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A couple questions about a new header installation

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Hey how's it goin!

 

I have a few questions that I was hoping someone may be able to help me out with. Today, I got my new exhaust which is a Big Gun Evo. I'm putting it on my TTR230 (the header was probably unnecessary, but I liked the bigger diameter pipe with the lower weight so I got it instead of just going with a slip-on).

 

Anyway, I couldn't find any torque specs for my particular bike...I checked the manual and did a Google search but found nothing. I figured that I'd just tighten the bolts until they were snug. Well, that was a bad idea, because I overtightened one of the bolts and it snapped!! Yup, so I was stuck trying to get that thing out for like 2 hours...Finally I was able to get it out with one of those reverse bit "EZ out" things and some vice grips. Ugh, what a pain...lesson learned!

 

So my questions are as follows:

 

1.) Does anyone know what the torque specs are for this particular bike? If it helps, the bolt size is a "M6 - 1.0 x 20mm". Google searches have told me anywhere from 8 ft-lb - 15 ft-lb, but I wanted to be certain before my dumb a** breaks another bolt (and I might not get so lucky the second time in being able to get it out)!

 

2.) Here is a picture of the header installed with the bolts tightened down (but not too much, and not yet to any specific torque:

 

Header%20into%20Block_zpsmyhz4jen.jpg

 

It seems like the header should be seated further into the engine block such that it is almost flush, but even with both bolts tightened down, it doesn't look right (as shown in pic). The metal plate shown here in the pic (I'm not sure what it's called) is the piece that came with the new header. Am I doing something wrong?

 

3.) I turned the bike on to see how it sounds, and it sounds pretty sweet. However, after only running the bike for 30 seconds tops, the header pipe gets EXTREMELY hot. Is this normal? Or is this a result of a now leaner running engine (I will not be taking it out to ride until I rejet the carb with the correct jets, but I just wanted to see how it sounded, so I fired her up real quick...and it got very hot, very FAST).

 

Any help would be greatly appreciated. Thanks a lot!

 

EDIT: My apologies if this is posted in the wrong section of the forum. There wasn't an 'exhaust section' in the dirt bike technical options.

Edited by Irishman301

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From that pic I'd say that on top of breaking the fastener, the over-tightening also deformed the 'plate' that holds the pipe to the exhaust flange.

Also I don't think that 'plate' should be flush with the cylinder, a gap is normal and probably keeps some spring tension on the fasteners

(perhaps even allows for metal expansion when the pipe gets hot)

 

If you want to save yourself some future headaches, coat those bolt threads with high temperature anti-seize paste,

that will lessen the chance they get stuck/rusted in there if ever you need to remove the pipe later on.

 

As for getting hot on idle, that would not likely be from lean jetting, I'm sure you revved it up a few time just to hear the pipe!

You will mostly feel it at higher rpms if that new exhaust requires richer jetting.

 

Just a tip, since you've managed to break this basic exhaust fastener,

be extra careful when you start taking your carburator apart and re-assembling it.

Jets are made of brass, carb of aluminium, a tad more than 'finger tight' is all it takes to put it back together properly.

 

Apart say from axle and steering stem nuts and a few suspension components

you"ll quickly notice that fasteners on a motorcycle require very little torque to tighten properly.

Edited by mlatour

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Hey thanks for the fast reply MLA!

 

Ya I feel like an idiot for snapping a bolt on such a seemingly simply task. However, in comparison to the 'feel' of the bolts that mount the muffler to the frame, I really didn't feel like I was tightening those bolts very much..IOW, I still felt like I had a ways to go before they were 'tight'. I was obviously wrong though. So now I basically just tightened the bolts until they were snug (it still feels like there's more room for tightening, but I don't wanna risk another breakage). In trying to move the header/muffler around by hand nothing moves around, so I'm assuming this means that it's properly secured (not sure if the bent plate is a problem. If so, I could always use the plate from the stock exhaust.

 

As for the leanness issue...even after running for only 15 seconds or so, there's some traces of smoke coming from the engine while it's running. Also, it misfires a lot while rolling back on the throttle...all signs of a lean running engine I think. I even called Big Gun before ordering this exhaust and asked them what jets were required, and they said that keeping the factory jetting is recommended.

 

Anyway, I have a #38 main and a #130 pilot jet, which are the jets that everyone on the forum recommends that has done any type of uncorking. Hopefully the rejetting and adjustment of the mixture screw will fix the running issues. And yes, I will be VERY careful when screwing in the the jets!

 

I'm a bit of a newbie to this kinda stuff, but I wanna learn to do all this on my own...It's half the reason that I got the bike in the first place.

