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November 2019 Forum Retirement
Due to lack of extra personal time (and too much spam), I'm retiring the forum and setting it to a read-only state. No new registrations or posts will be accepted as of 11/09/19. However, all information will stay up and searchable. If you spend a few minutes searching, you'll find the answers you're looking for. We may re-open the forum next spring.

 #2906  by ckau
 Mon Jul 30, 2007 12:17 pm
If you switch to an aftermarket air filter such as the uni or another equivalent , you will need to go up on your jet size. These type of filters let in so much more air that a lean condition will occur. The gy6 150 is air cooled. A lean condition attributes to more heat and heat is a major cause of failure in these motors. Rings gone south and or valves failure can be attributed to overheating. Dirt from ineffective filters are another major cause of failure
Switching the main jet out is easy... loosen the carb from the intake , rotate it to give access to the float bowl on the bottom. remove the float bowl, up in the center, behind the float you will see the main jet. remove it with a flat blade screwdriver , replace with jet of choice, reverse procedure, your done! A 127.5 jet is a good average size most of the time with just a filter mod. Thats a big jump from the stock 110/114 jet but thats how much more air your letting in. It may run a little rich without exhaust mods , but thats better/safer that too lean. Exhaust mods are a different subject and you will probably want to go there after feeling this improvement! I personaly dislike drilling out jets cause you don't really know what you are getting as far as carb tuning. Plus Kehein jets are cheap! pick up an asortment from 120 to 135. 99% of the mods done on these motors will fall into this range
The jets can be had from most of the on line buggy/ scooter sites and at your local Honda shop. If you choose to use your local Honda dealer, take the old jet with you to insure correct match up. Tell them it's for a kehein 24mm, off a Honda 150 elite scooter. It may take a little pushing to get the kid behind the counter to do his homework. but a good parts man can fix you up. Here's a good pic of an aftermarket filter mounted using part of the stock yerf filter system. Avoid mounting the filter directly to the carb. some sort of inlet tube is needed to avoid turbulence at the carb throat. Turbulence at the inlet can cause erratic throttle control in a CV carb. Alot of people do whats called the "redneck mod" It's a 6 inch piece of chrome drain pipe found at your local hardware store, connected to the carb with a short piece of rubber pipe and 2 hose clamps . filter clamps to the other end. Simple, cheap, and very effective. This filter conversion, rejet plus a iridium plug [ NGK cr7hix ] and a muffler gut gives astounding results! Caution though... doing this one trick will lead to a fanacticle urge for more mods :lol:
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 #2907  by jtramsey4
 Mon Jul 30, 2007 2:00 pm
Thats what I am talking about.Straight facts and to the point.Thanks That let me know what I need to also.Picture worth a thousand words.You the Man.James :thumbsup:

 #2913  by ids
 Wed Aug 01, 2007 11:15 am
thanks very much for the help..this was great..

Now I need to try that on my lawn tractor, and see how much of a performance I get...

thanks again

steve

 #2923  by ids
 Fri Aug 03, 2007 1:05 pm
Hey ckau

you were right, I just came back from the Honda ATV dealer, and it was like pulling needles, they really didn't want to do anything, but after prodding I finally got something.

The only thing they has was a 125, and I was just wondering if you read this message again, do you thinhk a 125 would work, and you are right, it is much larger than the stock, that new airfilter must really let a lot of air in.

thanks

 #2924  by jtramsey4
 Fri Aug 03, 2007 5:57 pm
Let us know how it works out. James

 #2928  by ckau
 Sat Aug 04, 2007 11:05 pm
ids wrote:Hey ckau

you were right, I just came back from the Honda ATV dealer, and it was like pulling needles, they really didn't want to do anything, but after prodding I finally got something.

The only thing they has was a 125, and I was just wondering if you read this message again, do you think a 125 would work, and you are right, it is much larger than the stock, that new air filter must really let a lot of air in.

thanks
the 125 jet may be o-k IF you don't modify the exhaust. I suggest doing a plug check. Find a place where you can run wide open for approx. 1 minute. A straight flat road works best but use what is available to you. Install a fresh ,new plug. Run wide open for a minute, back off the throttle and cut the engine at the same time. coast to a stop , don't touch the gas. allow the motor to cool so you can safely remove the plug.The head is aluminum , It is possible to mess up the threads in the head if you try to remove the plug while it is hot. white= lean-bad. brown=good, black=rich, think of it as a color wheel white ,shading to brown , brown shading to black white not enough gas ,black too much gas. As I stated before too lean can hurt your motor, rich just looses some performance. Always safer to be on the rich side
you should be able to get jets through buggy depot,If not... here's a link to a site you can order from .http://www.bladepowersports.com/store.asp
Let us know what you find. :)

 #2930  by ids
 Sun Aug 05, 2007 10:44 am
Thanks ckau

I will try and see what happens, just wondering if you might know, on the bottom of the carb, looking at your picture on the left side, there is small air hose, when I did the conversion it came off, but I am unsure if it came off the air element box (I don't see an attachment), or did it just hang all the time,
any ideas?
thanks
 #2934  by ids
 Sun Aug 05, 2007 2:40 pm
Hi ckau,.

Thanks for the advise - the modifications all turned out fine, it seems all the hoses, even including the one from the bottom of the carb just hang, I guess that hose was hanging all the time, even before I took the air element apart.

For the spark plug, if I was to caution on the side of error, I would say it is whiteish, so i think I definitely need a bigger jet.

The mod is great though, there is so much more power with this simple mod. The cart's performance was incredible, so much so I thought I was getting whiplash (and I am 220lbs), but of course something had to happen, the chain came off, to fast on a dirt road. I recovered the chain, just not that one link that connects the two, know of any dealers?

thanks again for all the help

 #2935  by jtramsey4
 Sun Aug 05, 2007 2:43 pm
What all did you do to it? James
 #2936  by PGH
 Sun Aug 05, 2007 4:41 pm
ids wrote:Hi ckau,.

Thanks for the advise - the modifications all turned out fine, it seems all the hoses, even including the one from the bottom of the carb just hang, I guess that hose was hanging all the time, even before I took the air element apart.

For the spark plug, if I was to caution on the side of error, I would say it is whiteish, so i think I definitely need a bigger jet.

The mod is great though, there is so much more power with this simple mod. The cart's performance was incredible, so much so I thought I was getting whiplash (and I am 220lbs), but of course something had to happen, the chain came off, to fast on a dirt road. I recovered the chain, just not that one link that connects the two, know of any dealers?

thanks again for all the help
Glad you're up and running. I have to agree that this will be the biggest effecting mofication you will do your engine. I do recommend a precharger or filter sock over the UNI to keep it from collecting too much stuff kicked up by the rear tires.

The master link is for a #50 (industrial) or 530 (motorcycle) size chain. Hardware stores used to carry #50 chain, but in my area they have stopped. Any motorcycle or ATV dealer should have 530 or 530H master links on hand for about $2.