No Power 5th Gear

[kyriakos]

New RPS Hawk 250; but lacks power at top end. I've been reading 60 mph top stock, but I couldn't get it above 42. I rejetted the stock carb to 115, opened air box a bit, set the mixture at 1.5 turns out, set valve lash to .002, and was able to get top to 45-46 on flat ground. I thought it may be speedometer, but GPS confirms my speed at ~46.

Two sprockets arrived today and it feels good in lower gears, but I can't get any speed out of 5th gear... bogs out. My goal is a pretty simple 60-65 top speed highway, 55 cruising. Based on everything I've read, I should be there, but it's struggling. Any ideas?

I'm in Georgia, at sea level, temp ~70.

[JerryHawk250]

Are you still running stock exhaust? If so a 115 may be too rich. Is it bogging or cutting out on top end? If cutting out then it's too rich. To run a 115 jet you will need to remove the cat or go with a after market header pipe.

[Megadan]

A 115 main is too big without the cat removed or a different exhaust. Try a 110. Also, make sure your choke is not in the half position. That can do it too.

[kyriakos]

I'd consider it more bogging out, I get almost nothing out of 5th gear, and it will intermittently sputter if I hold full throttle.

I'll switch jet out to 110 tomorrow to give it a try, and recheck valves, maybe up those to .003/.004. Unfortunately, even before rejetting stock carb from 98, I had this same behavior, but maybe I've gone to the two opposite ends of spectrum.

I did confirm choke was open (took air intake off back of carb). With the air intake completely off, topping at 49. This is my first bike, is it normal for a battery to require charging every few days? I've got ~75 miles on it so far.

Appreciate the input; this has been driving me nuts for a few days!

[Megadan]

The stock battery is pretty mediocre in terms of quality. Almost all of us have swapped it out for a better one.

Something else worth noting. The stock spark plug is cheap and crappy, change it out. Also, check the ground points to the chassis. A poor ground can cause all sorts of issues, including weak spark or ignition. Ground wires are standard Honda green.

[JerryHawk250]

Definitely sounds rich. Like Megadan stated . Change out the crappy plug that comes with it to a NGK.

[blanc12]

I just put on the mikuni. I am stock at sea level. I am running a 110 and a 25. Runs like a champ. 60 is about all it will do but it runs great.

[kyriakos]

[forgot to mention] I am running the NGK Iridium.

The spark plug looked decent when I pulled it, although more brown than grey... I can't wait for 4pm so I can get home and recheck valve lash and flip in the 110 jet though. I also purchased the $99 exhaust system just in case it's something to do with exhaust.

This is likely a silly question, but where does the ground attach to chassis? I pulled fenders and headlight last night and nothing stuck out (almost every wire is green). Only thing left to pull is the fuel tank to to look under it.

[Megadan]

Only thing left to pull is the fuel tank to to look under it.

:tup:

[sshevie]

I do not know how many miles you have on your Hawk but these engines come very tight, for most people it seems it takes anywhere from 500 to 1000 miles to have it really broken in well and running to its full potential.

[Megadan]

I do not know how many miles you have on your Hawk but these engines come very tight, for most people it seems it takes anywhere from 500 to 1000 miles to have it really broken in well and running to its full potential.

Even my hawk could reach 55mph within the first 200 miles. I was hitting over 60 by 500.

I am personally leaning toeard 2 conditions adding up. Too rich main jet and the ignition is weak and cutting out under heavy load, aka wot in a high gear.

[kyriakos]

Unfortunately, similar after rejetting to 110. I upped my intake/exhaust lash to .003". Stripped paint under the ground wire. I do have ~100 miles on it at this point. With the 17/45 setup, I'd think it would do 60 easy, even @100 miles break in.

Exhaust system is slated to be here Friday, but I'll be surprised if that completely opens up another 20 mph. Recorded my GPS speedometer just a few minutes ago with audio, maybe that'll help?

https://youtu.be/QtNTK_rvo8s

[kyriakos]

+spark plug pics post-ride.

https://photos.app.goo.gl/yqOQeEZBEkXrOH5B3

[Cravin01]

Its definitely not rapping all the way out, Does the throttle lose all pick up in the last 1/4 turn or is it wide open?

If its wide open then you might need to re-adjust your throttle cable because you never got high in RPM's in any gear.

