Shift kit + expansion chamber

Spaz_Static · Apr 7, 2012

Yeah. She's lucky.

Yeah, shot SBP a email letting them know, took the parts to Napa with my ruler and guy said "yep, that's not right. Unfortunately we only have 1 1/2 inch clamps in this store." Sad face.

Spaz_Static · Apr 8, 2012

Apparently that is the right size clamp, I just need to tighten it down pretty good.

Next issue, the crank sprockets seem to have a bit of a wobble to them. I haven't figured out yet if its the crank spindle, the freewheel adapter, or the crank arm. The sprockets look pretty true, and I. Don't think its the freewheel as that spins on the crank arm fine... so I think its either the spindle or the crank arm.

Spaz_Static · Apr 8, 2012

Rotated the crank arms 90 degrees on the spindle and it seems like the position of the wobble relative to the crank arms has moved, leading me to believe it is the spindle that is off a bit.

killercanuck · Apr 8, 2012

Doh! That sucks, hope you have a spare spindle kicking around. If not head to the junkyard

Spaz_Static · Apr 8, 2012

I'm not even sure if its enough to worry about... its about 2 mm at the toothed part of the sprockets. Is that enough to throw a chain? I'm kinda leaning towards not, but i'd like another opinion.

killercanuck · Apr 8, 2012

hm, can you put it in a vice at all? I wouldn't recommend torching it, that'll make it brittle, and that's where all your power is transferring through...

But, 2mm might not be enough to worry about, well, until you start doing high-speed runs. Then I'd worry... You can always try it, but bring a backpack with tools to get it back on if it(chain) does jump off.

Pedal around for a bit before even firing her up, just to be sure it doesn't 'half-skip' and lock up. If that test goes good, let'r rip!

A little wobble will get you around well enough, but to be safe you'll want to replace it sooner rather than later.

Best of luck!

Spaz_Static · Apr 9, 2012

Pablo said 2mm was normal, or at least within acceptable parameters (paraphrased), so I finished hooking everything up and went out to test connections, allignment, etc...

Not so good. I think my clutch died..? With clutch pulled in, things spin a bit and then start locking up. Gearing on the pedal crank and jackshaft look fine though, so that leaves the engine and its components. I'm not entirely sure where to go from here but to follow my clutch suspicions. I think Norman has a thread about tearing down a clutch so I'll check that out. In the mean time, suggestions?

KCvale · Apr 9, 2012

killercanuck said:
hm, can you put it in a vice at all? I wouldn't recommend torching it, that'll make it brittle, and that's where all your power is transferring through...

But, 2mm might not be enough to worry about, well, until you start doing high-speed runs. Then I'd worry... You can always try it, but bring a backpack with tools to get it back on if it(chain) does jump off.

Pedal around for a bit before even firing her up, just to be sure it doesn't 'half-skip' and lock up. If that test goes good, let'r rip!

A little wobble will get you around well enough, but to be safe you'll want to replace it sooner rather than later.

Read that again, print it out even to remind you.
This is motor power you are transferring to the pedal side so everything on that side has to as perfect as a direct drives side meaning sprocket alignment and chain tension.

It would really help if you had some close up pics and descriptions of what you are using for a bike and the build.
Troubleshooting on-line is hard enough with good pics, darn near impossible totally blind no matter how many you have built.

Start with your motor. What and how big?
As for the shift kit, is it the newer shift kit with a 1 piece mount bracket or the older style 3 part?
Are you POSITIVE you have the kit mounted to the motor right?
Did you get the HD Freewheel bearing or the crappy standard pedal one in those old kits they only sell for stock 48cc use?

If the bike was in front of me I could most likely diagnose the problem in less time than it took me to write this post.
I can help, but not without some effort on your part with some detailed info and pics

Spaz_Static · Apr 9, 2012

In the first post, I mentioned a little about the engine, its a 49cc straight head from boygofast, no name or identifying info on the engine. I have a NT carb, currently have the stock exhaust, and a NGK iridium spark plug. I can't give much more about the engine unless I am told where I could find a model number or anything printed on it (and I'm pretty sure the exterior is blank with no identifying marks).

My bike frame is a mongoose hard nose and tail. There is a pic of a potentially identifying sticker on it in this album on my google+ as well as a shot of the engine. I'll see if I can get more pics later, I'm literally making this post in bed lol
https://plus.google.com/u/0/photos/fromphone/5729579017664339826?tab=8X

As for the shift kit, it is the HD freewheel, and the 1 piece engine mount. Here are a couple videos of the wobble, as best as I could capture it.
http://www.youtube.com/watch?v=uvb7dN24qp8
http://www.youtube.com/watch?v=kn_dzTssCXA

Spaz_Static · Apr 10, 2012

Been out test riding it again after checking on a couple things, and I fixed the problem I was having thati thought was my clutch. It turned out it was several things together. The new bike chain had a couple stiff links from where I had to adjust the length (causing the chain to pull more taught at points, wasn't a major cause of the issue, but still something that needed to be fixed), there was a burr I missed on the engine, where the spacer for the rear mount goes (this was the cause part 1, it was pushing the mount to the right of the engine slightly), and the engine chain was hitting the rear mount and was what was causing the locking up. There is still the wobble in the pedal crank, but it didn't cause any problems whatsoever on my tests.

