post by blackbomber on Nov 9, 2009 7:30:07 GMT -5
I pulled my top end last night, and smoothed out the exhaust port. All I can say is WOW. I was not very daring, and probably did not increase much. I did match it to the pipe, and smooth out the casting as deep as I could get. If I had a smaller tool, I could get deeper, but the collet chuck on my die grinder only allowed me so far in with the stone I was using. Nevertheless, I'm very impressed with the result. I only had time to take a quick run down my road (shame on me for even attempting a top speed run in the neigborhood) and didn't even warm it up properly (even more shame). Curiously, my indicated top speed was not increased whatsoever. But the throttle response, and torque were noticably improved. While I don't have a baseline for acceleration, it feels to accelerate better up to an indicated 40mph (that's like 28mph). I don't think I have a limiter in my ignition, since I don't feel it, and have gotten an indicated 50mph on a long downhil run before (probably an actual 40mph or so, my speedo is WAY off). Anyhow, it was well worth the effort. Plus now I know I have a 10mm wristpin for when I order the BBK. Attachments:
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Post by blackbomber on Nov 9, 2009 9:46:14 GMT -5
Just after my last post, I took my scoot on a 8 mile (round) trip to get coffee with a friend. I did warm it up properly, and I had enough room to prove that I honestly didn't gain any top speed. Furthermore, the hill pulling power didn't seem to improve (above 25mph, anyway). Still, it feels great. My friend rode it, and also noticed the improvement.
One thing I realized is that my exhaust gasket is leaking ever so slightly. I guess I reused it one too many times. I'll change it out today, and see if it nets any improvement.
A second thing I realized is that for several seconds after a cold start, it idles high, then dies down to normal. When I noticed this last night, I thought it might be related to the assembly lube or something. I know that doesn't make sense, but when it started running normal, I didn't know what else to think. Could this be related to the exhaust leak? I guess I'll find out in time.
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jmkjr72
contributing staff
Commander 132nd Northern Cav. Division
Posts: 2,779
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Post by jmkjr72 on Nov 9, 2009 19:16:39 GMT -5
to get full efect out of the fix if you have a snorkel or some sort of reducer on the inlet of your airbox remove it and either upjet or raise the needle in the carb have you looked at the varaitor for a "wedding band" in the varaitor i hope you also double checked the pipe itself for a restricting washer in the end of the pipe (some times its in the gasket) i would swap that gasket out right away or even try some exhaust putty to seal it up for now i would say wow your speedo is off by a ton my zumas was only off by 2 to4 mph till i put the taller tires on you may need to tune your rollers too maybe a bit heavier it would depeend upon what you got in there already
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Post by blackbomber on Nov 10, 2009 8:46:45 GMT -5
This is the airbox I have. As you can see, not only is there a tiny snorkel, but a silencer tube. I'm running it as is, although I plan to add a larger or second inlet in conjunction with any mixture adjustment, when that time comes. I think I'll hold off on touching that until I install a 70cc top end. Have not had the belt cover off at all. I wanted to do that yesterday (also to measure / weigh my rollers). I ran out of time. Depending on how my workload is today, maybe I'll check that tonight. No other restriction in exhaust. I put a Viton O-Ring in place of the smashed metal / fiber ring. It sealed fine on my "lift" (18" tall wood platform with 2"x8" ramp). Again, time prevented any test run. Yeah, the speedo is way off. The bike does have the correct size tires. Another thing that was WAY off was the tire pressure (dangerously low). Obviously that would limit top speed. I'm also wondering if that could be throwing off the speedo (given that the axle is likely riding closer to the ground, giving the effect of a smaller diameter tire (thus spinning the wheel faster). I doubt it would make that much difference, but a test against the GPS will show. Again, ran out of time. As for the rollers / variator, my understanding is that I should measure how high the belt rides on the front pulley. When I have the cover off, I'll mark it, and check. Thanks for the continued help and advice. Attachments:
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Post by blackbomber on Nov 10, 2009 19:43:05 GMT -5
Update: I didn't have time to do anything but a test run. My speed was exactly the same as before according to the speedometer. The difference is that according to GPS, my top speed raised from 33mph to 41mph. And GPS and the speedo are spot on up to about 30mph, when the speedo starts getting optimistic. Still, this is much better than before. The tire pressure is what made the difference in both speed and speedo error. Interestingly, the ride is not so much harsher than before. It was extremely harsh, and now it's really extremely harsh. I guess that must be the bane of 10" tires on frost heaved New England roads.
