Jama Laser exhaust on GS650G

[duaneage]

I swore I would never put a 4-1 on my bike. That was until I saw and heard a Marshall/Jama Laser exhaust. When all you ever see are MAC pipes then the product Jama makes warms your heart to the idea of aftermarket exhaust.

I acquired this exhaust for a very reasonable price and it was brand new. 4 separate pipes, new clamps, and a really nice muffler and collector. The collector is offset so the oil drain plug is accessible. Yes, you can design an exhaust with common sense. The 4 down pipes are equal length runs so the carbs see identical flow into the main pipe.

That gives a nice boost to the midrange torque and a sweet sound. I was actually surprised how quiet this pipe is. My only mistake was not measuring the old set first. The tone is definitely lower.





I replaced the dreaded exhaust bolts with a 13 dollar kit of studs from NAPA. Worth way more than that. It was so easy to mount the pipes and hang them from the studs. And they look great. I've had them on for about a year and no rust yet. There is a 5 mm hex head that you can hold the bolt still with while torquing them up. I used blue locktite on the threads to hold them in the head. And they look a lot better than bolts.

[duaneage]

There are numbers on each pipe corresponding to the cylinder. The two outboard cylinders go to the top and 2-3 go to the bottom. Another clever idea was to stage out the center pipes so the oil filter can come out. This pipe was designed by riders for sure. The clamps are very thick, almost 1/2" and are chrome plated for durability. The finish on the pipes is excellent and smooth.


I had to grind a few weld drips from the inside of a hole but overall great penetration on the welds.


The rear mount required a little tweaking for it to line up and it did not leave much in the way of adjustment. But it is a good 2 inches from the suspension and doesn't touch anything.



The center stand is retained, I didn't have to remove it for installation either. A heavy duty bracket has a hole drilled for the rubber fitting to prevent rattles. Another nice touch.

[duaneage]

I rejetted for this pipe for two reasons.

The 81 and newer bikes are famously lean jetted for emissions and fuel economy. Many riders report a single bump in jet size on the 650 and 750 engines improves performance. I took the bike from 110 to DJ 124 which is about 116 (or so I am told). The jets are close in size but the DJ 124 is slightly larger. I did NOT move the needles since I have the airbox and stock filter.

I think the 115 or 116 equivalent is the perfect match for this pipe. Perfect response off the line, really stronger midrange, and no miss or sputter all the way to redlne. I took the bike up an incredibly steep hill in 3 gear to 8500 and it pulled perfectly. No soot in the pipe at all.

[duaneage]

I synced the old pipe with the two inside cylinders lower than the outside, per recommendations in the manual. I was curious about the sync with the new pipe so I checked it. What I found was a surprise.

The carbs were equal across. The increased flow from the pipe on 2 and 3 appeared to equalize them out. I didn't have to adjust a thing. That has to be a first.

The same muffler is for the 550 and 650 engines



The 550 have smaller exhaust ports so you need specific downtubes.

[srsupertrap]

I have heard of that exhaust system so let's see a picture of it installed on your GS650G

[Charlie G]

Duaneage,

I'm really interested in this set up you have. Please post pictures and where you purchased the pipes. What are you doing with your stock set. I lost an exhaust sheild a few weeks, and ran over it. Bummed me, as my pipes are in pretty good shape. Been watching for a LH sheild on e-bay. Thanks for the information. I agree the 650 is all the bike you need.

Charlie G

[JTsGS650]

Can't wait to see the pics. How about a video so we can hear it?

[Charlie G]

Duaneage,

I'm hooked where's the pictures and other info?

Charlie G

[duaneage]

Can't wait to see the pics. How about a video so we can hear it?

Now there is an idea. It does have a nice sound to it. I need a shot of the "test hill" I use for jetting. Thats a good place to do both.

FWIW if you have a steep hill that's fairly long you can run up it in a medium gear and verify the main jet size. This is probably safer than triple digits on the freeway with a throttle chop. I ran mine up and killed the engine at the top. Coasted right to a stop and was able to get a reading.

The engine will draw max amounts of fuel on a steep climb. The load is the same as high speed into the wind.

So far no problems or blue on the pipes. I think I hit this just right. The midrange torque is very seductive, I find myself getting on it more now then I used to. The transition to full main power at 6K is very smooth still.

Buy this pipe if you can.

[Guest]

Buy this pipe if you can.

You didn't say where you bought it, or what you paid, but the Marshall/Jama/Laser Deeptones are quality pipes in Europe, and although still available for 80s bikes, are not cheap, esp. considering the cost of shipping to N. America. Might be slightly better now, with the current exchange rates due to the Greek fiasco though.

[duaneage]

You didn't say where you bought it, or what you paid,.......

Gentlemen's agreement.

These are rather rare items and although still available some people may be reluctant to take the plunge not knowing if they are worth the money, work properly, or even fit well.

I hope I was able to answer all three questions.

Coming soon: Audio!

[Charlie G]

Duaneage,

Your a tease.

[maro]

D's Pipe

Okay, I saw Duane's 4-1 this weekend. It's a stunner. Has an amazing growl and the bike lit up when I turned the throttle. WHAT!? I let him ride my 1100E so it's all good.