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Post by Kasperthelost on Nov 24, 2016 15:15:28 GMT -5
And I am positive the cam is lined up correctly the small hole are in line and the big hole is facing forward
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Post by Kasperthelost on Nov 24, 2016 15:16:02 GMT -5
I will take a picture of the cam so you can see it
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Post by Kasperthelost on Nov 24, 2016 15:17:26 GMT -5
And yes I have watched Brents videos quite a few times.I mean I'm obviously overlooking something or have faulty parts somewhere.
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Post by humanshield on Nov 24, 2016 16:20:54 GMT -5
Runs good at low rpms - stutters badly when you open the throttle. It "sounds" like a carburetor issue...as if it's not getting enough fuel through the main jet. There are a number of things that can cause this.
Carburetor - You jetted it to 90MJ and that should be close. Try the original carb again for the fun of it. Try raising the needle all the way to the top. Check the Main Jet again to Make SURE it is clear. Look through it. Fuel - Bad fuel will cause funky problems. Is the fuel flowing to the carb ok?
Airbox - See how it runs with nothing attached on the air filter side (to rule out weird problems with air box)
Timing - This doesn't really sound like a timing issue to me.
Compression - Anything above about 70 will "work", but best around 175 - 185 ish
Cylinder head - Check for cracks, broken springs (causing valve float) and leaking valves
Ignition System - Test Stator output. Try a different spark plug. Try a different Coil. Check for proper grounding Try a different spark plug cable (or test the resistance)
Vacuum System - Air leaks can cause all kinds of weird problems. Make sure there are none.
Intake Manifold - If there is a crack in the rubber, it can cause stuttering as the vacuum increases and air gets sucked in
Exhaust - A blocked exhaust can restrict flow and cause a loss of power...but usually not stuttering
still thinking....I wish I was close by....this would be fun (but probably a simple oversight)
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Post by Kasperthelost on Nov 24, 2016 16:23:06 GMT -5
OK so I was checking parts out for flaws and I came across one only one part that is not right and it's the rocker arms the exhaust side it's kind of hard to move like it sticks and you have to push on it a lIL bit not alot but way more than the other side which moves freely like um guessing that it should could this be the root of my problem? Please tell me it is. Hope to hear from you guys soon thanks again for the help I hope one day to be knowledgeable enough to help someone out.
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Post by humanshield on Nov 24, 2016 16:55:12 GMT -5
Sounds like a definite possibility.
This is with the rocker arm removed from the motor??
Because if this is ON the motor, you may have a broken valve spring. Each valve has two as you might know.
If a spring is broken, valve float could cause the stutter.
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Post by Kasperthelost on Nov 25, 2016 1:02:10 GMT -5
Yes that is with the rocker assembly taken off I was going to try the stock cam shaft and when I removed the rocker assembly I noticed the exhaust rocker had trouble moving unlike the intake side which moves like it should. The valve springs are still good as new. The exhaust rocker still moves it was just with difficulty I'm thinking that's the problem. Considering it is the first thing so far that has actually been wrong with the install. I feel like I'm getting somewhere I guess we will see when the new rocker assembly comes in a few days I pray this is the issue and I don't have anymore for sometime. Could one use a 47mm BVH on a 50mm bbk? Is there a huge difference in the heads?
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Post by humanshield on Nov 25, 2016 15:41:50 GMT -5
The rocker arms should move completely freely. It's a bit suspicious that one was hard to move. The cam would force it open, but the spring might have trouble fully closing it...and yes, if that were the case it could stutter.
It depends on how much force we're talking. Let's hope that's it.
The heads all have the same bolt pattern and it will fit. The issue is piston clearance and most importantly compression ration. The 47mm head will have a smaller volume than the 50mm head.