If its falling on its face at the top of the throttle then you need to look further into your jetting etc..

That bike should sing wide open but its not getting there.

[jimwildman]

Re: Exhaust system is slated to be here Friday, but I'll be surprised if that completely opens up another 20 mph.


Unless yers is all faulted up and clogged to chit! that will make it bog.

Personally I found that gear setup too tall, probly fine on flat roads, but I got lots of hills and wind to fight against.

id rather be able to get the revs up to hold speed and go a bit slower. 45 is pitiful tho :hmm:

[kyriakos]

Its definitely not rapping all the way out, Does the throttle lose all pick up in the last 1/4 turn or is it wide open?

If its wide open then you might need to re-adjust your throttle cable because you never got high in RPM's in any gear.

If its falling on its face at the top of the throttle then you need to look further into your jetting etc..

That bike should sing wide open but its not getting there.

Doesn't seem throttle does much past 25% of throttle, in really any gear. Similar behavior with needle shimmed and not shimmed. I tossed in the stock spark plug and removed gas cap for a run to ensure it isn't fuel ventilation, same behavior. Seems the 115 to 110 didn't really have much impact either. Maybe my stock carb is just busted... Mikuni VM26 looks like it's backordered by a month or so...

[JerryHawk250]

Did you visually check to see if the slide is fully open in the WOT position? Is there excess slack in the throttle cable?

[jimwildman]

Doesn't seem throttle does much past 25% of throttle, in really any gear. Similar behavior with needle shimmed and not shimmed. I tossed in the stock spark plug and removed gas cap for a run to ensure it isn't fuel ventilation, same behavior. Seems the 115 to 110 didn't really have much impact either. Maybe my stock carb is just busted... Mikuni VM26 looks like it's backordered by a month or so...

I remember clearing a bunch of casting clay out of the idle jet on the stock carb when I first got my hawk. the bowl had a bit in the corners as well. I had a time scraping it all out, I used a single bristle from wire brush to clear the jet. ran fine afterward.. worth looking into.

[kyriakos]

Did you visually check to see if the slide is fully open in the WOT position? Is there excess slack in the throttle cable?

I could blow through the jets. Throttle plunger opens and closes completely with no slack. Puzzles the crap out of me... On stock sprockets I couldn't get beyond 45, downhill... And I only weigh 160 :hmm:

[JerryHawk250]

I would do a compression test just to rule out if there's any issues with rings or leaking valves.

[kyriakos]

I would do a compression test just to rule out if there's any issues with rings or leaking valves.

Compression is @150. Not sure what's normal for these motors?

[Cravin01]

Im think that if it drops the ball after 1/4 throttle in any gear with different jets that possibly your pulling in air through a screwed gasket.

It may only happen after the engine develops more force (at a quarter turn) before it pulls in more air, it sounds unlikely on a new bike but possible.

I'm grasping at straws here! I would more than likely put the Makuni on it and double check all the seals around the carburetion system.

I can clearly hear that the bike wants to run, just be patient and go through the motions, you'll get it purring.

[kyriakos]

The good news (I think), on my way to the auto store to buy the compression tester, I got to 58 downhill :) It couldn't hold though, generally seemed to settle in around 49 straight, 45 or so uphill in 5th gear.

I may have to find that mikuni somewhere other than Amazon, 30 days backordered there.

[Ariel Red Hunter]

The good news (I think), on my way to the auto store to buy the compression tester, I got to 58 downhill :) It couldn't hold though, generally seemed to settle in around 49 straight, 45 or so uphill in 5th gear.

I may have to find that mikuni somewhere other than Amazon, 30 days backordered there.You couldn't have the rear chain adjusted too tight, could you?..ARH

[JerryHawk250]

Motor does sound weak in the video. I don't know if you were giving it full throttle. I think once you get the new exhaust on it and tune for that you will notice a difference. Also once you get some miles on it and broke in you will notice an improvement in speed.

[kyriakos]

Chain has some play, but I'll loosen it a little more for additional testing.

Video was with WoT through each gear. I've also found a Mikuni on ebay. Either way, I'll report back findings with whatever appears to make the difference.

150 lb compression sounds reasonable to me; but I don't know these engines to know if that proves/disproves valve/ring leak.

I definitely appreciate everyone's thoughts on it. As frustrating this is to someone stubborn like me, fun factor is already exceeding expectations!

