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Post by scooter on Jan 19, 2015 18:39:54 GMT -5
I just put a new belt and variator on this 250 Qlink Communter Helix clone. This is the same bike I made the vacuum and fuel pressure test video on. It was running horribly at open throttle and wouldn't go over about 45mph. Now with the new variator it isn't cutting out like it was, although it still feels like it's on the verge. Now it does about 50mph or more, I didn't push it on these small streets, but it might do more. It did 46-48 up a fairly steep bridge. Do you think the new variator is loading down the engine more than the old one? Unless I accidentally made something right while pushing around on the air box, fixing a vacuum leak, I think it's just that the bike can't rev too high with this new variator on it, thus avoiding the rpm at which it would usually cut out. Before I put the new variator on, the engine did better when getting up to speed than it did once it was going faster. That is, it would cut out once it got going. Is this change in engine performance a clue to what is going on with this engine?
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Post by alleyoop on Jan 19, 2015 19:07:17 GMT -5
You are not explaining what is happening with the scoot. A 250 should be able to do 60+mph with no problems.
So at Wide Open Throttle what happens does it the motor make any different sounds, like POPPING or BRAT sounds.
If it has a tach what are the RPMS at wot.
Alleyoop
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Post by scooter on Jan 19, 2015 19:21:37 GMT -5
You are not explaining what is happening with the scoot. A 250 should be able to do 60+mph with no problems. So at Wide Open Throttle what happens does it the motor make any different sounds, like POPPING or BRAT sounds. If it has a tach what are the RPMS at wot. Alleyoop If you have a few minutes, could you look at these readings and this video I made of it running? That will probably be better than me trying to explain it with my limited technical vocabulary. itistheride.boards.net/post/83914/threadIt starts cutting out at about 7900 rpms at 2:40 in the video and again later in the fuel pressure test at about 8000 rpm at 6:03 in the video. |
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Post by scooter on Jan 19, 2015 19:28:55 GMT -5
You are not explaining what is happening with the scoot. A 250 should be able to do 60+mph with no problems. So at Wide Open Throttle what happens does it the motor make any different sounds, like POPPING or BRAT sounds. If it has a tach what are the RPMS at wot. Alleyoop If you have a few minutes, could you look at these readings and this video I made of it running? That will probably be better than me trying to explain it with my limited technical vocabulary. itistheride.boards.net/post/83914/threadIt starts cutting out at about 7900 rpms at 2:40 in the video and again later in the fuel pressure test at about 8000 rpm at 6:03 in the video. When I am on the road it cuts out at about 45mph, or was, and I have to back the throttle off to make it stop cutting out. |
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Post by alleyoop on Jan 19, 2015 19:37:24 GMT -5
The motor sounds good, it is just breaking up at near 8000k but that is pretty high rpms for a 250 and normally you will not get those rpms under load(when your riding it) anyway. You normally do not run the 250s at that high of rpms. What I did hear is rattling from the Variator weights I would guess and if your complaining about top end speed I would check the weights.
Alleyoop
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Post by alleyoop on Jan 19, 2015 19:41:42 GMT -5
If when your riding it it runs good at around 7500 rpms that is where they make the most horsepower. If you have a tach on it the REDLINE will be marked starting at 8000rpms.
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Post by alleyoop on Jan 19, 2015 19:55:36 GMT -5
When I am on the road it cuts out at about 45mph, or was, and I have to back the throttle off to make it stop cutting out.
We were typing at the same time or whatever but I just read what you said the above sentence.
On the road at what mph does it start to cut out now?
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Post by scooter on Jan 19, 2015 19:57:03 GMT -5
If when your riding it it runs good at around 7500 rpms that is where they make the most horsepower. If you have a tach on it the REDLINE will be marked starting at 8000rpms. Thanks. I just put on a new belt, variator, and weights. It's running better now but I haven't made a top speed run on it yet. I don't know what the RPMs are under load. I'll have to put that tach on the bike somewhere and see what I'm getting on the road. |
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Post by scooter on Jan 19, 2015 19:58:47 GMT -5
When I am on the road it cuts out at about 45mph, or was, and I have to back the throttle off to make it stop cutting out. We were typing at the same time or whatever but I just read what you said the above sentence. On the road at what mph does it start to cut out now? It didn't cut out with the new variator on it. I will put the tach on it and make a top speed run tomorrow and see what happens. |
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Post by alleyoop on Jan 19, 2015 20:01:30 GMT -5
Great, it should do over 60mph at the very least.
Alleyoop
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Post by jerseyboy on Jan 19, 2015 20:38:44 GMT -5
If it cuts out with throttle wide open then comes back to life if you roll off the throttle a little I think you need to up jet a size or two...maybe
Starving for fuel,,could be a restriction in the fuel delivery dept. also..
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Post by bandito2 on Jan 19, 2015 21:17:54 GMT -5
If it cuts out with throttle wide open then comes back to life if you roll off the throttle a little I think you need to up jet a size or two...maybe Starving for fuel,,could be a restriction in the fuel delivery dept. also.. A restriction in fuel delivery is what I was thinking too. If there is a fuel filter in the line somewhere on the way to the carburetor, it could be plugged up some. Happens sometimes with the Reflex scooter (which uses an elec. pump) and the cause is sometimes rust from the tank. Condensation would make for rust on the tank bottom and rust bits would get picked up and clog the filter. You might check to make sure there are no kinks in the fuel line as well. |
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Post by jerseyboy on Jan 19, 2015 22:13:27 GMT -5
If you have a little rust in the tank,,they make a great tank liner kit that works very good!
I used it before and it seals up pin holes too,,really good stuff,,think Harley uses it in all their bikes at factory for preventative measures.
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Post by alleyoop on Jan 19, 2015 22:33:01 GMT -5
Yea that is what I want to see how it now runs at WOT AND AT WHAT RPMS. He has not done that yet, so we don't know if its fixed or if it still has a problem. If it acts up then do like Jersey said whine the sucker up and WHEN it acts up back off the throttle about 1/4 of a inch and hold it there. Then pay attention to what the motor does:
1. If it speeds up it is LEAN needs more fuel
2. If it just sputters some more and or settles down then it is RICH to much fuel.
This trick of the trade will tell you what the motor needs IF it acts up it may just now run fine.
Alleyoop
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Post by scooter on Jan 20, 2015 16:22:38 GMT -5
Yea that is what I want to see how it now runs at WOT AND AT WHAT RPMS. He has not done that yet, so we don't know if its fixed or if it still has a problem. If it acts up then do like Jersey said whine the sucker up and WHEN it acts up back off the throttle about 1/4 of a inch and hold it there. Then pay attention to what the motor does: 1. If it speeds up it is LEAN needs more fuel 2. If it just sputters some more and or settles down then it is RICH to much fuel. This trick of the trade will tell you what the motor needs IF it acts up it may just now run fine. Alleyoop It goes 50mph at 5600rpm and then begins to sputter again. It stops sputtering when I let off the throttle a little. 48 is about as fast as I can go before it starts sputtering again. Better than it was, where I could barely get to 45mph and now the sputtering isn't as harsh. I'd say it feels boggy. I'm also getting poor gas mileage. I'm going to readjust the mixture screw, or whatever that screw is on the bottom of the carb, and maybe drop the jet size. My new electric fuel pump will be here tomorrow, so I may hook that up too, and see what difference it makes. I have seen the gas coming out of my current pump line and I'd say the pressure is too low, but from what you are saying, and the fact that there is gas in my intake, I'm thinking I'm running too rich, and possibly suffering fuel starvation as well. What do you think causes the sputtering? |
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..BAD TO THE BONE..
