Faster Faster Faster !!!!

thepolarpandabear said:

Well I've built my bike kit, made all the adjustments and my spedometer on my smart phone has 26 mph as top speed, I'm in the 20 mph club and I want to go faster. I'm content with the pick up but I want more top end speed. I'm more on the thick side if you catch my drift.

My big question is what can I do to increase my top end other than changing my sprocket to a 36 tooth one.

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very catchy thread title! well, you prolly know theres a million threads on speed mods here. I've been reading my eyes out today, and have garnered some great new knowledge. I just watched a youtube video of a guy with a mountain bike style frame who had only done a couple simple mods, and not even jetted it. I'm not claiming these worked for me, but this is what he said:
1: abs plastic pipe ram-air setup on carb was a noticeable increase in power, (and this actually has piqued my curiosity. )"
2: he was using what looked like a 22 tooth sprocket! crazy! seems like a lotta pedaling before you see any power. pretty "no-torque" setup
3: he said he had gutted the exhaust. stock. not even an expansion chamber,
4: he had moved the needle up a notch to compensate for the ram air intake.

none of these sound like my gut instinct mods, but he claimed 45-53 mph. also looked to be about 17o lbs.

my setup bests me 35 tops.

1ocketbike expansion chaimber with 12 inch headpipe for torque
2: holes drilled in stock plastic air intake cover
3: 40 tooth sprocket
4: manic mechanic H.C. head
5: ngk bp6hs plug
6: 24:1 as I'm still breaking it in
7: needle at 3rd detent
8: im 6'3", 200lbs
9 ported intake manifold (helped smoothness)
ported exhaust manifold (not sure if it did anything)

I think I will try a 36 tooth just to see if that improves upon the 40t for top speed. she cruises comfy at 28 mph, then into the crazy shaky rev zone for the 30-35mph range. I'm thinking the pipe really has helped the engine run strong through the low & midrange, and the sprocket is the one thing thats holding it back on the top speed as far as things under the list of easy mods. My next steps would be opening up the transfer ports and widening the cylinder intake and exhaust, ports and perhaps triming the cylinder skirt , but that getting a little crazy. I think as few revs and rich as practical and you'll have a setup that wont cease on you. although after watching the video of the intended ceasure, I realized these things can take quite a beating. the guy ran WOT with no oil in mix for 3 minutes before it quit.

If your looking to get more out of your engine then you will need to get it in perfect tune (no 4 stroking). Here are just a few ideas to get you in the right direction...

- If you go with and expansion chamber then you'll need to rejet to get it running right.
- Performance mods (racing carb, ported manifold, high-compression, ect.)
- Get an NGK spark plug to replace you factory plug.
- make sure your chain in lubed well and is nice and straight.
- replace knobby tires with smooth semi-slick tires (if applies).
- ride tucked down like a crotch rocket MC

There are a few little things you can do for fairly cheap to get you bike running better. However in the end it comes down to the gearing. Nothing will effect your MPH better then a sprocket or an SBP shift kit. Please don't try to hit 35 on a 44T, , you will be between 8k-9k rpms and your motor will be toast before you know it.

I can hit 30mph with a 41 tooth sprocket, but Im also using 700 road bike rims.

thats dax has them his ad is on the side of the page what size sprocket do you have now

thepolarpandabear said:

I've already have a slant head is there any difference in the manic mechanic head ? I also have changed my spark plug ill look and see exactly but its not a ngk plug. Knobby tires are a need for me I do winter riding.

I plan to try a forced air ram intake out of pvc, and move tge needle up to. I'm definatley going to port my intake manifold. A good idea my gramps (ASE sertified) gave me is to relaxing the grease in the hubs of my tires. Switching to a 36 tooth sprocket too.

It looks like I'm going to be working on my bike all weekend...any one know where to get a 36 tooth sprocket with the 9 hole setup.

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first of all I've never heard of " relaxing the grease", but those ASE guys know stuff... heh heh.

the slant head has a tad more volume. Manic Mechanic head has a stepdown bevel that removes a tiny bit of volume. but everything is tiny with these. I'm not sure it's worth the money for the performance, but the combo of performance and the CNC look and quality is well worth it.

Lynn at Custommotoredbicycles.com has sprockets galore, but try a 40 before you go getting crazy and losing any rotl power.

and gap yur plug at .025 to start. I went a tad wider on a NGK bP6HS as well as the stock plug as a test. helps both plugs to gap them. helps both bikes to add NGK plugs to them. noticeable improvement. as well as

porting the intake manifold is a noticeable improvement and is an easy and rewarding thing to do.

all of these things are like pebbles in the bottle. remember this one?--

"there once was a crow who was thirsty. luckily he found an upright bottle of water, but with only a small amount of water Left in the bottom. the crow tried for hours to get his beak down the bottleneck to get to the water with no success. near death and desperate, the crow pecked at the ground. another crow landed, and began pecking at the ground. he then picked up a pebble and dropped it into the bottle. and then another. and then another. for the next few hours the crowes filled the bottle with pebbles, until the water was displaced and was finally close to the top and able for them to reach and drink with their beaks. it was not one giant pebble, but the many small ones, that achieved their goal".

I think all us Motorbike guys might just be crows!

if you are a bigger guy, you may want to think more about concentrating on increasing torque if you have ANY hills to drive up in your daily travels. at 26 mph, you should have decent torque. increasing top end usually means sacrificing torque, unless you go to an expansion chamber. i got lucky with my x chamber, it gave me a more top end and a significant torque boost. ten more miles an hour and i can climb most hills without pedaling. good luck.