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Rayman

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Hello everyone, I have a Tomberlin Crossfire 150 and I do not know what else to do to get it running correctly. Forgive me for the long post. I just wanted to be thorough. I have completed the following.
Replaced Top End
Adjusted Valves to Specs
Replaced with new gaskets
Replaced Intake Manifold
Cleaned Carburator and Jets
Adjusted float
Replaced Petcock
Replaced fuel lines
Added New Uni Filter
Adjusted Carburator RIch/Lean screw, adjusted to about 1 1/12-2 Turns back, idles at 1400-1500 RPMs with or without filter.
Replaced Spark plug and properly gauged
Replaced Coil/spark plug wire
Also tested for Vacuum leaks, but I will do it again, maybe I missed a leak somewhere, will let you all know how that goes.

Go-kart starts right up and idles at between 1400 and 1500 rpms. I can get about 6500-6850 rpms without the Uni airfilter on and it goes fine, but the minute I put the air filter back on my max RPMs drop to about 4500-4800 rpms and it is slow and sluggish. It doesn't backfire or sputter it just will not go above 4500-4800 rpms. It does not blow white smoke, but when I removed the plug after running it a while, the plug is black. It seems to be running rich, but I don't smell gas, but the exhaust side is a little wet with gas. Again without the air filter, I am gettig 6500 to 6850 RPMS. This cart is rated for 7500 RPM's. I think I can get that and a little more with new rollers, and replacing the CVT belt, and perhaps upgrading the clutch, but I don't want to do this until I can get it running correctly. Please advise any help would be greatly appreciated.

Very Respectfully
Rayman
 
Along with that . Trying to get the claimed : 7500 revs per minute .
Might just require a new machine when the engine Explodes !
@#Bring a Dust Pan . com :eek::ROFLMAO:
 
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flattop1 said:
Get rid of the filter . Put a stock one back on it .
Click to expand...
Thanks, will see if I can find a stock one, I looked but because of model, I think old air filter is hard to find. I assumed that a gy6 150cc would work with a UNI filter must be wrong. Others advised to get rid of stock filter for better performance, so here we are. Original air filter system was gone when I got it. Thank you for the quick response.
 
Skidude said:
If your plug is clean without the aire filter, then soots up with the air filter, there’s your problem.
Click to expand...
I will pull plug again and check it out, also will look for the stock air filter. It did not have it when I got it. Thanks for the quick response.
 
Rayman said:
Thanks, will see if I can find a stock one, I looked but because of model, I think old air filter is hard to find. I assumed that a gy6 150cc would work with a UNI filter must be wrong. Others advised to get rid of stock filter for better performance, so here we are. Original air filter system was gone when I got it. Thank you for the quick response.
Click to expand...
I helped a fella out same issue .
Used a briggs animal filter .
A peice of hose and a similar style paper filter
 
flattop1 said:
I helped a fella out same issue .
Used a briggs animal filter .
A peice of hose and a similar style paper filter
Click to expand...
Thanks, found a box and filter being sold separately, waiting to see if the box comes with filter, advertised is for a 150R so I asked if this was compatible with the 150. I think there was a difference in the frame that surrounds the engine. I don't know if that makes a difference when it comes to the correct fit. Also together they are more expensive than purchasing a briggs animal filter, if you know that would work then I would rather go that route. I am waiting for their response, might have to give them a couple of days. Also, I went to the forum you provided earlier, great information. I don't want to get into rejetting and such if I don't have to. U know at this point trying to take path of least resistance and all. Once I get running properly I will go to the next level and attempt some performance upgrades. I am ready to enjoy riding as opposed to tinkering. WIll keep you posted. Thanks you for helping out.
 
Can't remember if he had to stretch it or tighten the clamp more .
Measure the inlet diameter in inches . Ill look at a filter tommorow .
 
