Shift kit + expansion chamber

[Spaz_Static]

Firstly, not entirely sure that this is the right location for this thread.

I'm planning on buying SBP shift kit, and expansion chamber. The one thing keeping me from actually making the purchase (other than the x-chamber being sold out presently) is that I don't know if with the chamber, if i would be running a "high compression" engine and need to go to the HD shift kit. As far as stats go, I have a 49 cc engine, straight head.

I also have a question pertaining to the spark plugs offered by SBP. I'm still running the stock plug, is there any reason I should switch to a different one? Are the only differences the temperature range, and what exactly does that mean anyway? As far as the temp range is concerned, I live near Raleigh, NC. (though I'll be being stationed at a presently unknown location after I make it through Basic Military Training and Tech School. I joined the US Air Force and go to BMT July 24th.)

Thanks,
-Spaz

 

[KCvale]

I'm planning on buying a SBP shift kit, and expansion chamber.
(Do I) need to go to the HD shift kit.
question pertaining to the spark plugs offered by SBP.
-Spaz

I know a thing or two about your questions ;-}

The difference in the price between the standard and HD shift kits is only due to the HD freewheel bearing in your right pedal crank.

If you look at SBP parts page you will see the difference in price between the two is the cheapie is $20, the HD is $70.

Unless you are ridding like a scared girl on a bone stock 48cc (which you won't be) you want and need the HD. In fact I don't think SickBikes even sells kits with those basic freewheels anymore.

The Sick X-chamber is awesome if you have the skills to install it, if you are more novice or rookie then just a $70 one piece like this:
http://www.jnmotorsbikes.com/product_p/jnm1189.htm

They say $50 but then whap you with $20 S&H but still about the same price as SBP's and much easier to install if you have room.


As for spark plugs go with the Iridium NGK BRP(6 or 7)HIX plug.
As you mentioned the 6 or 7 is the temp range.
In short that means how long the insulator to head metal contact is, which effects how well it dissipates heat through the head fins.

In cold weather you you want to keep the heat.
In hot weather you want to dissipate it.
The lower the number, the colder ambient temp it is geared to.

I run 7's here Phoenix.

One last thing...
What motor, bike and tranny are you putting it on,
And is this your first build?

 

[Spaz_Static]

Alright, HD kit it is.
As for the X-chamber, I think I am sufficiently skilled to install it. I have a bit of an aptitude for this kinda thing.
I think I qualify for the 6 range plug here, but I still don't see a reason for changing out plugs if the one I have is running fine. Is there any reason to change?

Motor is currently pretty much a stock china girl from BGF. I've changed gaskets and upgraded the bolts (SBP hardware kit), but that is about it. Bike is an older Mongoose, suspensionless frame. The rear shifter is a Shimano Acera X, if that means anything to you (front is Shimano Altus with Hyperdrive C sprockets, or something of that sort). I've pretty much got it adjusted properly right now. It sometimes hesitates a little in the middle gears, which I'll need to attend to. Never really bothered with anything other than the low and high gears as I didn't need to peddle except when starting out, and max speed to pull that hill without slowing as much. Attaching pictures of tranny, my avatar is a shot of the whole bike.

Also, yes, this is my first baby, and I doubt it will be my last.

 

[Spaz_Static]

More pictures.

 

[KCvale]

I think I qualify for the 6 range plug here, but I still don't see a reason for changing out plugs if the one I have is running fine. Is there any reason to change?

Surprisingly yes, especially with an X-chamber, those Iridium plugs put out one heck of a spark, enough to actually feel the difference.

Your front BB sprocket and cranks get removed, all you reuse is the pedals, and the whole front derailleur mech and control gets removed as well.
You can adjust the rear derailleur after you get the shift kit front sprockets on.

I find putting the rear shifter and clutch lever on the left handlebar, and the throttle and SBP dual-pull brake lever on the right handlebar works best.

Good luck with the bike upgrade and welcome to the fast lane ;-}

 

[Spaz_Static]

Surprisingly yes, especially with an X-chamber, those Iridium plugs put out one heck of a spark, enough to actually feel the difference.

Alright, good enough for me. When I ordered everything, I went on and ordered the plug. I figured, eventually my plug is likely to fail, this way I will at least have a spare.

Your front BB sprocket and cranks get removed, all you reuse is the pedals, and the whole front derailleur mech and control gets removed as well.
You can adjust the rear derailleur after you get the shift kit front sprockets on.

Yeah, I know the front cranks etc get removed, but I decided to go on and include the model type anyway. And as for adjusting the derailleur, yeah, adjusting after the front sprockets get attached makes sense. lol

I find putting the rear shifter and clutch lever on the left handlebar, and the throttle and SBP dual-pull brake lever on the right handlebar works best.

