Author Topic: Needle Recommendations (Read 8779 times)

zcarlson12 · « **on:** October 31, 2013, 09:42:36 PM »

I recently picked up a 38mm Air Striker and am gathering mains and pilots. I know some people use different needles, what are some of the ones you guys would recommend for a ESR 310 on race gas? I'm going with mains 170-185 and pilots 40-52. Located in Kentucky if anyone is close and has a similar setup. Thanks.

C-Leigh Racing · « **Reply #1 on:** November 01, 2013, 09:38:35 AM »

Kentucky,
DGH or CEL, but do a compression check first.
Neil

zcarlson12 · « **Reply #2 on:** November 01, 2013, 10:59:04 AM »

Thanks Neil will do.

sameltoe · « **Reply #3 on:** November 01, 2013, 12:20:34 PM »

Those 2 seem to be a common choice.

Jerry Hall · « **Reply #4 on:** November 02, 2013, 01:59:41 AM »

Quote from: C-Leigh Racing;16258

Kentucky,
DGH or CEL, but do a compression check first.
Neil

There is a big difference in the initial diameter between the H and L at zero to about 1/4 throttle position on those two needles. What other engine specifications besides compression would influence you to choose one needle over the other?

zcarlson12 · « **Reply #5 on:** November 02, 2013, 02:42:12 PM »

Well bad news. I did a compression check on my freshly rebuilt motor, I have about 4 rides on it with probably 3-4 hours at the most on it, and the compression was at 155psi on my harbor freight gauge and 120 on autozone's loaned gauge. I hope it's just because of the quality of the gauges I was using but I'm not sure. I found my leak down tester so that's my next step. All cylinder head and base nuts are tight. Not sure what else it could be besides an air leak.

udontknowme · « **Reply #6 on:** November 02, 2013, 04:57:20 PM »

i never bother with gauges. besides youre using one from china and the other from taiwan. if everything is new and no leeks you should be good

udontknowme · « **Reply #7 on:** November 02, 2013, 06:57:15 PM »

i think you guys been listening to carlos to much

maybe jerry could chime in on the subject ?

my thoughts have always been static pressure is pretty much useless info, to me anyways. a ton of things influence it. varying gauges, altitude, porting. hell the pipe and carb size probly do as well. and possibly even the reed stiffness ? besides soon as the engine is running the cylinder pressure changes. so what does a static number tell you. not much that i can see.

some people use a pressure gauge as a quick and easy way to determine when the top end is wearing out and i can see the usefulness in that respect provided you always use the same gauge and dont make any engine modifications but still you should confirm with tool measurements and examining the suspected worn parts.

zcarlson12 · « **Reply #8 on:** November 02, 2013, 08:28:41 PM »

As soon as I get my head pipe off I'm going to do a leak down test. The motor ripped when I rode it with the 38mm TMX carb. All that I changed was putting the air striker on which started this entire reason for what I'm currently doing. After I put the carb on it wouldn't start so I took it off and cleaned it and thought while I have it that far apart I would do the compression test and other checks. It is a brand new piston and 72.25 bore, all new bearings and seals in the motor, new stock stroke new style Hot Rods crank, new Boyesen rad valve, new spark plug, and new race gas dome with fresh Sunoco 110. It definitely has more than 150psi compression because it kicks over harder than my Blaster that had a Baldwin ported national motor on the same fuel with a 34mm carb and over 150 psi compression. When I took the air striker carb apart it had a 52 pilot and 170 main but to me that doesn't matter at this point because it should still fire up so it may be an electrical issue as well. I'm confused but will head out to the garage tomorrow and see what I can find out.

udontknowme- I agree with you some what but to me with only 3-4 hours on a fresh motor it should definitely be over 155psi no matter what so I'm glad I decided to check it when I did. Hopefully it's just bad compression gauges. Would there be anything besides a air leak that would affect the compression that much?

udontknowme · « **Reply #9 on:** November 02, 2013, 08:57:52 PM »

well you were using 2 cheap ass gauges. most likely neither was reading correct. i doubt a airleak would have much influence unless it was a huge gaping hole. see if a local mechanic has a qaulity gauge you can borrow, still theres no gaurantee its correct but the odds will be higher than a cheap taiwan unit

if you got a big exh port it will have a large impact on static pressure. plus i think elevation is -5 to 7psi every 1000'

personally if the leakdown shows good i would ride and not worry about nothing but thats just me

pantera1975 · « **Reply #10 on:** November 03, 2013, 08:44:04 AM »

I uses a brand new Matco gauge and and pretty new Cornwell one from work a couple years ago on my motors 1 gauge said with a stock piston,head gasket never touched motor it had enough compression it over 180 psi the other gauge said I needed a rebuild and had below 145! what do you believe??? I run a 330 with a 39 mm, ATC 5 ESR pipe, full air box with the lid off and trx 9 porting with a 50/50 dome a cel pinged like crazy went to dgh and still pigs I just havent had time to try a ccl next I believe is what rsss396 suggested. I know alot of people run a 52 or small slow jet but in Wisconsin I run a 55 in the summer,but the ccl needle may make the 55 to rich.

zcarlson12 · « **Reply #11 on:** November 03, 2013, 09:47:13 AM »

Me too Martin.

Thanks for the help everyone. If the leak down checks out I'll keep running it but I just don't want to put it back together and first ride out it blows up because I didn't check something. I guess that's the 'labor of love' part of these R's. On a side note, what do you guys use to plug the exhaust flange for the leak down test? Tape it off? Plug it with a towel?

Skeans1 · « **Reply #12 on:** November 03, 2013, 09:59:03 AM »

Try a pipe test plug to plug the exhaust port.

Jerry Hall · « **Reply #13 on:** November 03, 2013, 09:59:03 AM »

Quote from: pantera1975;16372

I uses a brand new Matco gauge and and pretty new Cornwell one from work a couple years ago on my motors 1 gauge said with a stock piston,head gasket never touched motor it had enough compression it over 180 psi the other gauge said I needed a rebuild and had below 145! what do you believe??? I run a 330 with a 39 mm, ATC 5 ESR pipe, full air box with the lid off and trx 9 porting with a 50/50 dome a cel pinged like crazy went to dgh and still pigs I just havent had time to try a ccl next I believe is what rsss396 suggested. I know alot of people run a 52 or small slow jet but in Wisconsin I run a 55 in the summer,but the ccl needle may make the 55 to rich.

Does you engine ping at partial or full throttle?

rk88r · « **Reply #14 on:** November 03, 2013, 10:51:04 AM »

Pantera fellow northlander I run a cel in the summer, dej spring and fall, and I raise the dej a groove in the winter. dgh's and dgj's both run lean at half throttle on my midrange play bikes.
First letter: length of needle after the taper starts.
Second letter: 1/2-5/8 throttle
Third letter: 1/8-3/8 throttle