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bike won't start

12K views 145 replies 24 participants last post by  jojje1963 
#1 ·
I need ideads. I got it back together after the valve adjustment and the parts i needed came in. But now it will not start at all. It turns and the battery is srtong, but it will not even fire a single time. Both sides have spark, tho i can't tell if they're weak or strong because it's been decades since i've checked for spark. Tried the old plug wires and no go. The igniter is plugged in as is everything i can think of. Plenty of gas, and i opened the cap to make sure it isn't vaccumed. Everything is as it was before i did the valve job. The cams are in correctly, i'm sure of that. Intake is the cam with the groove in it and the marks line up.....inlet cam=2 dots lined up w/drive gear, exaust cam the same but 2 slash marks. "top" displayed at top of drive gear. So i know they're in right. Checked the fuses too. And all vaccum lines and everything imaginable has been check to assure it's all plugged in.

Any ideas why this thing won't fire at all?
 
#3 ·
I did that, and i'm not sure but i may have really f'd up big time. All the marks were right, but it seems they can be right but with the crank in the wrong postion. i think there are 3 places where the cam marks on the drive gear are correct but different positions of the crank. So i may have destroyed my valves. I also noted that the spark seems real weak, tho i'm not sure if thats just from cranking it over trying to start it many times. They looked weak at first but are now looking weaker. I wonder if i would have heard anything is the valves contacted the pistons. If they did i'm screwed and i'll end up scrapping the bike cheap cuz theres no way i'm tearing it down. I've been at it 8 hours and i'm about dead. God i wish i woulda never done this valve adjustment now. :(
 
#5 ·
Hate to be the bearer of bad news, but kinda sounds like you bent some valves now.
Quick way to check, if you have no compression, is lift the valve cover, and do a simple check on valve clearance again.

If any are significantly wider than your settings, they are bent, and cant't reseat. It is also possible to crack a piston in situations like this.

The cylinder should be removed to inspect the pistons....excellent opportunity to fish out that bass washer!

Even better opportunity to get a 904 kit, and maybe send the head out to British Customs for a little port work and some bigger valves.

All I trying to say, is if you can afford such a drastic loss, maybe you can afford to have a professionally done upgrade...

Rather than take such a substantial loss. Take the bike to a dealer or indie shop and get it fixed. You'll lose less money that way, than selling it for 1/3 to 1/4 it value if it were running. Then you'll still have the bike you like.
 
#6 ·
Check the markings first. If you didn't line up the alternator there is a big risk that the valves are bent. And even if the clearance is ok, and the compression, they might still be bent but since the stems are so thin they could still seat good, DON'T leave it at this, you must remove the valves and check them!

But I don't understand how you could get it wrong. If you didn't remove the camchain gear and made sure that the cam marks lined up before removing the cams you should be ok, unless you turned over the engine while the cams where out?
 
#9 ·
Dazco,
Use a compression gauge to determine if you have proper compression. If you have proper compression, check to see if the crank position sensor is delivering spark when it should. If not,......DON'T PANIC.
This is "old school" but try this. Remove the valve cover and spark plugs. Put a pencil or wooden dowel in the spark plug hole resting on the piston. Carfully rotate the engine and determine, by cam/valve/piston position which cylinder is at TDC. Use fifth gear, with the bike on the full stand or jack it up and rotate the back wheel. The pencil/dowel should be at its highest position when both valves are closed for the cylinder firing at TDC. This should give you a better idea if the mechanical parts are in sync. Now determine if the engine position sensor is delivering spark when it should.
If you hit valves just turning it over with the starter, you should have heard something. It may have even stopped the motor from turning over if out of spec enough. If you did hear something, remove the head and inspect for valve/ piston contact. If you determine things are really out of wack mechanically, then maybe remove the head and inspect for valve/piston contact before going any further.If there is,...remove the valve/valves in question and check them.
Bonnie compression is not that high and there is some relief cut into our piston tops. Hopefully all is OK. It might be a pain getting things synced up,...just try to look at it as a learning experience.
Tony



[ This message was edited by: Jimi_X on 2006-11-18 19:08 ]
 
#10 ·
rather than answer each one that replied, let me just explain the latest. I finally go it started. However i'm not quite sure what to think. By the way Jimi, i'm way ahead of ya on the pencil trick. I remember reading somewhere what i RECALL (coulda been wrong, but looks like i wasn't) was someone saying it should be at TDC. So i used the pencil trick and realize the cams still weren't right. The marks on the gears lined up and the "toop" marking on the drive gear was at the top. But as i said before, the crank could be in the wrong position. So i used the pencil trick and got the left cyl at TDC with the "top" on the drive gear up top. Then removed the cams and put them back right, again !