[Megadan]

Personally I found that gear setup too tall, probly fine on flat roads, but I got lots of hills and wind to fight against.

id rather be able to get the revs up to hold speed and go a bit slower. 45 is pitiful tho :hmm:

I live in a very hilly (not small hills either) area well known for it's wind, and my bike is geared taller than his while carrying my much heavier body around, and I can hold 60mph all day long, with a head wind up a hill.

[timcosby]

that being full throttle it does sound weak like there is a restriction. check and make sure the air filter isnt soaked with oil as someone said it only holds a quart but manual says 1.6. if you had put in 1.6 it would of puked it into the air box and onto the filter which would restrict air. try running with out filter and you will know if thats it.

[Megadan]

My hawk holds 1.4 quarts to reach the center of the sight glass with the system completely drained. That means drain plug and filter screen cap removed and letting it sit to drain for several minutes.

[kyriakos]

I was able to put another 30 miles on tonight.

Checked air box, it's bone dry. Confirmed the intake from box to carb is also clear. Ran without the filter on, no difference.

I also ensured chain has a little play under load using a ratchet strap to simulate rider.

Also dropped a 120 main jet in, ran carb cleaner through all jets, everything seems clear for intake. The 120 jet didn't really have an effect either.

Have a multimeter, ground checks out across chassis.

Confirmed intake and exhaust valves are moving, holding that .003 lash on both.

I don't know if CDI or coil would have this effect, any way to check the output on these motors?

Really hoping exhaust is the issue, running slim on other thoughts... :hmm:

[Megadan]

Also dropped a 120 main jet in, ran carb cleaner through all jets, everything seems clear for intake. The 120 jet didn't really have an effect either.



This little detail right here catches my interest. That is a big jump in jet size. A 120 main on a Hawk with a stock exhaust system should be bogging out pretty badly, almost to the point of cutting out. That and taking the air filter off - aka open carb, also had no measurable or audible change - also odd.

The fact that there was zero change leads me to one of two conclusions, especially considering all of the testing, checking, and setup you just described.

The most likely conclusion in my mind is something is definitely wrong with the carb.

Either the bowl is barely getting any fuel to it - float level is too low or the valve is not opening fully, the Petcock isn't flowing enough due to some sort of blockage (not likely, but I won't discount it). If you have a fuel filter added to the fuel line, it may not be able to flow enough to keep up at wider throttle positions and is starving the bowl.

There is also the chance that you have a vacuum leak at the intake to head flange O-ring or Carb to intake O-ring. Or a poor seal at the throttle slide cap (also an O-ring seal).

The pictures of your spark plug (and the sound of your engine on the top end in the video) after that ride definitely back up something causing a lean condition. I would avoid pushing it hard for very long as you may cause damage to the piston and cylinder body.

If it were me, I would swap over to the Mikuni clone and call it a day. However, I would also check both O-ring seals on the intake for any sort of damage. It's not unheard of for the O-rings to be damaged during assembly at the factory.

Also make sure you don't over tighten the intake bolts to the head. Less than 20ft-lbs (about 15-18) is all they need. Too tight and the aluminum flange on the intake pipe can distort and actually cause a poor seal.

[lefty]

Please Forgive this inquery, Most of us have at least once had the Choke in the Wrong position. This happened to my this week!:doh: So is the lever all the way down? Is it functioning correctly?

Best, Lefty

2015 Hawk 250
2006 883 Sportster
1972 Honda CT70
Lost along the way;
1982 GS1100L
1983 Honda 185s 2ea.
1974 Puch 175mx
Right Arm

[kyriakos]

Please Forgive this inquery, Most of us have at least once had the Choke in the Wrong position. This happened to my this week!:doh: So is the lever all the way down? Is it functioning correctly?

Best, Lefty

2015 Hawk 250
2006 883 Sportster
1972 Honda CT70
Lost along the way;
1982 GS1100L
1983 Honda 185s 2ea.
1974 Puch 175mx
Right Arm

Yes, choke is functioning correctly, and down while riding. There was also an O-Ring at fuel sensor on bottom of gas tank that leaked, but has been replaced. I thought maybe a piece of that ended up clogging the petcock. A few days ago, I took off the petcock and ran carb cleaner through it, and the flow seems good. I had worked on a moped with a bad gas cap vent, so I ran without that cap on; but still no improvement.

