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Old 09-13-2008, 05:22 AM   #1
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Default Weird low end bog.

I have a go tech 3 port race, with Dynamite Platinum 1/8 053 MidRange pipe.

If I let the buggy idle for a few second it takes off right away with no bog or hesitation. When I am driving if I can keep my speed and RPM up it still has good take off with no hesitation. But when I come up to a more technical slower portion of the track and need to slow down, when I get back on the gas, hard or soft it has a bad bog with lots of hesitation. When I get back on the gas and keep my RPM up no bog. This happens when the engine is warn or cold

I have been leaning out my bottom till it affected my idle and back it off an hour or 2.

I think it might be my clutch but I would assume if itís the clutch I would have this bog at all times?

Any guess?
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Old 09-13-2008, 05:55 AM   #2
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Sounds like the clutch could be your problem.
Sometimes the clutch shoes dont release quick enough and stall teh motor or bog teh motor down

What springs are you using on the clutch ??

also doble checl all fuel and exhaust lines for any breaks or cracks.
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Old 09-13-2008, 06:04 AM   #3
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For some really good tuning advice, there is an entire thread on Go engines and their idiosyncrasies. It could be your clutch but it could very well be your HSN is too lean. I have one of these myself and it requires a different tuning method than any other engine I have ever owned. To summarize the thread (which I highly suggest you read anyway):

Start with the HSN 1/2 to 3/4 turn in from flush and the LSN 2 turns in from flush. Your idle gap NEEDS to be .7 to 1 mm. Get your engine up to temp and adjust your HSN until you get good, sustained high speed run with no bogging then turn your attention to the LSN. Unlike the other engines I own (or have owned) my best tune on the LSN is where it will take off from a 4 - 5 second idle as opposed to the normal 10 - 12 second idle. The pinch test should give you around 3 - 5 seconds before the engine quits.

Hope this helps but definitely give the Go engines thread a read.
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Old 09-13-2008, 06:33 AM   #4
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razzor:

I am using 1.0 clucth springs which i have been using since i started running this motor.

rstnboy:
My temps are good. I i have not changed my idle needle setting since i started running this year. So i would assume that is good but i will check.

I always have the bog, the only way i do not have a bog is when i am i high RPM high speed parts of the track, in the slow, lower RPM parts of the track is when i have the bog.
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Old 09-13-2008, 06:48 AM   #5
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I forgot to add that the tuning should be done with a half empty fuel tank.

Without actually being there to see and hear how your engine is running, I would definitely look at your clutch again. Check each shoe against the others for rebound strength and see if there is a weak spring. Are you running composite or alloy shoes? Alloy will usually give a bit better punch as they usually allow the motor to spool up a bit more before grabbing. This helps to alleviate some instances of a low bog.

If your clutch is all in order, try richening the HSN 1/8 turn at a time and see if it helps. It normally wouldn't make sense but the Go carb is a bit different beast.

Here is a link to some great info posted by MassiveMods on the subject. His post is about mid-way down the page. It helped me a lot when I first got my Go engine.

http://www.rctech.net/forum/nitro-of...hread-131.html
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Old 09-13-2008, 07:13 AM   #6
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What plugs are you using? I had that problem with a cold plug (going bad). Try running hot, O'donnel's 77 is a good start
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Old 09-13-2008, 07:27 AM   #7
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I have read most of that thread, but i will reread it. maybe i missed something.

I will always run a full tank through the motor and refeul run a lap or 2 before i start tuning.

i first went to the plug, i run 97T plugs.

I run carbon shoes
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Old 09-13-2008, 07:40 AM   #8
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I have the same engine and run the OS P3 which is a hot turbo plug. The 97T is a medium plug. Try changing to a P3 plug or the 77T which is a hot plug.
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Old 09-13-2008, 12:14 PM   #9
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Fat chance this is your problem, but its worth a shot;

I had the same problem with my brand new ws7 turbo l2g, I was running a JP-3. It'd run like a raped ape down the straightaways etc, but we have several jumps that are immediately after a tight bend, so you basically have to gun it form an idle on those jumps, and my motor would bog out everytime and i'd end up casing the jumps, flipping etc. Did some research and found out that the pipe I was running simply isnt the right pipe for the motor, so I went and bought an RB pipe and header best suited for my motor/track and the problem dissapeared. Didnt require any retuning or anything.
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Old 09-13-2008, 02:11 PM   #10
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what about this...i its actually a rich HSN? this is maybe why...it can ideal than take off with out bog. once cleared out it runs perfect, hence when i high speed, high RPM spots i am fine. When i get off the throttle in low RPM, Low speed spots it loads up and and acts as though its rich LSN needle bog.?

Just a thought...
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Old 09-14-2008, 09:17 AM   #11
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Default Bog

I change the Clutch springs after every weekend. I even carry an extra fly wheel for a quick clutch change at the track. But you say if the buggy sits for a few seconds it is fine, but if you coast you bogg down. It seems to me if the HSN was rich the opposit would be true. I have a tendency to make my HSN too lean, but the LSN a little too rich. I also normally run on short tight tracks, so that is my excuse. I would start by backing the HSN a quarter turn and see what happens. Run to open the buggy up then retune the HSN like normal. Slowly lean it out until you do not get any performance improvement then rich it up 1/16 of a turn. Then to get a good LSN do the old pinch test. Remember to be at full running temps. The pinch test will get u 80% there. Then you need to perform the idle test. You should listen closely. Idle the engine until it loads up and dies. 15 to 20 seconds is ideal. If it loads up early then dies you LSN is rich. If it starts to rev before it dies, then you are lean.

Good luck
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