Next, I think I get a new mag or cdi as I'm still having a little trouble getting the engine to run quite right. Sometimes it doesn't want to start up, sometimes it will start fine but run poorly, and other times she will fire right up and putt along rather nicely.

Then after I get that sorted out, it will be time for attaching the x chamber.

killercanuck · Apr 10, 2012

I wouldn't worry about that little wobble until you get near the sound barrier

Sounds like you had an 'interesting' install. They can be finnicky, but once dialed in its all gravy

That sucks it doesn't want to run right. Especially now that the shift-kit's doing its thing.

How old is the gas in the tank? Ethanol gas water build-up maybe? It's weird that it would randomly run great then poorly.

gl.

Spaz_Static · Apr 10, 2012

Gas is maybe as old as a month. I have a two gallon tank that I fill and put oil in just for my bike. Should be all gas, no ethanol. I think there is a bad connection either in the CDI or mag, hence the inconsistency (I think someone suggested that in one of my other threads), or I just killed one by running lights off the engine. Carb is clean, so I really don't think there is a build up of anything.

Rocksolidperson · Apr 11, 2012

i think i would die trying to start my engine as i have a billet machined high comp head, reed valves & the sbp xchamber here http://www.youtube.com/watch?v=tR4dqSf16xE

Spaz_Static · Apr 11, 2012

So, the engine chain was stiff and what was casing the locking up. After I filed fown the casting flash, the chain was extreemly loose. I put one of the t spacers in and it made it better. I started to test it to make sure it was still working well and the chain started to bind up on I think the engine's sprocket and got extremely tight again. I left it alone over night as it was really late. This morning it had loosened back up, and when I started to test it again it got tight, but I checked bolts and tightened them a little and it seemed to loosen the chain slightly but its still catching on the sprocket. I'm thinking I might need to remove a spacer from the jackshaft, but I'm afraid if I do so the chain will start hitting the engine mount again.

I oiled the chain too. It sprayed the mount with oil, I guess from the vibrations of it catching the sprocket teeth wrong. I'm a little lost on what to do.

KCvale · Apr 11, 2012

Spaz_Static said:
Then after I get that sorted out, it will be time for attaching the x chamber.

Actually you may want to get that Xchamber on right away as the carb needle setting will usually change, you can run a leaner gas/air mix (needle set a little lower into the jet) with the X as it shoves unspent fuel back in.

You may just find she runs like a banshee as soon as you put it on ;-}

It is doubtful your have a bad CDI or magneto, they are almost always a go/no-go thing with no 'kinda goes sometimes' way of operating with one exception of course is loose wiring that can be effected by vibration or moisture, or maybe even a loose/cracked plug wire connector cap.

It sounds like you are getting close, it get's exciting doesn't ?
Of course it does ;-}

Spaz_Static · Apr 11, 2012

Haha, yeah, it is exciting, but also a little frustrating. I wish she would just work for me.

And so far today, engine won't start at all. I've been up and down the street for probably half an hour total today and it just won't go.

Spaz_Static · Apr 11, 2012

I think the mag is toast, or as someone said in the thread "testing a magneto" I need to resolder the ground for the blue wire or something. Problem is, I have no idea where that is, particularly since my mag was wrapped up in some plastic mesh crap. I'm afraid to tear it off because I don't know if I would end up ripping some wire wrappings or not.

Spaz_Static · Apr 11, 2012

Spaz_Static said:
https://plus.google.com/u/0/photos/fromphone/5729579017664339826?tab=8X

Spaz_Static · Apr 21, 2012

Got the xchamber on, and I swear it pulls harder now. Of course, now I need to work on my mag again as I couldn't get a good solder job on it. Between the iron being probably older than me, and the fact that the common ground is soldered to a huge chunk of metal, I couldn't get it heated enough to properly solder. I'm going to try a couple of alternative things for completing the circuit though, and will post my results.

KCvale · Apr 21, 2012

Spaz_Static said:
... the fact that the common ground is soldered to a huge chunk of metal, I couldn't get it heated enough to properly solder.

The magneto has 3 lugs.
The top lug pointing up is ground, it MUST be connected to the motor, if it's not the spark plug will have no ground and therefor can't spark.

The next lug down pointing left just below the ground is the blue CDI hot.

At the bottom pointing left is the white Aux wire, I usually cut that white wire off right at the lug.

Shift kit + expansion chamber

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