I can't say there's no 'audible' sound when going WoT, I can hear the engine noise 'get deeper' between half and WoT, but no noticeable improvement in power. Makes sense that the sound would be air getting sucked without more fuel.

I'll pick up an O-Ring kit on way home and swap those out from carb and intake. The rings from factory on carb>intake and in the bowl seem to be stretched/tad too big.

Come on USPS, here's to the new carb/exhaust!

[JerryHawk250]

It wouldn't surprise me that once you replace the exhaust it will be a whole new animal. The cat could be plugged up just enough to rob it of power. It's probably something simple. Looks like you ruled out most of everything else.

[Weldangrind]

I've had two CG motors where the o-ring wouldn't seal where the intake tube meets the head. This caused a symptom where if you revved the engine, it would take several seconds to calm down to idle. On one of them, the o-ring was simply not inserted into the groove properly. On the other, the groove was cut too deep, resulting in no seal at all. I stacked two o-rings in the grove and called it a win.
None of this sounds like the symptoms you're seeing. I agree that the next step is the carb and exhaust.

[blanc12]

Is the throttle lifting the plunger all the way in the carb? Just a thought. Could be stuck or adjustment may be off.

[kyriakos]

Plunger confirmed to travel completely.

A slight update; my exhaust came in a day early. It sounds much more mean, but still no change in top speed on my quick test ride.

Hoping carb makes it tomorrow or Saturday. I can't wait to feel this beast, now that it's modded much more quickly than I had planned to do. Expecting a 15-20 mph jump when we knock out whatever this issue is!

[Its_not_a_honda]

Just thought I would show this. I am in the process of changing my carb and noticed this when reassembling. I have an Apollo 250. Different style engine than yours but you might want to check this. Intake gasket. One way perfect. The other way big blockage.

http://www.chinariders.net/picture.php?albumid=240&pictureid=1307http://www.chinariders.net/picture.php?albumid=240&pictureid=1308

[JerryHawk250]

Plunger confirmed to travel completely.

A slight update; my exhaust came in a day early. It sounds much more mean, but still no change in top speed on my quick test ride.

Hoping carb makes it tomorrow or Saturday. I can't wait to feel this beast, now that it's modded much more quickly than I had planned to do. Expecting a 15-20 mph jump when we knock out whatever this issue is!
Hopefully the new carb will resolve the issue.

[Megadan]

Yes, choke is functioning correctly, and down while riding.

Your choice of wording here interests me.

On the Stock Keihin style carb, the choke should be all the way UP while riding, with all the way down being fully engaged.

The Mikuni carbs work opposite of this, all the way down being choke off, and all the way up being engaged.

[JerryHawk250]

Your choice of wording here interests me.

On the Stock Keihin style carb, the choke should be all the way UP while riding, with all the way down being fully engaged.

The Mikuni carbs work opposite of this, all the way down being choke off, and all the way up being engaged.

On the stock PZ30 the chock is off all the way down. :)

[Megadan]

On the stock PZ30 the chock is off all the way down. :)

I actually had to go dig mine out of it's storage box to confirm lol. Been so long since I even looked at it that I forgot."

Never mind, ignore everything I just said.

[kyriakos]

Argh. New carb on, exact same behavior with power and speed. Maybe it is something electrical... Not sure where to start with that though...

[franque]

Did you check the intake to see if the gasket was partially blocking the port? I'd also do a leakdown test, too. You can swap CDIs pretty cheaply, maybe it's a bum CDI.

[Megadan]

I would like to change the line of thinking here and instead of focusing on top speed in 5th gear, maybe look at engine performance in other gears based on RPM.

Does the bike pull hard through the full RPM range in 2, 3 or 4? Does it feel like the engine falls off a bit in the higher RPM range when going through those gears too? It may be a little less pronounced because the load on the engine is lower, but it should be something you can still feel. The engine should pull nice and strong all the way to at least 7000-7500rpm.

I am still curious if you checked the O-rings on the intake pipe between it and the cylinder head. I would also look over the rubber on the intake pipe itself to make 100% sure there is no hole, tear, or crack that may be causing a vacuum leak. It's not unheard of even on a new bike.

Beyond that, assuming everything on the engine is good, then we need to look at other things that can be causing enough drag to slow the bike down.

Have you checked the rear wheel bearings? The 2017's seemed to have a problem with the factory installed bearings being installed poorly and were locked up and almost impossible to turn. My own bike had this issue.

