RE: Problems when revving :( (Full Version)

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RE: Problems when revving :(

  

gerharddvs -> RE: Problems when revving :( (5/3/2008 2:06:36 PM)


I had a bike in the past that the sync was out.It made it lose a bit of power but not what this bike is doing.
I have noticed something else on my bike.When its cold it has no power.If I try and rev it above 2000rpm it wants to die.It doesnt smoke eather.As soon as its ran for a couple of minutes I can rev it Upto about 5000rpm but no more.The smoke then starts aswell. Its also recently starting to slightly backfire when U rev it.It idles fine but at about 3000rpm it sounds like its only running on 3 cylinders.I checked with a timing light and it is firing on all 4 cylinders.The sparkplugs dont look foild eather.
I'll see what I can do about a video but will be of my celphone so not good quality.I can them mail it to U or something.

  
Manic -> RE: Problems when revving :( (5/4/2008 10:40:12 AM)

Sounds like multiple problems.  Even if the carbs are out of sync, it shouldn't cause you that much problems.

First off, you have a '98, so you don't have a fuel pump.  You have a vaccum diaphram that will open up, and let fuel flow from the tank to the bowls.

Intially to me, from what you've said, it sounds like you have fuel starvation issues (it got better when you forced the fuel in).  Have a friend hold the tank off to the side, start the bike, then take some starting fluid, and spray it around the carb boots.  If your idle goes up, your boots aren't connected correctly, or they have cracks in them.

On the white smoke:  Have you check your radiator level lately?  If this hasn't changed, then it's probably just condensation building up, from starting and stopping the engine, without a real chance for the engine to warm up and "burn" off all that built up water.   Check your oil, does it have water in it?  Check all this first, before moving any further.

GL and post up what you find.

gerharddvs -> RE: Problems when revving :( (5/5/2008 7:51:41 AM)

Ok let me start from the beginning because it seems all the questions your asking I have actualy already checked...
I bought the bike as a project bike (It was put down on it's left side) but mainly just cosmetics. It was standing for quite a while (outside). The owner told me that he was driving it around in the yard the other day. When I got it I started it up but it was running very poorly like only three cylinders were firing. The problem is I never revved it for fear that the oil might be dirty. I then changed the plugs, drained the oil and cleaned the carbs. When I cleaned the carbs I didn't separate them cause that usually messes up your sync. I just took of the float bowls screwed out the jets and cleaned them with carb cleaner and compressed air.(Like I usually do when servicing a bike). I also cleaned the float valves and seats and put everything together again. I also unscrewed the pilot screws, taking notes how many turns the were out, cleaned them in the same manner as the other jets, and put them back unscrewing them 2.5 turns like they were. I did remove the diaphragm on the one carb and cleaned it but it was such a mission getting it back that I decided not to disassemble the other diaphragms (this one did look fine though). I did do a quick test to see if they were working by lifting them with my finger and letting them go. All of the slides go up if U suck on that diaphragm breather pipe. (not suggest doing this unless the gas is drained from the carbs cause U might get high). So the diaphragms seemed ok.
I reassembled everything and started the bike and thats when I started noticing all the problems. Running on 3 cylinders Power when cold. When hot slightly more power. I mentioned. I adjusted the pilet screws on the carbs to 1 turns cause the book specifies 1 turn and I even turnned them out to 3 turns but it doesn't make any difference. I gave up and left it sitting for a couple of weeks. Then over the weekend I gave it another try and thats when it suddenly started to make white smoke when it gets hot and when I noticed that it has more power when U blow into the breather pipe or the fuel hose. I couldn't have over heated it cause I never ran it hotter then about 60-70 degrees. I then took of the carbs again and checked all the stuff U guys suggested but didn't find anything. Keep in mind that I'm not a new bee and not completely ignorant when it comes to engines but this just baffles me.
I checked the coolant bottle and it's almost empty but the radiator is still full.
This is my theory. The top gasket is leaking coolant into the engine. The engine doesn't want to run when it's cold because of the coolant in mixing in the cylinder. As soon as the egine heats up most of the coolant can boil away or burn but so U have more power but since the water pressure increases it is pumping even more coolant through the gasket leak into the cylinder. When I blow through the pipe it's giving more gas to the mixture hence it can burn away more of the coolant.
To remove the gasket seems easy except that I think you have to drop the engine to do that, which is a major job. My tappet cover gasket is leaking oil so I'll have to replace it anyway but maybe without having to drop the engine. I need to find a conclusive test to see whether it is the gasket before I drop the engine and waste my time. Obviously U won't be able to set the carbs properly if the gasket is leaking.
Oh yes I forgot to mention that the spark plugs are burning very dark. Not foiled like with oil but dark like when the mixture is very rich. All 4 are the same shade but this isn't a very conclusive test since the bike haven't been driven like miles and miles running, only revved a couipoe of times in the garage. I don't want to start it many more times for fear of damaging something else Something else...the smoke smells very strange (maybe coolant) ...

