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Discussion Starter #1
Hey all I did the scar mod yesterday went great bike starts right up on cold starts. Seems to be running great but my rear cylinder exaust pipe is still melting a cover. Do you think I'm still runing lean or is it a clearance issue I have about an inch of clearance from my cobra pipes to that cover. I'll post pics of the spark plugs and the cover. Also if I'm running lean would it start up cold or would it struggle
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Discussion Starter #4
Its showing no other signs of being lean other than the cover getting hot maybe I'm just paranoid I just dont know at this point
 

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The plugs look pretty lean (white) from the pic.......But if its starting good cold...I would think the pipe is too close to cover.
 

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How do you know that the cover damage is fresh and not left over from the previous hot pipes? Did you check the pipe surface temperature with an IR heat gun before and after the Scar mod?
 

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Discussion Starter #7
My pipe surface temp sits around 400 by that cover is that too hot ??
How do you know that the cover damage is fresh and not left over from the previous hot pipes? Did you check the pipe surface temperature with an IR heat gun before and after the Scar mod?
 

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With that much damage to the side cover. I would pickup 2 new exhaust gaskets, remove the exhaust, remove the old gaskets (make sure there aren't 2 sets in each), put new gaskets and retorque the exhaust on at 17 ftlbs. Also make sure that they didn't reuse the factor acorn nuts. If they did, pick up washers to put between the acorn nuts and the exhaust flange. It is likely that the acorn nuts bottomed out before actually applying 17 ftlbs to the exhaust gaskets causing a leak.

When I changed my exhaust, I replaced the factory acorn nuts with open ended nuts. No one can see the nuts anyways...
 

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400 F and an inch of clearance does not sound that hot to me. What is important is how much the temperature of the pipes dropped, if any, after you did the Scar mod. What was the pipe temperature before the Scar mod at the same location after the same amount of riding/warm up of the engine/pipes?
 

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Discussion Starter #11
400 F and an inch of clearance does not sound that hot to me. What is important is how much the temperature of the pipes dropped, if any, after you did the Scar mod. What was the pipe temperature before the Scar mod at the same location after the same amount of riding/warm up of the engine/pipes?
Unfortunately I was stupid and didn't check it. I just bought the bike the other day and it had been sitting for 3 years the cover was burnt when I bought it so there may not be a problem at all.i was just worried that 400 after a 10 minute ride was too hot I dont want to wreck the engine
 

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Unfortunately I was stupid and didn't check it. I just bought the bike the other day and it had been sitting for 3 years the cover was burnt when I bought it so there may not be a problem at all.i was just worried that 400 after a 10 minute ride was too hot I dont want to wreck the engine
Can you post a picture of the header nuts?
 

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I would start with removing those, and changing them to open ended nuts. Remove both on each header a little at a time, then put the open ended nuts on tightening each a little more at a time to 17 ft lbs. You wont have to remove the exhaust.

I could be wrong, but those look like the factory nuts, and I'm not sure I can see washers behind it. They may not be compressing the gasket enough because of this. This would let hot gasses escape.

Can you see any carbon (black soot) build up around the exhaust flange if you look under with a flashlight?
 

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Discussion Starter #15
I would start with removing those, and changing them to open ended nuts. Remove both on each header a little at a time, then put the open ended nuts on tightening each a little more at a time to 17 ft lbs. You wont have to remove the exhaust.

I could be wrong, but those look like the factory nuts, and I'm not sure I can see washers behind it. They may not be compressing the gasket enough because of this. This would let hot gasses escape.

Can you see any carbon (black soot) build up around the exhaust flange if you look under with a flashlight?
Yes it looks like there is a little build up on both of them I'll try this and report back thank you
 

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Yes it looks like there is a little build up on both of them I'll try this and report back thank you
If there is carbon, there is no doubt that hot gasses are escaping and the gasket isn't sealing.

I think it is an M8x1.25. I got my SS open nuts at home depot. Be very very careful... Those studs break... Maybe spray some liquid wrench around the nuts before you attempt to loosen them.

Be sure you are very careful putting the new nuts on 17 ft lbs, and work your way up to the 17 on each header.

Are you getting backfiring? This is also another sign of a bad header seal (you can still get it even with a good seal if you don't remove the pair valve).
 

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I went to Northwest/Ace hardware for some stainless steel metal lock nuts. I've used their lock washers before in conjunction with the acorn nuts. Maybe new hardware is in order. So you know for sure what's there and for how long.
Be careful in looking for those seals: they flatten out so thinly that it's hard to see them. A 90* pick helps.
Usually the rear plugs will look a little darker than the fronts - just the way air/fuel flows in the 1300. Yours are slightly too lean -- there's a spark plug illustration going from too lean to too rich in the 1300 stickys .. The plugs will always tell the tale on your tuning (as well as the butt dyno) (y)
Also, if you have any leaks around the exhaust gaskets, you will have backfiring when you let off the throttle.
Look at this: Spark Plugs
 

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Discussion Starter #18
If there is carbon, there is no doubt that hot gasses are escaping and the gasket isn't sealing.

I think it is an M8x1.25. I got my SS open nuts at home depot. Be very very careful... Those studs break... Maybe spray some liquid wrench around the nuts before you attempt to loosen them.

Be sure you are very careful putting the new nuts on 17 ft lbs, and work your way up to the 17 on each header.

Are you getting backfiring? This is also another sign of a bad header seal (you can still get it even with a good seal if you don't remove the pair valve).
I'm just getting a little pop on decel is all. I thought about doing the pair mad to see if it goes away because it doesent seem like I'm running lean based on bike performance. I just dont want to hurt the engine ya know
 

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I think replacing your exhaust nuts, and then removing the pair valve will help cure most of your problems.

I personally think you can't tell the leanness of your plugs from just removing them when you are finished riding. You have to remember you have a range of RPMs, you need to know how it is running at all RPMs to know Rich/Lean. Old school guys will go for a ride, kill the engine (coast to a stop on the side of the road) and check the condition of the plugs at different RPMs. If you bring the RPMs back down then check the plugs it is too late.

I took my bike and had it dyno tuned. The dyno has an exhaust sniffer, so he was able to look at the exhaust gasses at the full RPM range and go from there.
 
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