How much slack is in the chain? If the chain is a bit too tight it will also cause some drag. I have found that to get proper chain tension on my Hawk, with the swing arm at full droop you need around 28mm (A bit more than 1 inch) of free play at the center of the chain - or 15mm with the suspension compressed until the chain is at it's tightest.

Have you checked the rear brake adjustment? It's not uncommon for some of these bikes to come with the rear brake adjustment just a hair too tight. This causes the rear brake to drag, which in the case of the Hawk is quite a lot of braking force since the rear brake is rather overpowered.

[kyriakos]

Did you check the intake to see if the gasket was partially blocking the port? I'd also do a leakdown test, too. You can swap CDIs pretty cheaply, maybe it's a bum CDI.

Intake is an O Ring on the Hawk. I did replace that with a new O Ring. I'll look into leakdown test. Never performed one of those, but Google never lets me down!

Does the bike pull hard through the full RPM range in 2, 3 or 4? Does it feel like the engine falls off a bit in the higher RPM range when going through those gears too? It may be a little less pronounced because the load on the engine is lower, but it should be something you can still feel. The engine should pull nice and strong all the way to at least 7000-7500rpm.

I thought it was pulling okay through 1-4, but I've also seen some folks mention possibility of a mini-wheelie... I don't feel there's enough power to hardly bring up the front shocks (much less wheelie) in any gear; I don't feel it's that strong. Though, I'm used to the power band of a 2 stroke, so I have very little to compare to, being my first 4 stroke bike.

I am still curious if you checked the O-rings on the intake pipe between it and the cylinder head. I would also look over the rubber on the intake pipe itself to make 100% sure there is no hole, tear, or crack that may be causing a vacuum leak. It's not unheard of even on a new bike.

I did change the O ring on the intake pipe and inspected that rubber on intake, all seemed okay. The stock O ring was a bit 'flatter' than I had hoped, the replacement was more pronounced.

Have you checked the rear wheel bearings? The 2017's seemed to have a problem with the factory installed bearings being installed poorly and were locked up and almost impossible to turn. My own bike had this issue.

I haven't done this, as the bike seemed to roll freely on ground and jacked up. I could certainly take these down and repack the grease, as I've seen that suggested on a fresh install. This was my plan medium term, but the missing power has been my primary focus before tidying and loctite-ing.

How much slack is in the chain? If the chain is a bit too tight it will also cause some drag. I have found that to get proper chain tension on my Hawk, with the swing arm at full droop you need around 28mm (A bit more than 1 inch) of free play at the center of the chain - or 15mm with the suspension compressed until the chain is at it's tightest.

I'll re-check.

Have you checked the rear brake adjustment? It's not uncommon for some of these bikes to come with the rear brake adjustment just a hair too tight. This causes the rear brake to drag, which in the case of the Hawk is quite a lot of braking force since the rear brake is rather overpowered.

I'll re-check.

My todo this evening:

Re-Check Chain Slack (1 inch sitting)
Re-Check Rear Brake Adjustment
Check Bearings / Repack Wheel
Leakdown Test


Note: I've also got a 27.5 pilot on order for the VM 26

If all checks out, I'll order a spare CDI. Should I stay stock on that, or is there a 'better' CDI out there?

[JerryHawk250]

:hmm: Very puzzling. Everything seems to be checking out okay that you have done. When you did he compression test, did you have the throttle in open position? I would do the leak down test. Have you tried a 115 main? May be loading up on fuel.

[kyriakos]

Throttle was fully open. Is 150 PSI within spec?

I've tried with the factory 98, 110, 115, and 120 mains. Behavior is very similar across the board.

I've gone ahead and ordered the All Balls Racing bearings, I'd rather those be quality anyway, and it's a good time to replace while the wheels are off. Has anyone replaced the coil/CDI with anything other than factory? Would it be worth going with a programmable CDI?

(At this point, I've swallowed the pill to replace the cheaper components to weed out potential issues.)

[JerryHawk250]

Compression should be around 175-180 psi. But being that the engine is new and rings have not had a chance to seat it could be lower. Even at 150 psi you should still have good bit of power.

[JerryHawk250]

FYI on the programmable CDI. It is a DC CDI and will require swapping of other electrical components to convert from AC to DC.