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You should have ridden the bike around with the stock pipe first to get a feeling of how the engine runs when jetted properly,

then later on when you install the aftermarket pipe or do an airbox mod, you'll know right away where in the rpm range it feels lean.

Edited by mlatour

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I did run the bike stock. I took it out for 3 full days of riding before doing anything to it...

I agree with everyone's assessment of this bike being a bit too lean from the factory, because it does take FOREVER for the bike to warm-up enough to be able to ride with the choke all the way off...Apparently that's an indication of a lean mixture...or so I've read. So now with a much bigger and free-flowing exhaust, it makes sense that it is now even more lean. However, after it was warmed up the bike ran pretty well.

But ya, it's definitely not running like it was with the stock pipe on there even just at idle.

I'm gonna put it back together, and take it out for a 10 minute ride and then I'll pull the spark plug. Thatll give me a good analysis on how it's running.

Edited by Irishman301

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Remember that plug reading isn't very conclusive when using pump gasoline (either regular or premium)

as all sorts of additives and seasonal formulation changes skew the combustion deposits.

 

Race fuel on the other hand has consistent formulations making it easier to read plugs and fine tune the jetting,

especialy in 2 stroke engines where the lubrification is also dependent on the right fuel metering.

Needless to say race fuel isn't required in your TT-R nor would it improve it's performance.

 

Despite pump gasoline, your plug's colour can somewhat give you an idea what is generaly going on

but you will have to do some trial and error changes until the engine just feels right.

 

Posted often on Thumper Talk, here's a handy link on how to read plugs: http://www.braigasen.com/howtoread.htm

 

image002.jpg

Edited by mlatour

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Awesome thanks!

I think I'll be okay with getting the right mixture (I had dealt with the same thing with my old KZ440 bike, so I have at least some experience).

My main concern is the seal between the header pipe and the engine block. Is there supposed to be some kind of gasket there or is just a "snug fitting pipe" a good enough seal?

Edit: Nevermind...saw that they sell these gaskets on eBay, so I ordered one.

Edited by Irishman301

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When you replace the head pipe gasket remove the flange from the head pipe and beat it flat with a mallet, those ears bent from being over tightened.

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When you replace the head pipe gasket remove the flange from the head pipe and beat it flat with a mallet, those ears bent from being over tightened.

 

+1

or flatten it in a bench vise.

Edited by mlatour

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Thanks for the tip!

I think it's okay though. The bike is running nicely, no smoke (it was just a little bit yesterday, which I think may have just been dirt/gunk melting away). Other then a little bit of misfiring when revving the engine, which rejetting outta fix, everything seems good.

Also, I never saw any gasket in the first place, so I'm assuming it's still seated between the header pipe and the engine where it's supposed to be (it must've just stayed in there when I took the old pipe out).

Are there any indicators that I should look for that would tell me that it is or is not seated properly? I put my hand near it and don't feel any air leaking.

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Since you don't feel any air pressure leaking while the engine is running that's a good sign,

sometimes an exhaust leak sounds like a 'ticking' mis-adjusted valve, may happen either with the engine cold or up at operating temp.

 

After riding it for a while, look for any carbon build-up anywhere outside the pipe flange.

 

Don't be surprised if that shiny new pipe gets discoloured once the engine warms up a few time, that's quite normal.

Edited by mlatour

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Alright cool.

Ya there is a bit of an 'airy' sound during revving (again, which I was attributing to the lean jetting).

I'm just gonna take an extra precautionary step when the new gasket arrives and pop the pipe off one last time and see if the flange sits perfectly against the gasket. This way I'll know for sure if the over tightening caused any bending.

I guess it's dumb mistakes like this that causes the real learning ;).

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The header pipe will fit square in the head, and yes a new head pipe gasket is the smart route. With a pipe change jetting is needed, I re jetted after a pipe change. As far as the head pipe flange bending, pretty common..changing out header bolts is something I do when a pipe change is done or top end, always. What was the torque for factory nuts is not true for aftermarket.. You are talking steel VS aluminum flange , etc. Whatever Big Gun says is the spec. Hard to fathom the pipe didn't tighten down IF a gasket was in the head. Some pipes I doubled up the gasket, some gaskets crush readily so maybe yours was toast... Regardless that gets changed always in my book as the bolts do.

With regard to exhaust leak, spray soapy water from windex style sprayer right in front of the header to head mating. If blowing around the seal the spray will blow away.. Pretty easy. My opinion is you need a need gasket, if not 2 stacked.

Edited by Medic5150

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Cool thanks a lot for the tips!

I have a new gasket on the way, the carb is rejetted, and I put a 14T countershaft sprocket in. The new pipe sounds badass! This thing is gonna be fun once I have it all back together.

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