I am having trouble getting this thing to run aftet i installed a parts ace top end rebuild kit. The only luck i had was to spray starting fluid directly into the spark plug hole and it ran for 4 seconds without the exhaust manifold connected or the air filter. Seems like lack of air or too rich. Now the one thing that is different with this cylinder is there is no port to hook my petcock vacuum to the cylinder.. i figured the petcock shouldnt matter if i have fuel flowing to the carb on the prime position. Does this thing have to run off the petcock in the on position and functioning or something? Is it flooding out on prime? Shouldnt the carb float bowl be metering that? I set float bowl to manual specs...

 

I went through the same thing, just block the petcock and run it on prime. I guess in china they have a different petcock.

 

Linmax and Necht made LT50s, both firms used normal taps instead of the Suzuki vacuum one, in fact Necht used the tap from a Honda GX120 industrial engine, (it won't fit the Suzuki tank though).

 

If it runs on SF you're almost there...I like the above suggestions...just confirm gas flow to the carb and you should be good-to-go. If the carb bowl is full and plug still dry after cranking then you may have an intake issue (no pulse to draw the air/fuel into the cylinder)...easy to test pulse...just cover air side of carb with fingers/hand...you should feel the "tug" when you crank it over...


If bowl is full & pulse is strong, you then have a clogged jet(s)...

 

Ok seems like there is not much pull even though compression is at 100psi.. so what causes a bad pulse to draw? Is this aftermarket cylinder bunk?

 

After a complete rebuild of my sons 50 I noticed little difference in the compression from pulling on the recoil. Shortly after the rebuild I removed the head again and milled down the head with my belt sander. I really have no idea what the final compression numbers are, no before and after numbers to compare. Don't know, don't care. I'm sure I will get slammed for this on the forums but I am 100% sure the motor runs better, has a noticeable increase from idle to midrange and is more responsive across the entire range. It stars better too. I also noticed the pull starter have more resistance when the piston is approaching TDC. This surprised me, it was very noticeable. I believe the stock comp is very low, something like 7.5:1 or 8. I would be happy if the backyard head trimming bumped it to 9 or 10:1. I always use non ethanol fuel and I believe its 91 oct so I feel safe on pump gas @ 10:1. May want to give that a try for a free 20 minute upgrade. For the petcock, I think I remember reading somewhere the blaster petcock bolts right up and is on/of/res too. It may have been a banshee, I don't remember, it was a few years ago when I was considering changing it. Probably never will, I run it on prime with no issues, the motor gets used at least once a week. I hope this helps, good luck.

 

100psi seems a little low for a newly overhauled engine, but I think it should fire up on that. Are you sure the float is working, I have had an LT50 that didn't get enough fuel because the float needle didn't open enough, and one that didn't get fuel because the gasket was catching on the float.

I believe a blown crankcase seal can reduce inlet suction, but have never needed to fit one myself.

 

Yea im beginning to think it may have something to do with the float. It does have a very small vacuum on intake not sure how much it shoulf have. I tried to adjust it to specs in manual and it wasnt letting any fuel in at all (Dry bowl).Looks like the previous owner was messing with it cause its kinda bent up. I straightened it out and now its leaking fuel out the overfill.. Is this thing extremely sensitive to float bowl level? Like 1mm up or down is gona keep it from firing? Cause its not even sputtering.

 

Yea i have been thinking it may be compression also but others have said it should run on 100psi. At least fire... Thats good to know in the future though for a good performance upgrade...

 

I just ordered a new carb off ebay to rule out any carb issues.