Bike too slow

[OTP]

if you go to sickbikeparts.com and look on the right side, you'll see jets for these carbs are his best sellers.

 

[KCvale]

Maybe it's just my location in the desert, but I have NEVER had to re-jet a carb.
Ever.

 

[Deleted member 12676]

If the plug is black then it needs a smaller main jet.
a restrictive air filter (stock) can also cause it to run rich. I made my own out of a foam lawn mower filter.
I cut it up and glued it together with silicone sealant. It stays together but you can't use gasoline to clean it, only soap and water.

 

[Steve Best]

Don't run without a filter. Do like Jag did or get an oiled gauze filter, or even keep running the stock one. No filter will equal no cylinder very soon.

Steve

 

[Frankfort MB's]

Don't run without a filter. Do like Jag did or get an oiled gauze filter, or even keep running the stock one. No filter will equal no cylinder very soon.

Steve

done it for about 150 miles but I ride on the road and nothing too bad yet. I probably shouldn't but it's fine for quick testing just don't do it in really dusty or dirty conditions

 

[SEGACDX]

About a week ago I bought a 2-stroke 80/66cc bike kit. I installed it and after startup problems at first I managed to get it running smoothly, the only problem is, it is way too slow. It struggles to stay at 20mph with the throttle wide open. I checked the carb and the throttle runs fine, so it's not that. I'm using 20:1 oil to fuel on a 26" mountain bike. PLEASE HELP!

Alright I've been reading these replies to your question. What will fix your problem right away is to move the spacer on the needle in the carburetor from the third from the top to the Second notch, this still make the engine run leaner and a lot better than the stock option.

Here is a great guide on doing that: http://motoredbikes.com/threads/nt-carb-tuning-basics.24867/

Do not remove your air filter that is just a stupid idea and will not help you one bit if a small rock or even some dirt particles get in there you will have a lot of unnecessary wear. Go get yourself a aftermarket air filter if you really want to replace it.

Like someone Said run full synthetic 2 stroke oil 32:1 about 157ml per 5L, this is the ratio I have used for years and I find it works the best. Replace the stock engine bolts, sick bike parts has a kit for that but you can use 12.9 Grade steel M6 socket cap, 40mm, 25mm and 35mm to replace all the engine bolts get about 12 of each so you have extras and get some locktight red to keep them from vibrating loose this causes air leaks and loss of power, it happens super fast on these engines within a few short rides. You also get the bolt kit from Sick bike parts but it's not the strong stuff only grade 5 so your better off getting the 12.9 grade stuff from fastenal, plus it's much cheaper.

Links to everything I mentioned.

https://www.permatex.com/products/t...permatex-high-temperature-threadlocker-red-2/
https://www.amazon.com/Permatex-272...sr=1-2&keywords=High+Temperature+Threadlocker
https://www.fastenal.com/products/details/39571term=m6+40mm&r=~|categoryl1:"600000 Fasteners"|~ ~|categoryl2:"600039 Sockets"|~ ~|categoryl3:"600040 Socket Cap Screws"|~ ~|sattr06:^"Class 12.9"$|~
https://www.fastenal.com/products/details/1139570?term=m6+35mm&r=~|categoryl1:"600000 Fasteners"|~ ~|categoryl2:"600039 Sockets"|~ ~|categoryl3:"600040 Socket Cap Screws"|~
https://www.fastenal.com/products/details/1139568?term=m6+25mm&r=~|categoryl1:"600000 Fasteners"|~ ~|categoryl2:"600039 Sockets"|~ ~|categoryl3:"600040 Socket Cap Screws"|~
http://www.sickbikeparts.com/catalog/product_info.php?cPath=22&products_id=43

Some good oils recommendations:
https://www.amazon.com/Lucas-Oil-10...682900&sr=1-27&keywords=Synthetic+2-Cycle+Oil
https://www.amazon.com/Castrol-Power-TTS-100-Synthetic/dp/B001KOHX0U
https://www.amazon.com/Royal-Purple...8682873&sr=1-1&keywords=Synthetic+2-Cycle+Oil

I've been using that Lucas oil Snowmobile fully synthetic for a bit and it's killer stuff and a good price where I live, you can use it in al 2 cycle applications for air or water cooled engines.


Grab yourself a new spark plug, NGK B6HS, BP6HS, BRP6HIX are all great options but I personally Recommend the BRP6HIX as it is an iridium plug so it will not foul easily and will last a lot longer than standard plugs.

https://www.amazon.com/NGK-B6HS-Standard-Spark-Plug/dp/B0000BXHSP
https://www.amazon.com/Parts-Direct-2814-Spark-NGK-BP6HS/dp/B006O0FGKE
https://www.amazon.com/NGK-BPR6HIX-...F8&qid=1468680773&sr=1-1&keywords=NGK-BPR6HIX

Consider coating your aluminum head gasket in Copper spray as gasket or Ultra copper RTV, this is a super effective way of stopping head leaks on these bikes and the RTV is good for making all kinds of gaskets.

https://www.permatex.com/products/g...rmatex-copper-spray-a-gasket-hi-temp-sealant/
https://www.amazon.com/Permatex-806...8681201&sr=1-1&keywords=Copper+Spray-A-Gasket
https://www.permatex.com/products/g...aximum-temperature-rtv-silicone-gasket-maker/
https://www.amazon.com/Permatex-818...8&qid=1468681249&sr=1-1&keywords=Ultra+Copper

I hope that helps if you need anymore help feel free to ask.

Happy Motoring!

 

[gary55]

In Prescott Az. elevation is 1 mile. I have to re- jet NT carbs. With a . delorto #68. It's a 5mm jet. If you are from 4500 to 5500 ft. in elev. this would be a good place to start. With this set up at 5200 ft. most engines like the c clip on the second notch down from the top of the throttle needle. Don't know what your elev. is, but like OTP said you can get the jets at sickbikeparts.com. While your there get one of their ADA racing air filters. They work great, easy to clean, last longer than your engine will "especially if you run with no filter", and hell they even look cool. You are using to much oil. 4 Ozs. full synthetic per gallon after break in. Steve is dead on no filter means no cylinder real soon. KCvale is in Phx. so if you are at or close to sea level you should be able to adjust needle settings without re-jetting.

 

[Frankfort MB's]

What's up with the no filter issue??? Ive ran mine like that for about 150 miles no issues. I just haven't rejetted it yet (which I need to do)
A quick 1-2 mile ride will not hurt it (unless your in a rocky dusty area)

I was just saying to use it as test to see if he was running rich. Quick easy test.
NOT PERMANENT

 

[Frankfort MB's]

What's up with the no filter issue??? Ive ran mine like that for about 150 miles no issues. I just haven't rejetted it yet (which I need to do)
A quick 1-2 mile ride will not hurt it (unless your in a rocky dusty area)

I was just saying to use it as test to see if he was running rich. Quick easy test.
NOT PERMANENT

Besides, a cylinder isn't that expensive or hard to replace if something did go wrong (Which shouldn't happen)

 

[WINDY CITY BOB]

What's up with the no filter issue??? Ive ran mine like that for about 150 miles no issues. I just haven't rejetted it yet (which I need to do)
A quick 1-2 mile ride will not hurt it (unlessi ha your in a rocky dusty area

I have done test runs without a filter also never had a problem

I was just saying to use it as test to see if he was running rich. Quick easy test.
NOT PERMANENT