Topic: Trying to install Moto GP Werks exhaust on my 400F

[jcooper]

Hi guys!
Just got around to installing my new moto GP Werks pipe on my CB400F and noticed the frame loop that holds the old exhaust mount and center stand bump stop is totally in the way😱
I can mount the back half of the system so the can points almost straight out from the side of the bike.......or cut the loop off and mount it nice and flat against the frame.
I have spent a lot of time and reading watching a lot of you guys modify your bikes, de-tab your frames, and make some pretty irreversible changes, but it scares the ship out of me! I need someone to tell me this is not destroying a living thing, and that it will be alright!
Also.....when, if, I cut the loop off, that frame will be solid and still strong structurally?
Thanks!

[calj737]

Got a picture?

[innovativems]

Send a pic.  I believe you have to ditch the center stand with that one but it should clear the exhaust hanger.  Have you reached out to Chris?


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[calj737]

You do have to ditch the center stand with all the aftermarket 4:1 Yoshi style exhausts. But his mention of the bump stop and the hangar is what's confusing me...

[jcooper]

Hope these help explain. The frame loop has the center stand bump stop on bottom and the original exhaust bolts to this loop sa well. I have seen people with their exhaust at this angle, but it looks strange.
If I take the loop off I can rotate the pipe in tight to the frame and figure out a mount.

[calj737]

Yeah, that clears it up for me. I assume the exhaust bracket is welded to the loop? If so, removal is the only remedy I see. Do you think that will allow the tail pipe to orient to your satisfaction? Or are you still going to be in need of sawing off the peg loop?

[Retro Rocket]

Are my eyes deceiving me or is that rear peg mounted to the swingarm...?   If that loop is only there for the centre stand, cut it off, the pipe should be a lot closer to the bike, remember, these pipes were originally for race bikes, these are NOT a stock replacement....

[jcooper]

That loop only holds the exhaust and center stand bump and spring. The peg is welded right to the main frame.
I could just take the bottom flange off but I don't think it would give it enough clearance.
The other question is.......is this going to be crazy loud? I have a pipe on my 900...not this type but louder than stock, and my CBRs both have more open systems so I'm used to noise but this thing looks really open. I have heard YouTube videos and it sounds awesome.......but in person who knows.

[calj737]

It will be much louder than stock because it breathes that much better. You may be able to remove the baffle and wrap it more with matt to help reduce the volume if you find it too noticeable.

The reason I say "may" be able to withdraw it is on several I have had the rivets holding the name plate on obstructed the baffle from being pulled out. I actually drilled out the rivets, pulled the baffle and then installed new rivets.

[Retro Rocket]

That loop only holds the exhaust and center stand bump and spring. The peg is welded right to the main frame.
I could just take the bottom flange off but I don't think it would give it enough clearance.
The other question is.......is this going to be crazy loud? I have a pipe on my 900...not this type but louder than stock, and my CBRs both have more open systems so I'm used to noise but this thing looks really open. I have heard YouTube videos and it sounds awesome.......but in person who knows.

You'll have to remove that whole center stand loop to fit that pipe properly....

[jcooper]

I think your right.......going to have to remove the loop. This will be my first real frame surgery😷

[innovativems]

I think your right.......going to have to remove the loop. This will be my first real frame surgery

Take your time and you will be fine.  Only area that will be a pain of the bottom part where it's welded to the frame as the rear brake mount makes space alittle limited.  You got this!


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[calj737]

A 3" whizz wheel on an angle grinder works well. Install some band clamps around the tube to help act as a guide for cutting and to keep you straight and square with your cut.

[jcooper]

Thanks for all your help, suggestions!
Just thinking about a mount for the new pipe. There is a boss welded to the pipe and I was thinking of some kind of clamp on the frame and a aluminum bracket to boss. And clamp suggestions?

[jcooper]

Thanks cal

[calj737]

I used a spring looped around a bolt screwed into the boss on the tailpipe, then secured off my rearset bracket. Connected anywhere to your frame (not swingarm) would be fine and any method will work.

[Tim2005]

It looks like that's designed for the later type 400f frame with the higher pillion footrest loop. Have they sent you the wrong system? Early 400f was 75-76, later 76-78.

[innovativems]

I used a spring looped around a bolt screwed into the boss on the tailpipe, then secured off my rearset bracket. Connected anywhere to your frame (not swingarm) would be fine and any method will work.

Made me smile when you clarified not to mount the bracket to the swingarm.  Working on a buddies kz650 with a Mac system, guess where the bracket mount??? You guessed it, the lower shock mount on the swingarm!


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[jcooper]

Thanks cal....I will figure something out.

Not sure about the wrong pipe thing, but the guy at Motogpwerks said this was one of the last batches he was going to make....so I jumped on it. Just have to make it work.