Shot in the dark here, but. The times that I have seen headpipes glow whether cars, bikes, or atv's, this was usually caused by a lean condition, wich could be from the carb or cam timming, and if it runs like a rapped ape then I say a lean condition from carb but it should back fire once in awhile when you gas on it. If it runs crappy compared to the way it should, then I would say cam timming. Usually when your plugs are about fouled they won't allow proper combustion and should'nt turn your pipes cherry red. When your pipes glow, it is usually caused from being too lean. They glow because your exaust temp is way out of the ballpark. Exaust temp should only be about 600 degrees I think. If you have a laser temp gun, shoot it and see where your exaust temp is. If your exaust is glowing then your plug should look like new, and maybe even some metallic on it. Cam overlap will also cause a vacume on the exaust and a tiny bit of pressure through the intake. Can you put air into the cylinder and confirm no air leaks through the valves. If there is air leaks then the leaking would have to be very very little. This info is only from my experiances so use it if needed. Good luck and I hope you get going. RUSS[img]i/expressions/face-icon-small-confused.gif[/img]

 

Ok, lets see what I can answer and provide more info with. I believe it's running way rich, it blows flames out the pipes a lot of times... won't rev worth a damn, you have to very gently feather the throttle to get it to rev at all.

When I set the cams, they were opposing each other, I could see the piston at TDC, and I had a TDC locking bolt in place, so I know they are right. It may very well possibly be the fouled plugs, I'll have to change them and see what I come up with.

It's got a charger hooked up to the battery so the cranking is strong, I can get it to run, but nothing seems consistant to tell any real true symptoms. I'll have to drop a few mains or something to get a base point to start from. It almost seems like the pressure coming from the intake is blowing the gas back out into the intake duct. When I did get it running, the vaccuum on the exhaust side was a lot less noticeable, I think it was just a lack of fire in the chamber therefore no explosion waiting to come out the exhaust, and it picked up on the intake stroke as the valves overlapped that bit.

I'll try some more things and get some more results.

Oh and about the headpipes, mine do usually glow, and sometimes pretty good. But they have never started to glow this fast before, nor this red. My fan turns on within minutes of running, which is very rare. But like I said I'll see what I can come up with here in a bits. Thanks for all the help and suggestions so far.

BTW how bad can head porting screwed up an engine? as in what symptoms can be created?

Thanks guys,
Devin

 

Well as far as porting goes I think porting would have to be massive to create a big loss in actual intake vaccume. I have never delt with dual over head cams yet so I can't say if the cams are right or not. Since I dont know what your engine modds are I also can't say if something can be done to correct your problem. I have built many performance and race engines though for street and drag racing so I can only offer suggestions without total answere's. But if it were me, I would deff put a new set of plugs in. By the way, headers should never glow, this is a sign of a engine being lean. The only time I have ever seen headers glow is when I had carb problems resulting in a lean condition or a cylinder not firing causing the unburnt gas to explode in the exaust. But this is only a 1 cylinder and if it does'nt fire then it does'nt run. I am not however saying that it is'nt running rich but it sounds lean to me. If it ran fine before the work was done then it should run fine now, but need the carb rejetted, and it should need bigger jetting if you are gonna make more hp. What color are your plugs if you pull them out after you let it run long enough for the header to glow? Have you considered the cdi malfunctioning? This would be my next test. Well I will check on this post tomorrow to see if you had any luck. RUSS

 

What now exactly does the decompression lever on the intake cam do? and what if I were to "creatively" remove it? what would happen then?

 

it would be harder for the starter to turn the motor over with the decomp lever removed. I see no benefit in removing it. Does it have free play? or is it stiff or stuck?

 

rfwill has A good point, Have you put an after market cdi on there while doing all these mod's?

 

I am back to running the stock CDI before thie porting and am still currently running it. My RWR seems to ahve crapped out. Can those be fixed btw?

As for the cam decompression lever, It's already gone....on 2 intake cams to top it off....Don't know how it happened, just snap and thats it. It seems to surn over just fine, although i did notice a drain on the battery a bit quicker. Other than that, as long as it's ground down evenly to maintain balance it should be fine shouldn't it?

Anyone ever run a stock exhaust cam instead of a stock intake cam? I might just have to do an experiment. stock intake opens at something like 15 degrees while the exhaust opens at 17 degrees. The intake closes at 45 and the the exhaust closes at 47. Numbers might not be relevent, but the relationship I believe is correct.

Oh well, back to the testing to see whats goin on.

 

*Omg! I cant believe i didnt catch this right off thê bat! Your decompressor should never be on thê intake side!!!

Stop, drop, and roll!!

You need to swap your câms ..... Thê decompressor is always on thê exaust cam. This is your problem.



Bigger.

 

Bigger.... you're seriously joking right? I can't believe I didn't catch on OMG. kinda funny now that you think about it. I have now broken 2 *ahem* exhaust cams, and all because of something that stupid of me to overlook. And to think of how many times I have been in there and torn apart that cam bridge, only to do this. Not once but again after something obviously wasn't right the first time.

Now everything makes sense. The timing seemed out of whack, vaccuum on the exhaust, compression on the intake, this all happening when the valves overlap.......well sh!tty.

So next question i guess here.....Does anyone have some cams they want to get rid of? I need 2 exhaust cams, either both stock, or a set of aftermarket cams, and a stock exhaust cam. Will it hurt anything to run with it like that in the mean time?

edit:the cam lobes did look like there was something a bit odd about them when they were opposing each other... they were both tilted downward a bit more than usual it seemed.....

and it makes sense. Why would you have a decompressor on an intake cam when during the intake stroke you want all the compression you can get?

DUH!
feel free to lugh at me, I'll be sulking in the corner.

 

dude, this **** is whack yo!