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jmkjr72
contributing staff
Commander 132nd Northern Cav. Division
Posts: 2,779
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Post by jmkjr72 on Nov 10, 2009 19:58:24 GMT -5
low tires will do it every time your roads cant be no worse then the roads here in ne wi where abouts in cn are you my dad was stationed at groton for a while years ago
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Post by blackbomber on Nov 11, 2009 18:17:10 GMT -5
I have no doubt that the farther north one goes, the worse the pavement is for a given age. I live in Wolcott, CT, which is central CT, but have been to Groton. I sold my '67 Dart to the wife of a sailor stationed there, in fact. They bought it to use daily, I used it daily (12 months out of the year) as did the owner before me, a Triumph cycle fan. I'm ashamed to have let something as elementary as tire pressure go unnoticed for so long. In my defense, I was in the middle of a major garage reorganization, and couldn't put my hands on my one good pencil gauge when I first got the bike. After I got it running and rode it, I guess I forgot. Anyway, I NEED to do something about that ride, or I'm going to chip some teeth or something. My GPS unit popped off the mount, and went bouncing down the road. Still works, though. jmkr72, not sure of the Canadian parts source you mentioned, but today I just found SPmotostore.com. Found them through their eBay auctions, remarkably. Anyway, they are the first place I have found that sells Top Performance, and from their description, it's definately in my top four (probably two). I have finally decided on an upgrade path, so choosing a big bore should be easier now. My originally was to spend $400 or under on a bike that I wouldn't need to register. I got the Milano for $250, and have spent another $50, but I don't even really need to count that, since it was consumables (battery, two stroke oil, light bulbs). To stay with my needs and my price, I think a 70cc top end, CF or fiberglass reeds (for reliability) and a rejet with the stock carb and pipe is my best choice for now. I strongly wish to keep the sound level in check (plus the stock look is a plus), so this path seems right from all angles. And with the prices I'm seeing on good quality stuff from SPmoto, I can make this a reality. I like the idea of a two ring cast iron cylinder. Their Mallosi, Pollini, and Top Performance all fit the bill. The Mallosi includes reeds, so that makes the initially higher price competitive. I'm also looking at the Stage 6 (Athena) kit they have, but I have mixed feelings about a plated alloy bore (I'm a classic Guzzi owner). I do a lot of short trips around the block, and am notoriously bad about propper warm ups. I know an alloy bore will warm up faster than an iron, but also distorts more during that time. And Guzzi has taught me the evils of failed Nickasil. What are the thoughts on these choices with a stock pipe and carb? I can always add a pipe can carb later if I change my mind, but for now I'm decided. Plus I hate the idea of having to increase the stall speed of my clutch just to take off with a pipe that has a peaky powerband. I like the way this bike takes off and accellerates now when I'm not in traffic. I just want better power up hills, and a higher top speed so as not to be a nusiance in traffic. Constructive critisizm welcome. As I posted earlier, I formerly owned an Aprilia RS50 with $1300.00 worth of Italian go fast goodies, so while FAR from the expert, I do have a little experiance with modded 2T's.