[Weldangrind]

I recommend a stock-style CDI for now. After you get the bike running properly (so as to set a benchmark), you can experiment with racing CDI's.

[timcosby]

might of been asked already but did you look into the end of the carb and move choke to see where open is? when i had oem 15/50 gearing i could do a wheelie in third gear but no it wont pull the wheel up by just twisting the throttle. you have a restriction or something bad with the electronics.

[kyriakos]

Just measured the Pickup/Exciter:

pickup - 180 ohm / .14 VAC
exciter - .023 ohm and slowly climbs over time held / 35 VAC

All of this seems low to the specs I've found, stator issue?

Forgot to mention; not sure what it is, but looks like some kind of oil has found its way into the wire harnesses.. Maybe they had the bike sideways and leaked oil over, then fried the stator?

https://photos.app.goo.gl/1R236zAozKeH79F13
https://photos.app.goo.gl/VppYueHKWsgtyuBt6
https://photos.app.goo.gl/DxjBVLsYg7wHEdzv9

[kyriakos]

https://photos.app.goo.gl/VppYueHKWsgtyuBt6
https://photos.app.goo.gl/Dwg8wR66qUWxPnCz1

https://photos.app.goo.gl/VppYueHKWsgtyuBt6
https://photos.app.goo.gl/Dwg8wR66qUWxPnCz1

[timcosby]

they may have put dielectric grease on the connections????

[kyriakos]

Budget Power Sports appears to be responding to warranty after threatening to stop payment... I've requested a new CDI, ignition coil, and stator.

I swapped back in the 15 front sprocket and loosened the chain, similar issue in no power around the 50 mph mark, and no particular 'bite' in any gears. New pilot jet arrives today, along with the wheel bearings. Also confirmed no drag on brakes, replaced brake fluids while I was at it.

[JerryHawk250]

Budget Power Sports appears to be responding to warranty after threatening to stop payment... I've requested a new CDI, ignition coil, and stator.

I swapped back in the 15 front sprocket and loosened the chain, similar issue in no power around the 50 mph mark, and no particular 'bite' in any gears. New pilot jet arrives today, along with the wheel bearings. Also confirmed no drag on brakes, replaced brake fluids while I was at it.
Hopefully it is just a bad CDI not advancing timing as it should. Funny how when it's your money they don't care but when it comes to there's it grabs there attention real quick.:)

[Cravin01]

I'm really surprised that you still have this issue with all that done so far, my bike easily climbs to 60 before it drains out the last few MPH. This bike should too.

[kyriakos]

A bit of an update. The company shipped out new coil, stator, and CDI. Made each of those changes (1 at a time), but the performance increased only a slight amount.

I've ordered a leakdown tester (can't find one around here for smaller plug threads). This thing is driving me batty, pretty much all that's left are ring/piston/cylinder/head internals, and rectifier. The rectifier seems alright though, battery voltage goes up within range while running...

I'm going crazy to get this thing resolved.

[JerryHawk250]

The leak-down test will let you know if there is an issue with the valves , cylinder or rings. If so, it sounds like a new parts or engine from the dealer.

[pistolclass]

wait I just thought of something, are you picking your feet off the ground when you are riding?
:hehe:

[kyriakos]

Looks like we've find the issue..

https://photos.app.goo.gl/fJnUAyHYXCJU0U8R2

[Shrug]

is that a horde symbol FOR THE HORDE

[Megadan]

Looks like we've find the issue..

https://photos.app.goo.gl/fJnUAyHYXCJU0U8R2

That definitely a good start. Where is the air going though? Coming out a port, or the crankcase?

[franque]

Yeah, I'm curious about that too... It shouldn't run at all with that much of a leak, unless one of the valves is open. Is that the lowest number that you get, when rotating the engine in the correct direction?

[blanc12]

Something is wrong with this leak down test If it has 150 psi in a compression test. A valve must be open or a leak in the line to the head maybe. Make sure it is on top dead center. It is just like adjusting the valves.

[franque]

Usually, what I do is slowly rotate the engine while cold at least two times with a breaker bar (since there's no ratcheting action), and whatever number is the lowest is your correct leakdown %. Then, you listen to where the air is escaping from, and then you have an idea of what is gone wrong. Just to double check, it's been verified that the clutch isn't slipping? Usually 10-12% is acceptable for leakage.

[franque]

Any updates?