Manic -> RE: Problems when revving :( (5/5/2008 10:43:44 AM)

Ahh, now we're getting somewhere.

Sounds like your on the right path.  I can't think of anything immediaetly to try and test if it is the gasket, other than doing a leak down test.

OR, with out actually having tried this, i am just brainstorming, pull the radiator cap, start the bike, and see if your getting pulses in the fluid.  Does that make sense?  I am thinking it will be tough to differentiate between the engine and the water pump.

gerharddvs -> RE: Problems when revving :( (5/5/2008 11:35:06 PM)

What worries me is that I never really revved the bike or drove it before I serviced it the first time so I wouldn't know if it was doing this when I got it and obviously I can't take the bike shops word that sold it to me. They're just trying to cover them selves.

I thinking of something now. In past I had a car tested at a radiator shop and they could determine in some way if the car was blowing gasses into the coolant. The car in question was loosing a lot of water and in some way they determined that the gasket was blown by doing some pressure test and putting some substance in the coolant. Maybe I should check with them if they can do the same test on a bike?

Manic -> RE: Problems when revving :( (5/6/2008 7:15:04 AM)

Good call, I've heard of that before, so I know what your talking about, but I've never experienced it first hand.  Give it a shot, if they can't do it, they might know someone who can.

mif_slim -> RE: Problems when revving :( (5/6/2008 4:47:49 PM)

I think they call that a leak down test. I did that with my BMW. You can buy it at autozone or something. Just put it into your engine or coolant and turn on the motor and wait for a little, then pull out the black light and check for a glowing color, if you see em, then its bad news, if not, its good news.

gerharddvs -> RE: Problems when revving :( (5/6/2008 11:59:56 PM)

This test sounds very cool and easy and I'd very much like to get more info on this substance but it's not a leakdown test.
I actually forgot that U can do a leakdown test and it can actually be used to diagnose a blown gasket.
A leakdown test is very similar to compression test. It is where you put the engine at TDC and pump compressed air into the cylinder via the spark plug whole with a leakdown tester. You then check if it's loosing any pressure on the gauges. What's so brilliant about this is that if it's loosing pressure, U can listen to hear where the air is leaking. If it's valves U will here the air coming by the exhaust or carbs and if it's gasket, it will blow bubbles in the radiator.If it's the rings U should get air coming out of the breather pipe. The only complicated part is to find TDC for each cylinder cause I think the one specified in the book is only for cylinder no.1

I found a site where they actually show U how to build one (I'm gonna try and build one)
http://www.motorcycleproject.com/motorcycle/text/leakdown.html

The thing is as with the compression test that it's very difficult to connect something to the spark plug holes on these bikes because it's so deep and so little space.

I'm still very interested in that substance of yours. Could U get me more info like what it's called then I can try and get hold of it.