If the compression is between 160 and 190 (+/-) and the valves clear, you'll be ok
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Post by Kasperthelost on Nov 25, 2016 17:39:54 GMT -5
I think that's why it idled perfect but when I gave it gas the fact that it was harder to move slowed it down a bit making it struggle causing the stutter. I asked about the head because I found out the one I have is a 47mm big valve head and I thought it was a 50mm I ordered the 50mm bbk thinking the BVH was the same turns out the head actually is a 47mm the valves clear for sure and it has decent compression from testing only with my finger I know not accurate at all but it pops my finger off the hole so there is compression. My question is could the combo of a bad exhaust rocker arm and the wrong head cause the issues? IMO the head seems fine but the rocker is clearly faulty and causing my issues. But I think I'm just going to get the right head I don't need anymore problems and the correct size head is not very expensive the one good thing about the scooters is parts are affordable and pretty much at arms length and plentiful. Thanks again for offering me some scooter wisdom I haven't ordered the new head and rocker yet but when they come in I'll let everyone know
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Post by Kasperthelost on Dec 6, 2016 14:58:46 GMT -5
Ok I'm finally back sorry about it taking so long for me to put something up on here I have been waiting for parts to come which they did last week finally but the parts were defective so I had to complain and get new ones sent and then wait all over again for them to come in... Well now they are here and I just spent the past couple hours installing them. So now I have the whole 50mm bbk installed with BVH and a9 cam and a 20mm carb with a 100 main jet and I forget the idle jet 38 maybe anyway it's all installed and it's no longer stuttering like in the previous video but now there's some smoke now since completing the install I have only had it running a total of maybe five minutes so I was obviously thinking the light oil I used as assembly lube is just burning off but after five minutes I would think it would be gone after that I don't know. I guess I'm wondering is this normal? Because now I'm scared something else is messed up and I don't want to run it to see if it burns off if it's actually burning something else say my piston rings I heard they put off white smoke and this is kinda white smoke. I don't know if any of you have any ideas please let me know.
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Post by Kasperthelost on Dec 6, 2016 15:07:04 GMT -5
Also it starts right up with Es or Kickstarter pretty quick too best in awhile I also checked my belt and cleaned up the variatior and replaced the weights they were stock ones with close to 6000 miles on them I'm not sure how much stock weights are but these were wore down to 5 grams so it's my guess they were pretty worn off I will say my bike gradually got faster but was losing top speed but took off good. So I replaced them with 7 gram rollers I heard these are a good starting weight. I'll either go up or down or stay the same if I like there performance. I also got a new contra spring and clutch springs 1000rpm for both and the same I may try higher or lower or stay the same. But first thing I want to do is deal with the smoke issue I know it's not supposed to smoke so there's obviously some sort of issue I am thinking maybe the ring gaps may have somehow turned when I installed the head making it so there could be oil getting into the combustion chamber causing smoke.
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Post by Cincikid on Dec 6, 2016 18:37:41 GMT -5
Progress! You're doing the right thing, waiting for replies before running the engine. IDK, But someone will and will post shortly.
With the roller weights, In my experience 7 would be a little heavy but may turn out to be just what you need. If 7 is heavy you could order say 5,s and place them 5,7,5,7 and so on. You would then have 6,s. So you would then have 5,6 or7 gram weights. Also upping the contra spring to a 15000 would have the same effect as going lighter in roller weight and should give you more RPMs uphill. I like to tune more toward top speed and find 15000 clutch spring help me get off the line and into powerband much better than the 1000's but again depends on your preference and set up.
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Post by Kasperthelost on Dec 6, 2016 20:18:14 GMT -5
Thanks yeah the weights and spring are relatively cheap so I figure I'll try these first and go from there I think sixes might be what I want because the old ones were five from being worn and I noticed top speed loss but I'll try seven and see what happens and also try the 1000rom springs and go from there well... As soon as I get some help I wish one of you guys was my neighbor. Please help me out people you're my only hope.
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Post by 90GTVert on Dec 7, 2016 15:04:30 GMT -5
White smoke is usually burning oil. Could be a piston ring issue, like bad rings or perhaps a gaps ended up aligned instead of staggered, or maybe bad valve stem seals. Smoking from low quality piston rings seems to be a pretty common issue with Chinese BBKs. Some replace them with Taiwan made rings from NCY, Naraku, Hoca, Taida, etc... Assembly oil should burn off pretty quickly. You can try to give it a few more minutes to see if it quits or take it apart to look at the end gaps and how they are aligned.
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Post by Kasperthelost on Dec 8, 2016 10:22:49 GMT -5
Ugh! That's basically what I was thinking and hoping I wouldn't have to do but aparently I have to so I'll be back.thanks AGAIN.
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