not doing wheelies anymore

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savagechiken

savagechiken

Member
Messages
43
Location
BC, Canada
Well I finally finished my rebuild and the truck is not pulling wheelies like it used to. Do I need lower gearing? currently 17/47.....If not the gearing is it just my tuning? For example, how lean do I need to go?

Could my new heavier wheels/tires or exhaust pipe be the issue?

I have been driving it on grass and pavement, both of which are said to be excellant wheeling surfaces. It was very difficult to get it to wheely even after I tried to lean it out.
 
What other changes did you do on rebuild?
Yes wheel and tires could be it.
And yes tuning could be it also-too fat.
More info please.

Dave
 
Well the main change I guess would be going from an F4.6 w/plastic pipe to the K4.6 w/polished pipe. Gearing has always been 17/47 before and after rebuild except I switched to the vented 17t clutch. Changed from stock GT2 tires w/warlock rims to the maximizers w/zombies. I changed the grease in the diffs to heavy duty wheel bearing grease.

Too fat? please ellaborate.
 
Well then I would say that wheels and tires, gearing and diff would not be it.
I would tune the new motor leaner (in) a bit at a time with it fully warm and go from there.

Dave
 
Ok, good to hear that you think it is not my wheels, tires, or gearing. I will re-tune it next time I take it out. How lean are we talking here? and what temps?
 
Is it shifting? Your slipper might be loose and you are in 2nd gear.

I can wheelie with 17/47 and the HPI Goliath tires.

*
 
whipnet said:
Is it shifting? Your slipper might be loose and you are in 2nd gear.

I can wheelie with 17/47 and the HPI Goliath tires.

*
Click to expand...

I think you might be on to something because last time I ran it was shifting into second so early that I could barely hear it shift. I just assumed it was because I was on grass. Luckily there was no damage to the spur gear and I didn't know that a loose slipper clutch makes the truck run in second. Shifting too early into sencond might explain why I was getting bogged down off the line, even though I was tuned lean.

I will definately tighten up the slipper clutch before the next run.
 
Yep, sounds like your slipper has loosened a bit.

I tighten mine all the way down and back off 1/8 turn instead of 1/4. Some don't back off at all. Your call.

*
 
Ok, I tightened the slipper and did not make much difference so I tried tuning it and had a very hard time improving my off the line power, it just kept bogging down too much or going too lean. Got a couple wheelies but not consistently, I could not find a happy spot.

So I am thinking that it might be my fuel line length. During the rebuild I shortened it to the most direct line between the head and shock tower. Could the shorter line be pushing the fuel into the carb faster at a greater pressure? thus bogging it off the line? I do have an inline filter installed as well.
 
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I don't think that would be the case there dude. There has to be something else that we are not seeing.
You should find or at least get close to a happy spot-I still think it's a tuning issue.
Hopefully other members will help.

Dave
 
A few things that I have caused me loss of performance from a standing start include, but are not limited to:

- Exhaust: make sure this is seated correctly, is the rubber seal attached tightly around the manifold and your new exhaust using zip ties? try and push your manifold and exhaust pipes together then using new zip ties tighten them up so you get no pressure loss. is the manifold rubber gasket ripped or worn? Maybe try putting your old exhaust back on, then this will rule this one out.

- Fuel/tubes: what fuel are you using? did you possibly leave the cap off your nitro fuel and allow air/moisture to enter the fuel? as nitro fuel is made up from alcohol as well as other things, it will absorb moisture (water) and cause a loss in performance. Might be worth buying 1L of fuel to test this. Or, I have heard that putting the fuel in the freezer will freeze any water in the fuel leaving the oil and alcohol untouched, then you could skim the water off the top. could your fuel tubes be damaged/cracked/split or crimped in places causing lack of pressure? is there any damage to your fuel tank, I have had major problems with the HPI tank with the primer. What is the condition of the lid seal. take the fuel line off the carb, and the pressure line off the exhaust and blow through the pressure line while pinching the fuel line is there a loss of pressure?

- batteries/ hump pack: might sound simple, but what is the condition of your batteries in your transmitter/ receiver? if they are low on power the servos might be struggling to open the carb fast enough, thus causing reduced performace.