Way ahead of ya. That was one of the first things I ordered for my bike, about a month after I built it.

Good luck with the bike upgrade and welcome to the fast lane ;-}

Thanks! I checked my gear ratios with the shift kit (for gears 1 and 7) by finding which sprockets come with the kit, and making a spreadsheet. First gear will give me a ratio of 5.818 to 1, and seventh will give me a 2.286 to one ratio. Will my engine be able to pull that, or should I get a couple of other sprockets from SBP to reduce the ratio?

 

[KCvale]

Thanks!

You're welcome Spaz, with the fiber going to my server in Norway still down rendering all my web sites virtually useless but still in the mood to talk MB's I have time to share my advice with you ;-}

I checked my gear ratios with the shift kit (for gears 1 and 7) by finding which sprockets come with the kit, and making a spreadsheet. First gear will give me a ratio of 5.818 to 1, and seventh will give me a 2.286 to one ratio. Will my engine be able to pull that, or should I get a couple of other sprockets from SBP to reduce the ratio?

No need to worry about gear ratios with a 7-speed end drive, just make sure all the JS kit mounting and part size selections are right.

With the 3+HP these performance enhanced motors can push at my disposal I find less shifting to be better for me and why I run a 3-speed.

I also like to look at gear ratios in pedal relateable terms...
For example a typical single speed beach cruiser will turn a 26" back wheel 360° 2 times per 1 full 360° pedal crank, or 2:1.

With a 3-speed:
1st is ~1:1 or 50% under drive in comparison to a pedal rotation.
2nd is about pedal drive, or ~2:1
3rd can very but figure at ~3.5:1 or ~50% overdrive.

Best guess is you will find using 2nd to start the bike and get going, then to 4th, and only vary by single gears when tackling hills as the most comfortable way to ride without shifting the bike to death ;-}

 

[The_Aleman]

Spaz, if you can post what pedal sprockets you're thinking of running and your low- and top-gear rear sprockets, we can figure out your ratios better.

There are too many combinations to really generalize it. Let us pinpoint yours!

 

[Spaz_Static]

Well, my engine has what I counted to be a 10 tooth, and I am going with the stock kit sprockets, which I believe are a 17t jackshaft left, 10t jackshaft right, 44t driven by the shaft (on the pedal crank), and 36t driving my cassette. My 1st gear was, as I counted, a 28t, and my 7th gear was an 11t, again, as I counted. If my calculations where correct, that would be a 5.8177777778 to 1 ratio in first, and a 2.2855555556 to 1 ratio in seventh. Would you like me to go count the rest of the gears for us to figure that out, or you think top and low are sufficient?

P.S. Congrats on your 1500th post, Aleman!

 

[The_Aleman]

Overall ratio is much more telling, tho. From the info you've provided, I get this from the gear calc:

1st gear: 23.85:1, which comes out to 19.6MPH @ 6000RPM
7th gear: 9.37:1, which is 50MPH @ 6000!
(edit: 196 pedal RPM @ 6000 engine RPM)

HT has a 4.1:1 reduction built in * 1.7:1 on SBP mount = 6.97:1 at the right-side 10T

 

[The_Aleman]

Anyway, let me opine here. That's some pretty tall ratios there. You might be better off with a 30T inner sprocket. With a 30T:

1st gear: 28.62:1, that's ~16.3MPH @ 6000
7th gear: 11.24:1, that's ~41.3MPH @ 6000
(195 pedal RPM @ 6000 engine RPM)

If I were in your place, I'd run a 9T output, 48 outer, 36 inner. That would allow you to pedal at a higher engine RPM:

1st gear: 28.91:1, 16.2MPH @ 6000
7th gear: 11.36:1, 41.2MPH @ 6000
(163 pedal RPM @ 6000 engine RPM)

You'd have much better torque with the second setup including pedaling.

 

[KCvale]

Overall ratio is much more telling, tho. From the info you've provided, I get this from the gear calc:

1st gear: 23.85:1, which comes out to 19.6MPH @ 6000RPM
7th gear: 9.37:1, which is 50MPH @ 6000!

Those ratios actually work out very well in real life use.
If you tune your Xchamber for 4500-5000 RPM, which is cutting the straight copper piece in half, you will have the power to pull that ratio.

My 66cc Skyhawk with SBP Xchamber set like that, Iridium plug, HP plug wire and my ignition wiring, CNS carb with performance air filter, standard shift kit gears and 3 speed Nexus rear end I can start it on the first pedal and putt around at 5MPH and wind her all the way up to 45MPH if I bend over and tuck in from a dead stop in ~10 seconds, and I don't pedal along to help ;-}

Having built and rode a few high end 7-speed shifters I stand by my prediction you will start in 2nd, then use 4th and 6th for 90% of your riding, with 3rd and 5th only coming into the mix when wind or terrain are factors.