Now i figured my valves are now screwed, but the bike started. But it smeeled like the valves were burning and there was smoke. But the cam cover gasket is on wrong and oil is flowing out pretty badly. But the thing is, it didn't smell like oil burning i don't think, and thats why i wondered if the valves got bent. So anyways, i took it for a 3-4 mile ride and it runs perfect. So i don't know if i coulda bent the valves or not, and i won't be able to see if the smell WAS just oil or if it was the valves till i put the gasket on right and let the remaining oil burn off. By the way, i was right about the valves being responsibvle for that cyclic vibration.......it's gone.

So anyways, i'll have to start again tomorrow and get the cam gasket on right and see if the burning smell goes away after whats left of the oil burns off. The only thing that gives me hope is that i read an archived post by Dinqua at BA from long ago when he did his first valve adjustment. He did the same thing as me and also worried the valves got crunched. But he then realized the mistake and reinstalled the cams correctly and found there was no damage. So maybe on this bike the pistons don't contact them no matter how the cams are in. And i didn't hear or feel anything wierd when turning it over by hand when the cams first went back in or at any time. So i have hope. But i've also resigned myself to junking the bike if it comes to that. But again, it runs perfect,idles perfect, everything. So can someone tell me if thats possible even if i frucked my valves?
 
#12 ·
I sure hope you're right Kliff. But what about what jojje said.....

"If you didn't line up the alternator there is a big risk that the valves are bent. And even if the clearance is ok, and the compression, they might still be bent but since the stems are so thin they could still seat good"

I still can't help but worry. Thanks for the peace of mind tho.....you have no idea how badly i need some right now. In fact i just sitting here refreshing the page over and over anxiously awaiting thoughts on this.
 
#13 ·
Well, the valves can hit the pistons if the timing is wrong, no question about that. And it can run good with bent valves (mine had 220hp with 4 bent ex-valves) and if they are a little bent they will break sooner or later and then you will also damage the piston and the head. Trust me. (that doesn't mean you have to do anything, that part is up to you)
 
#15 ·
Oh, and to Kevin and Sweatmachine and anyone who wished me well, i really appriciate that very much. Your concern is admirable, and it shows you really know what i'm going thru. It ain't cancer, but it IS very depressing.
 
#17 ·
I did check a couple clearances and they were good. Not all of them tho. Jojje......wouldn't i have felt something or heard something if they made contact, especially turning over by hand? By the way, i don't understand how the valves could be bent and still seat properly. Can you explain that?

[ This message was edited by: dazco on 2006-11-18 20:18 ]
 
#18 ·
No, not if they only tuched a little, the valves bend real easy. I couldn't here anything from my bike until I saw a video of a run, then I could here it.

I'm sorry but the only way to make sure is to remove the head and valves. You may be fine, but who knows. If it was my bike I would take out the valves, even if I had to pay someone to do it. Isn't there anyone you know that could help you?

And if the clearence has changed there is no question what I would do

[ This message was edited by: jojje1963 on 2006-11-18 20:25 ]
 
#20 ·
Well, i could do it if i had to but i really don't have the time or patience, and that would be a long hard job for me. Tomorrow i'll check the clearances when i remove the cover to re-seat the gasket. and see if they've changed. By the way, is there any chance the 270 engine is different than the 360 as far as valve contact ?
 
#26 ·
They must be bent. I did turn the engine with the cams out. And i removed them and reinstalled them twice at different points. Each time the gear markings lined up and the word "top" on the drive gear was at the top, but the crank was in different positions. I didn't realize there are like 3 different positions on the crank that allow the marks on the gears to all line up. It wasn't till i realized i had to stick a pencil in the left cyl to get the marks lined up WITH that cyl at TDC. So the engine was turned over plenty with the cams in the wrong position. So when i sell it i'll let that be known, but at least whoever buys it will be able to ride it home.
 
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