Question about my '90 vmax with supertrap exhaust

[SJohn33]

I bought a '90 Max in mid January primarily because it had a full supertrap exhaust on it and the owner was selling it with the original exhaust and a bunch of spare parts that I needed for my '92 Max. I've had it on the road a few times and it seems to be running on the rich side. I've read that the carbs need to be rejetted for the less restrictive exhaust but I don't know how to tell if it has been done or not. Is there a simple way to check that or do I need to tear into the carbs?

 

[Rollie]

I bought a '90 Max in mid January primarily because it had a full supertrap exhaust on it and the owner was selling it with the original exhaust and a bunch of spare parts that I needed for my '92 Max. I've had it on the road a few times and it seems to be running on the rich side. I've read that the carbs need to be rejetted for the less restrictive exhaust but I don't know how to tell if it has been done or not. Is there a simple way to check that or do I need to tear into the carbs?

Full supertrap exhaust ? Usually , to my knowledge , they are just slip-ons , not full ( header / mid-pipe ) exhaust system which does not require re-jetting. Carbs may need some work though . What is the rich symptom ?

 

[one2dmax]

i'd bet money it's jetted incorrectly. Either the stock jets are in there which are too big OR they have a stage one in there which is too rich too. Only way to know is to get the carbs off and check the main jet (needles can be checked by pulling a slide cover off with them still on the bike).

Sean

 

[SJohn33]

The full exhaust headers/mid-pipe and the exhaust are newer. I recieved the complete OEM exhaust including headers in a box with the bike. It's possible that the headers are new OEM but definately not the ones that had been on the bike originally. I'd include some pics here but I'm not sure how to do that.

 

[SJohn33]

Thanks, looks like I'll be pulling carbs! I should've responded that the primary symptom is that I smell raw fuel in the exhaust even after it's warmed up.

 

[naughtyG]

Thanks, looks like I'll be pulling carbs! I should've responded that the primary symptom is that I smell raw fuel in the exhaust even after it's warmed up.

That could also mean a sticky needle valve or even a rusty fuel tank! Not uncommon on an '90, do yourself a favor and take a good look with a flashlight inside the tank..

For pictures it's easy, two ways:

1- when you hit the reply button here, then hit the 'go advanced' button. You'll see a green icon with a paperclip - click on it to upload any pic from your 'puter

2- upload your pics to photobucket.com or similar, then use their links to paste directly into a forum message.

 

[SJohn33]

Thanks, I'll look in the tank and see what I can find in there. I've already done the basic maintenance type stuff; replaced fork oil, coolant and engine oil and filter and have new tires on the way for it. Here are the pics of the exhaust . The first one is of my Supertrap '90 and the second is my stock '92

 

[85vmax]

Looks like stock headers to me.
Check if the air fuel mixture screws have been drilled out...if they have they probably went into the carbs......has the bike been sitting?

 

[RaWarrior]

Agreed, the headers look to be stock. Quite possibly non-original ones, but none of the aftermarket ones have that chrome cover piece there to "blend" them into the stock muffler. I'm not sure Supertrapp made a full system? Their slip-on cans for the Max are pretty common though.

It should run OK with stock jetting and slip ons. You might drop them to a 147.5 (stock is 150) since they are a tad less restrictive than the stock muffler, but that wouldn't cause what you're describing.

In addition to what's already been mentioned you might check that all 4 choke plungers are working smoothly and not hanging up and that none of the forks are bent.

 

[naughtyG]

Can you take any pictures of the full exhaust on your '90, or at least the front headers as they come out of the front cylinders?

 

[SJohn33]

Over the weekend I pulled both bikes out and was able to get a good look at the headers and they are the same, just newer. So they must be the slip ons as everyone has indicated.

 

[NHSteve]

I have an 85 with full supertrapps as well "with no discs or end caps". Loud as hell and sounds great like a dragster! pics in my album...
Assuming it did did not need, and was not rejetted for the trapps.

Can I put on 6-8 discs and a closed end cap and not rejet???

I understand it would be adviseable to do so anyway. and i plan on having the carbs sync done as well.

thanks

 

[DMAN999]

Steve,
I have 8 Disks/Closed End Caps per side and Stock Jetting on my 2000.
The other option would be 2 Disks and Open End Caps with Stock Jetting.

 

[NHSteve]

thx - i think i will put the disc's and caps on this friday then....

"The other option would be 2 Disks and Open End Caps witrh Stock Jetting."

I would have to buy the open end caps. does this make it louder or more quiet?

 

[DMAN999]

Open End Caps are louder than Closed End Caps.

 

[NHSteve]

ok, well it is really loud already......a little quieter wont hurt.

thx

 

[08brute]

Why is it not good to have open supertraps? Not enough backpressure? Power loss?

Just curious because my 02 V has this setup with no disks or end caps.

 

[vmax2extreme]

Steve,
I have 8 Disks/Closed End Caps per side and Stock Jetting on my 2000.
The other option would be 2 Disks and Open End Caps with Stock Jetting.

I can vouch for these setups since I have run them both. Currently on my '05, I have the open endcaps with 2 discs. Both setups are equals for configuring. You shouldnt need to rejet with this setup. I run perfect with my setup.

 

[vmax2extreme]

Open End Caps are louder than Closed End Caps.

To be honest, I like open endcaps since the noise is behind you instead of besides you. Also with the closed endcap setup, you get carbon buildup on your bike since the exhaust blows out sideways.

Remember, unk:LOUD PIPES SAVE LIVES!!! unk:

 

[vmax2extreme]

ok, well it is really loud already......a little quieter wont hurt.

thx

How old are the supertrapps? If they are unbearably loud, you might want to consider repacking them. That might possibly quiet them up some too!