|
Post by Kasperthelost on Nov 14, 2016 7:15:38 GMT -5
My install went great in my opinion no problems after the install I got it started I let it idle for a few minutes all seemed well until I tried to rev it up it won't rev over about a quarter throttle up to there it will even move slowly but won't rev over that it sputters doesn't stall just bogs down I tried everything I could think of changing jets checking hoses right now it's not running due to wrong jet sizes I think. But even when I had it running it wouldn't go it has compression spark and gas so I'm unsure what to do this is my daily driver and I can feel the added power from the bbk but can't get it to rev when I rev it past a quarter it revs up strangely like its stalling but doesn't stall just wants to I am thinking it could be cam timing maybe due to when I installed the jug I had to push hard on it to get the spacers to push into the gasket . So I'm thinking that may have moved it from TDC ALTHOUGH IT DIDNT SEEM TO I LOOKED AT IT afterward seemed fine I just don't know what to do I have up jetted both jets and down jetted them too the only outcome is it runs or it doesn't. The only other thing I can think of is maybe the rings turned a tiny bit when I installed the jug I don't know please help!
|
|
|
Post by Cincikid on Nov 14, 2016 7:40:04 GMT -5
Probably not the rings? Any smoke? What jet sizes are you using? Stock air box and filter? The 3 hole in the cam were aligned with the head? You said you had to "push hard on it to get the spacers to push into the gasket" The gasket should have had cutouts that allow the spacers to slide through without squishing the gasket. Valve lash was set to .004?
"thinking it could be cam timing maybe due to when I installed the jug I had to push hard on it to get the spacers to push into the gasket "
The cam was installed after you torqued the 4 main and two side bolts? If so the timing should not have changed.
|
|
|
Post by Kasperthelost on Nov 14, 2016 11:01:37 GMT -5
The gasket I speak of WASNT the metal one it was the papery one and when I say push hard I mean hard enough to push the spacers thru the paper gasket. The cam was aligned although mine has more than three holes but I aligned it with the two holes horizontal and the top hole forward the other holes on it are for looks I imagine it was pretty obvious the three holes I had to align. Jet sizes are a 38 pilot jet and a 90 main. No smoke has tons of compression more than stock. And aftermarket air filter K&N style. Yes the cam timing was still the same after I torqued the two side bolts and the four main bolts everything still was aligned. It will run even pretty good just when I hit the gas over a quarter throttle it starts to sputter and sound kind of like a two stroke KIND OF LIKE THAT I say that cuz it's the best way I can describe how it's sputtering. It's like it wants to stall but doesn't. It also a brand new 20mm carb.
|
|
|
Post by humanshield on Nov 14, 2016 11:12:55 GMT -5
The gasket I speak of WASNT the metal one it was the papery one and when I say push hard I mean hard enough to push the spacers thru the paper gasket. The cam was aligned although mine has more than three holes but I aligned it with the two holes horizontal and the top hole forward the other holes on it are for looks I imagine it was pretty obvious the three holes I had to align. Jet sizes are a 38 pilot jet and a 90 main. No smoke has tons of compression more than stock. And aftermarket air filter K&N style. Yes the cam timing was still the same after I torqued the two side bolts and the four main bolts everything still was aligned. It will run even pretty good just when I hit the gas over a quarter throttle it starts to sputter and sound kind of like a two stroke KIND OF LIKE THAT I say that cuz it's the best way I can describe how it's sputtering. It's like it wants to stall but doesn't. It also a brand new 20mm carb. The paper gasket is precut and you should not have had to "push" anything through it. It is likely you damaged it. If so, you could either have an oil leak or oil starvation. I installed this size BBK on my scooter. Believe me, it will take some adjusting to get it to run properly. You will need patience. I'm very experienced with motorcycle tuning and engine building and I will confess even I got frustrated with it. It is a small engine and therefore less tolerant to tuning issues. I have over 4,000 miles now on my 50mm BBK and it's running as strong as new. Once you get it right, it's phenomenal. It is likely you need a bigger main jet. Get a Main jet assortment kit and start large and work your way down. Go back and re-check the timing chain. Usually if it off a tooth it will run ok but have little power. Not sputtering. If you have too much compression your engine will overheat and not last long. Beware.