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jmkjr72
contributing staff
Commander 132nd Northern Cav. Division
Posts: 2,779
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Post by jmkjr72 on Nov 11, 2009 21:18:56 GMT -5
sp motors was one of the places i like infact thats who i got my trophy kit from(go to there web site not there ebay store i think you can get better deals at there web site just look up the zuma 02 to 08) im not a big fan of the athena single ring kit a few guys have had some issues with them and like you know you skuff the coating and your done you cant hone it or anything
the pipe i am running the leo vince sp3 pn 4421 (for mulgati) has been a great stock style pipe i would say its more throaty then the stock yamaha pipe with a cat in it the trophy will give you more top end then either of the other kits and the polin(there are 2 the sport a torque monster not top end just a bit better then stock and can be run with a stock carb and the corsa (this is the one im using in my lc build there is an ac version) but you need a bigger carb with this kit even though it is cast iron 2 ring its like a mid race kit) the malosi is a good kit to dont forget the stage 6 street race(even though it says street race this is a cast iron 2 ring kit)
i know from personal experiance that the trophy works well with a stock or stock style pipe and an upjetted carb and you can upgrade to a pipe or bigger carb later
as for the suspension i have no idea you have a retro style with skiny tires right the funny thing is my stella with the skiny tires has a smoother ride then my zuma with the bigger tires
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Post by blackbomber on Nov 12, 2009 8:14:56 GMT -5
Thanks for the detailed reply. I should have mentioned that (with the exception of the Stage 6 which is the one I found on eBay and brought me to the site) I was comparing entry level sport kits in the same price range. The TP Trophy really sounds like it's right up my alley. I'm not looking to show anyone up, but I want a higher cruising speed in traffic. I'm not strictly in a hurry, but the riding season here is not getting any better, so I might just go for the Trophy, variator and jet kit for now, and see where that gets me. Oh, and the temptation of thinking the Mallosi kit would be cheaper because it comes with reed petals was pure naivety on my part. I see SP sells Athena CF reeds to fit in the standard cage (I think) for less than $13.00. I'm assuming there is no compelling reason to go to an aftermarket cage with the level of tune I'm looking for. I just want to get the metal ones out of there, and I'm guessing the CF will give better high rpm performance even in a stock cage. Correct me if I'm misunderstanding this.
I took a look at the SP3 (the few retailers I looked at were all pushing the ZX style race look pipes). Besides the obvious attractive price and a look that compliments my style bike better, I see it seems to have a bit of an expansion design. Looks like it will work much better than the Ruima one. I don't have a cat, so I may wind up not too far off from where my bike sounds now.
As for my suspension, I think either I'm getting old, or I have a really crappy bike. If I fix every shortcoming so it matches a Vino, I could have just bought a Vino. Actually, I passed on a very well cared for 2007 or 2008 Vino 125. It was my dad's and he asked me if I wanted to buy it before putting it on consignment at the dealer. I turned it down because I thought it was out of my price range. Of course I wanted a 49cc 2t, but when I found out he let it go for $1000, I was shocked. I think the dealer must have pulled a fast one, because that is just an insult. Oh well. At least if this scooter phase of mine sticks, and I don't go for a bigger one in the future, I can find a quality used Minarelli horiz. based scooter, and transfer the parts over. Now I'm thinking too far aheah. Thanks again for all the advice. It's really helping me to make a decision I feel confidence in.
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Post by Rebel on Nov 12, 2009 13:54:33 GMT -5
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Post by blackbomber on Nov 12, 2009 13:59:08 GMT -5
Thanks, Rebel. I've gone through every one of those posts. The carb info, CVT assembly, and homemade reed spacer were of particular interest to me.
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Post by Rebel on Nov 12, 2009 14:01:53 GMT -5
I might have added the second thread after you read that, but I'm assuming also that you may have combed through everything now, I just didn't want you to miss something that might help you out.
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Post by blackbomber on Nov 12, 2009 14:44:43 GMT -5
No, actually I replied in haste. I read all of the how to's, but not the buildup on that Vento (although I had already seen some of that work in other posts). Pretty cool what some are doing.
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