Manic -> RE: Problems when revving :( (5/7/2008 5:32:20 AM)

quote:

ORIGINAL: gerharddvs
...I actually forgot that U can do a leakdown test and it can actually be used to diagnose a blown gasket.


Good thing I didn't mention that before...[:D]  cough, post #18.

gerharddvs -> RE: Problems when revving :( (5/7/2008 6:10:02 AM)

Yeah but I think I lost U after: "I can't think of anything immediately..." There wasn't suppose to be any good ideas after that phrase in the post:) (even more I was reading it from my cellphone)

Well it's still kind of a problem to get anything connected to the sparkplug holes on this bike but I'll take that guys advise and try and modify an old sparkplug.
Ironically I think it's probably cheaper to get someone to make you an attachment then to break a spark plug since they are so expensive...

Manic -> RE: Problems when revving :( (5/7/2008 10:15:03 AM)

lol, nice.

I think I'm going to make one of those testers.  Seems how I have some old POS champions that didn't want to run in the bike.

Yea, looking back on it, my post was very backwards.

GL on your test(s?), hopefully you find out something, that way you can move on to either fixing it or tyring to figure out the problem.

gerharddvs -> RE: Problems when revving :( (5/7/2008 1:17:53 PM)

I'd prefer to move on to actualy driving it :(
Does anyone know if U have to replace the headbolts when removing?

Manic -> RE: Problems when revving :( (5/7/2008 1:23:06 PM)

Do you have a shop manual, probably should say in there.  I'm at work, so I don't have my manual w/ me?  Check your PM

900FighterRR -> RE: Problems when revving :( (5/7/2008 6:20:16 PM)

When my supra had a blown HG my co-worker at the garage I worked at used the emissions tester off of the emissions mill to "sniff" the coolant.  If the coolant had any vapors associated with gas or oil they immiediately would register in its gas analyzer.  Thats a car though.  There isn't a simple way of checking this that I know of, I would assume your plugs would be wet though especially just after initial start-up and maybe a minute of running before the engine has time to get hot enough to evaporate the coolant completely.  I would contact the dealership and ask what their procedure of analisys is for determining HG integrity.  If you do pull the head I would definetely replace the bolts because they usually have a stretch factor designed into them when they are initially torqued and if your having an issue with the HG now then why risk it again down the road when a head bolt fails or loses torque.  Studs would be even better, call ARP Racing Fasteners.   However, you might want to rethink the engine all together because the previous owner may have run this thing for a while before giving up and parking it.  A blown HG leads to other problems quickly, especially on aluminum heads.  Hate to heap the depression on you but by the time you get new bolt, HG, and other misc. items associated with this job your looking in the 500$ range, and most used engine are under 800$.  Plus, like I said you are running the risk of more mechanical issues down the orad and it would be a crying shame to have a bearing spin or some shit after doing all the work on the top end.  You'll know when you pull the head.  Good luck man.

gerharddvs -> RE: Problems when revving :( (5/7/2008 11:41:29 PM)

Thanks for the manual I'll check it out (Manic)

Dude U have a point about the engine cause I got some quotes from Honda for the head gasket and the gasket on the tappet cover and that already is a lot of money.Don't even want to know what they'll charge me for head bolts.

The thing is if you bye an engine around here (South Africa) it's the same risk. You have to take some guys word that the engine has got low mileage and that it wasn't abused.Plus they want ridiculous prices for second hand engines and they don't give U any warranty. In this aspect I wish I lived in the states. You guys can just bye something of ebay. If I order something of ebay it will cost me more to get it here then to just bye it new in the first place. Most of the 2nd hand bike shops here just rip U off (there are one or two exceptions)

To get back to my engine. I'll first strip the head and have a look and also check the valve clearances etc. If I can fix it and the compression is fine after that, at least I know what I have cause if I get another 2nd hand engine I might have to go through the whole process again. I also think it will be a very good learning experience for future projects cause I can't afford to take it to a shop. I don't trust the bike mechanics around here anyway...

  

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