You need a compression gauge to check the actual compression. The compression should climb as the rings seat. If the compression is over 190 - 200psi now, it will go too high once it is broken in. But right now, it sounds like you need a larger main jet.....try a 100 then go from there. DO NOT try to keep running it will too small a main jet...you WILL destroy it.
|
|
|
Post by Cincikid on Nov 14, 2016 11:12:55 GMT -5
Take the Air filter off and in small increments with your hand start to cover the air intake on the carb. Test with each movement. If it runs better then the main jet needs to be adjusted.
Edit: What he said.
Did your kit come with a head?
|
|
|
Post by Kasperthelost on Nov 14, 2016 11:48:49 GMT -5
Thanks I'll try those things
|
|
|
Post by Kasperthelost on Nov 14, 2016 11:56:49 GMT -5
I have a big valve head for a 50mm they didn't come together but I bought them online at the same time from the same company I bought the rest of the 50mm kit from advice from somebody else on here's advice I was going to just use the big with the stock bore but was told possibly by you my compression would be too low it may have been 90gt that told me that not sure. But anyway I went and bought the rest of the kit and now finally installed it I can feel how much power it has from the quarter throttle I can give it and I know it's going to be worth it onc I get it dialed in that's why I want so bad for that to be
|
|
|
Post by Kasperthelost on Nov 14, 2016 11:58:00 GMT -5
Also when I pushed the spacers thru the gasket I made sure it wasn't ripped or anything I was more worried that the timing move than tearing the gasket
|
|
|
Post by Kasperthelost on Nov 14, 2016 11:58:51 GMT -5
I know some about 50cc scooters and tuning them but one with a bbk now that's a whole different beast right there!
|
|
|
Post by Kasperthelost on Nov 14, 2016 12:10:02 GMT -5
I also was worried I may have over or under torqued the bolts I wasn't sure if that would affect anything?
|
|
|
Post by humanshield on Nov 14, 2016 13:40:40 GMT -5
Over torquing can result in them pulling out of the case.
Under torquing them can result in low compression, oil leaks and eventual damage to the studs.
Not sure what big valve head you got. There are several.
If it has 21mm Intake valve....perfect.
If it has 23mm intake valve....not enough compression.
Stock head....WAY too much compression
From your description I would be concerned about oil starvation issues. Again, you should not have had to push the spacers through the gasket...something isn't right. Unless you mean it was off by a fraction of a hair.If the gasket hole was too small and you left pieces of it in there, that can reduce oil flow.
(Oil flows to the head through those holes)
It would run "ok" for a while, but low oil pressure would guarantee an early demise for that motor.
|
|
|
Post by Kasperthelost on Nov 14, 2016 14:17:58 GMT -5
Well I guess that's probably what it is it has to be something to do with the gasket and oil pressure because it runs Lperfect with a 109 main and 38 pilot but when I hit the gas it sounds more like a 2stroke than a four anything after a small turn of the throttle ugh I KNEW I SHOULDN'T have forced it fml.
|
|
|
Post by Cincikid on Nov 14, 2016 14:44:07 GMT -5
Not shure the sound you're describing is caused by of the gasket. Any way you could upload a video? Either way I wouldn't run it without checking on the gasket, may be salvageable. You can get a inch pound torque wrench at Autozone or HF for about 20 bucks.
|
|
|
Post by Kasperthelost on Nov 14, 2016 18:55:32 GMT -5
I have an inch pound torque wrench and the bolts are all torqued to spec. And shoot I should have done that when I was running it earlier but now that you have said its starved for oil it does kind of seem like that to me now that I think about it it did seem warmer than normal when I ran it now I won't run it until I know for sure the gasket is good hopefully no rain tomorrow and I can open her up and have a look I may just wait til I have the new gasket in hand I ordered it today it should be here before Saturday hopefully sooner I HATE WALKING. AND FROM NOW ON IM GOING TO RECORD STRANGE NOISES. So I can use them for better explaination. I will say when I remove the valve cover there is oil inside there. That's why I was thinking it must be the carb but it can't be she runs too good except with throttle then she does the stuttering thing. The more I think about it the more lack of oil makes sense. This is why I love 49ccscoot! You saved me from ruining my hole engine. Thanks now when I install the new gasket I'll obviously use more finesse installing it.
|
|
|
Post by Kasperthelost on Nov 14, 2016 18:57:21 GMT -5
The sound is like its a struggling motor kind of noise kind of like bogging but different
|
|