1st is pretty much just a show off gear, and 7th is for when you find yourself on a stretch of Autobahn type road, or in my case a nice 2 mile stretch of canal bank paved jogging/bicycling trail ;-}

 

[Spaz_Static]

Well, both are due in the mail sometime today.. probably while I'm at work, and I probably won't have time for working on it much. Working today, Sunday, and Monday. I might be able to work Saturday, but I promised the girlfriend i'd help her with some math project. Otherwise, everything is going to have to wait til Monday evening, or Tuesday.

As a side note, I'm working out a light system that wil take a 12v rechargeable battery. Haven't figured out much yet... stupid work. Hah.

 

[Death Machine]

Hey everyone,
I''ve been following this post and i was wondering how you got on with your build??
I've had the SBP Xchamber and shift kit for a while now. While there is a bit of head scratching involved installing them, they provide a lot of performance and fun.
Just a thought on your 12v rechargeable battery. I run li-po batteries with a 12v high powered LED. I get about 11.6v out of the batteries so no problem with frying the LEDs. The batteries are for remote control helicopters so they are light as, and pack a fair punch. I've run a Tacho (till i broke it) and some indicators (till i broke them).

Hope this helps

 

[Spaz_Static]

Think I'm going to go with a sealed lead acid as they are cheaper, but i'l be hunting ebay and checking a couple of local stores.

As for the build? Well, haven't even touched my new accessories except for making sure I got all of them. Reason being, I haven't had much time lately, and primarily because my electrical system crapped out. I'm getting a weak spark... when it does spark, and I haven't gotten much diagnosis done, been waiting on replies here on the forums, but it is going slow. I'm going to try out a couple things later today, and if its a no-go, and there still aren't any helpful replies in any of the threads I've been checking, I'll just order a new mag and CDI.

 

[The_Aleman]

Those $18 CREE's I bought a bunch of are great, but even the 2 like Jason runs which are great won't light a reflective street sign in broad daylight like these new systems can with one light can for the same price.

That's pretty funny, IMO. I have a pair of $8 Mwave blinkers that make street signs blink, night or not.

 

[KCvale]

That's pretty funny, IMO. I have a pair of $8 Mwave blinkers that make street signs blink, night or not.

$8? At a yard sale or something? They look like they go for $30 on-line and use regular AA batteries that aren't included, and maybe put out 300 Lumnes with 5 or 7 old old style LED's right?

CREE T5 and T6 high power LED's and the cool Lithium Ion rechargeables to power them I am talking about would just flat blow you away they are so cool Aleman, and the lights I buy now come with the battery(s) and a charger for them.

I have half a bookcase shelf full of those 'old style' lights and they are better than nothing, just not near good enough for my piece of mind anymore, my old battered body just can't take another major spill so by god I'm gonna make sure only a blind man won't see coming from 1/2 a mile away in broad summer daylight ya know?

I just share the links and my opinion on the cool bargain stuff I find with you guys, all I get out of it is the piece of mind I get out of sharing, especially when it comes to riding safety.

A daytime blinking light, ANY front blinking light, will improve your safety, I am just blown away with how much more visible I am on the road to others with these things ;-}

 

[Spaz_Static]

Started working on assembly of the shift kit, but had to go to work and didn't get far. I'll hopefully be finishing up later today. After I get it adjusted properly, I'll begin with the x chamber.

 

[Spaz_Static]

Life brings interesting stuff with it sometimes. My girlfriend got backed over by our friend in his GMC Sonoma. We had to take her to the hospital, where they said she was surprisingly ok. Road rash, chipped tooth, and a single broken rib, and that was the extent of her injuries. Anyway, she's back home after spending one night at the hospital and I'm able to resume work.

Installation of the new crank was a pain. The new one didn't want to screw in, but we managed to get it in... don't think it will ever be coming out again though. Now I'm on the brackets for the lower chain adjuster and none of them are the right diameter. They are all etched with 1 1/8 inch, like I measured my tube for and ordered, but when I measure them, they turn out to be 1 1/4 inch diameter. Suggestions? Should I use them anyway? SBP seems to have. Gotten them from Napa Autoparts, should I take them in with a ruler and ask them to get me some brackets that actually measure 1 1/8 inch regardless of what is etched in it?

Edit: attached picture.

 

[killercanuck]

Glad your girl's okay, that sucks. You should email SBP to warn them, and see if they'll send you the proper ones. Maybe free. Taking a ruler to Napa or wherever is a good idea too.