Rayman said:
I will pull plug again and check it out, also will look for the stock air filter. It did not have it when I got it. Thanks for the quick response.
Click to expand...
Hello Skidude, I pulled the plug after running it for 10 minutes with the filter on and it was black and sooty. I cleaned plug then ran without filter for 10 minutes and sure enough it was cleaner. I am trying to find the original box and filter and have an email out to someone selling one that they say fits a tomberlin 150r. I asked if it would fit the 150 and am waiting for a response. I think the frame around the 150 is smaller than the 150r but I am waiting to see. flatttop1 recommended a briggs animal filter but he needed to know the filter side diameter of the carb. It is 1 3/4 inches or 44mm. I am going to let him know next and also go on line to see if I can find one. I think the briggs animal filter is the cheaper way to go for now. I will let you know if I can get it running correctly. Thanks for your help.
 
flattop1 said:
Can't remember if he had to stretch it or tighten the clamp more .
Measure the inlet diameter in inches . Ill look at a filter tommorow .
Click to expand...
Hello, fllattop 1, I took the measurements on the filter side it is 1 3/4 inches or 44 mm. I will go online to see if I can find a briggs animal filter. Thanks again for the help. I will let you know if I can get it runinng correctly.
 
Good morning all. So I received the new filter. It is a cone-shaped paper filter, not like the foam Uni filter I tried earlier. Put it on fired it up and still no luck running properly. I cannot find the box and filter that it came with originally or a replacement that will work, but I don't know if that would matter anyway. Again runs great without the filter on and I am getting WOT at 7440 RPMs. Once I put on any filter RPM's drop dramatically. Still idles fine and starts up fine. I removed the carburator again cleaned it, jets are clear, float is set right, no tear in diaphram, looks good. I have adjusted the fuel/air mixture screw along with the idle screw and starts and idles @ 1500 RPM's, run great @ 1 1/2 turns to 2 turns back. I am at a loss as to what is going on. I rechecked for any vacuum leaks and cannot find any. What am I missing? The only thing I haven't replaced is the CDI, could that be the problem? Any assistance would be greatly appreciated.
 
I pulled the plug after running it for 10 minutes with the filter on and it was black and sooty. I cleaned plug then ran without filter for 10 minutes and sure enough it was cleaner.
This and the fact another filter acts the same leads me too believe the jets been changed . Especially since you received it without air filter .
Any chance there is a passage or hole getting blocked with the filter installed .
Cdi is highly doubtful thats the problem or it wouldn't run .
 
flattop1, thanks for the response. Both air filters are pretty much a straight shot and there was no blockage with the extension hose that I added with them. I will order jets, but I don't really know how they work or which ones to purchase, or which ones to replace so I will have to do some research and trial and error. Thanks for the quick response.
 
The main or the one with the big hole . Should try too see what it has currently .
Or adda small peice of rubber/plastic hose with a peice of nylon hose over the end see how it acts then . May have to run just a brass screen , depending on the amount of dust you have . No filter though is accelerated engine wear .
 
Yep, carbs can be finicky. I ordered a set of Main jets and pilots, so I will do some tinkering and see if this will make a difference. I did find an Airbox and filter for a Yerf Dog, and they claim it is compatible with the Tomberlin Crossfire 150, it's a little pricey so I think I will mess around with the jets and the filters I have already purchased before I go there. Thanks for the assistance and I will keep you posted on my progress. Jets won't get here until the end of November
 
Update: Alright, received Main Jets and Pilot Jets. Carb had a 34 small pilot and Unknown stock size for Main Jet. I put in a 32 small pilot jet and a 130 Main jet, and now the engine runs with the Uni filter on and gets to about 6100 RPM's WOT, much better than before. (Wouldn't get beyond 3100 RPM's with Uni filter on before so I'm making progress). The engine fires right up and idles fine, but it is sluggish getting to WOT. Once I get to WOT and release gas pedal the engine will die. It starts right up and I go through this process all over again. Also, when I turn the fuel/air mixture screw to the fully closed position the engine still runs and doesn't stall or stop at all. So I know I am getting too much fuel, running rich. I don't think the fuel/air mixture screw is broken but I will recheck it. Someone suggested the enricher is staying open. I will check the enricher/choke tomorrow to see if it is staying open, if so this would definitely be part of the problem no doubt. Either way, I am getting closer to having this engine run better. Does anyone have suggestions on what the proper Main Jet and the small pilot jet combination should be after I check out the fuel/air screw and the enricher/choke? Is it just trial and error with the Jet sizes?
 
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