I think the guys already covered the other things..

Good luck with fixing it, let us know how you get on =)
 
Also, remove that inline filter. I had a problem simalar to this when I used one. That is if your fuel line will fit from your tank to your carb after your cut it shorter :duh:

You can pick it up pretty cheap from ebay or your LHS, and is always a good thing to have spare. I would try replacing this =)
 
How did the clutch look at the rebuild? Is it Alum? Sometimes matching a new CB with old clutch you lose your bite, due to the way it wore with the old CB.
 
Try putting the old pipe back on and see what happens. IF there is no difference you could have an air leak somewhere either in the fuel line or engine, could be the possible cause of bogging down off the line but appear to run lean.
Check the filter, it could be dirty.
I run Weld beadlocks with MOABS and have no trouble pulling wheelies at will.
 
Update! Good news is I got some wheelies today after re-tuning it and tightened the slipper clutch with no backing off. Also put more slack/length in the fuel line and put the shock screws in the highest hole on the shock tower. There was no signs of exhaust leak or anything. I think it will be a matter continuing to tune it in order to improve the wheelies. It can wheely but it takes some effort to do it. Not like some of these trucks I see wheeling without trying.

Bad news is I took it off a few jumps, trying to give it alot of gas in the air to try and flip and I shredded the spur gear eventually. Put a new spur on, tightened and backed about 1/8. Did some more jumps and then eventually shredded that spur gear as well. Giving it too much throttle while landing possibly? Was it too tight?
 
You really do not want to give it throttle on landings. Also, make sure your gear mesh is correct between your cb/sg. If its not set right it will either melt the spur if the mesh is to tight, or strip the gears if it is too loose. Oh yeah.. good to hear you got it running better
 
The mesh seemed fine, could it have just been the amount of throttle I was giving it at certain times such as right before landing?

What is perfect cb/sg mesh? How do I know I have it?
 
Personally I use the plastic bag the spur gear came in and put it between the cb and sg and mate them together, then line up the engine so the gears are inline and tighten engine down and remove the bag. Hold the CB steady and move the spur back and forth. there should be a little play between the two. This seems to work well for me.
 
When I hold the clutch bell, the spur only moves about 1mm back and forth and won't rotate anymore without slipping. Is this too tight?
 
What slips when you hold the clutch and move the spur because nothing should slip or even be close to slipping when doing this.
 
Edited:
Actually nevermind, it is not really slipping, the spur gets locks into the clutch bell and won't move a rotation if the clutch bell is held still.
 
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HMM... someone else may know if what a good measurement in for the mesh, but to me it sounds like 1mm play is too much, When the mesh is correct no matter how much pressure you put on it nothing should slip.
 
Took it out today after replacing the spur and tightening the cb/sg mesh. Did not notice much difference, got a couple wheelies. Then I go to start the truck and the engine is running, but the wheels are not moving. I can rev it up and spin the cb/sg, but no power is being transfered to the wheels. A couple of time it would do this for a few seconds and then all of a sudden the wheels would start to spin again. Now the wheels will not spin at all when the engine is running. What happened now? Clutch shoes? Transmission?

I did take the engine out to check out the shoes and they seem to be fine, but how can I be sure?

The transmission seems fine since I can still move the wheels by spinning the spur gear.

Perhaps the root of the wheely problem has emerged.
 
How much fuel do you have through this motor? Sounds like clutches not engaging. Could be worn clutchs, worn or a broken spring, or the inside of the clutch bell where the clutches engage could be dirty.
 
savagechiken said:
The transmission seems fine since I can still move the wheels by spinning the spur gear.
Click to expand...

If the motor is not running, you should not be able to spin the tires by turning the spur gear... not much anyway. Your mesh might be too tight or your clutches seized.

*
 
The engine has almost a gallon through it. When I turn the spur with the engine off I can move the tires a little bit at a time by turning the spur gear.

How do I know if my clutches seized?
 
If they were seized wouldn't it mean my wheels would be turning? Isn't my problem that its not engaging. I cannot see any damage on on the shoes.
 
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