1996 DR-350SE (Tuning/Maintenance)

[BlitzkriegWulf]

Short background:

Uncle acquired this bike at some point in the early 2000's, and passed in 2005. Father inherited the bike, rode it for a month or so before it got stored in the back yard for 10 years under our deck. 2013-ish rolled around, and being young and wanting some fun, I pushed my parents to let me fix it up. rolling forward to 2015 the bike was rideable, and had low miles (3,350).

After a few good rides and getting the crap cleaned from the spark plug, cylinder, and doing 1-2 oil changes, the bike runs (more or less) flawlessly. Currently has ~4,600 miles.

Onto the questions:

When off the gas, there is always a loud, constant popping from the exhaust, louder and more frequent the higher the revs are. The bike has a Yoshi slip-on pipe, and I'm sure the db killer is long gone, if it ever had one. When fixing it up, there was a lot of gasoline in the oil, and the bike burned a ton of oil (Coated the inside of the exhaust tip black.. a lot of oil.). After all the oil burning in the cylinder went away, I changed the oil (Making sure it had good lubrication), rode the bike, and the issue seems to have fixed itself with week to week use and TLC.

I'd like to try and fix the issue, mostly to avoid pissing off the neighbors (or LEO's? Not sure if they care?) and just being able to feel good that everything is running as intended. I presume this has something to do with fueling and the carb likely needs adjusted? Any recommendations on places to get it tuned in or around Oakland?


After an exhaust has had so much oil run through it, 20 years of sitting/riding, and the bike is quite loud, is it worth re-packing the exhaust in an attempt to make it quieter?

Thanks for any advice/info/help!

 

[Lex Talionis]

Onto the questions:

When off the gas, there is always a loud, constant popping from the exhaust, louder and more frequent the higher the revs are. The bike has a Yoshi slip-on pipe, and I'm sure the db killer is long gone, if it ever had one.

I'm fairly certain your DR350 has the same type of carb my DR650 has, one that does not have a secondary circuit to meter in a bit of fuel under engine braking when the throttle has been closed. To my knowledge, all DRs have this "feature." Riders make fun of KLRs, however KLRs DO have this circuit and it works quite well, so long as the diaphragm for the circuit is in good condition; when the diaphragm in my old KLR's carb failed, it too would pop on decel. The loud aftermarket pipe accentuates this behavior. Nothing you can do other than not closing the throttle completely, maybe raising the idle rpm, or fattening the low-speed circuit so much you loose fuel economy. An OE muffler would greatly help.

I applaud your intent to quiet the bike.

Lex

 

[JimE]

If your looking to FIX the bike I have a Mikuni TM33 pumper carb, adapter, header pipe and stock muffler (might even have the modded one). Got those from Jesse Kientech before he retired. They are currently on a '90 DR350S but I think I just don't have time for that one as I have a '98 as well (with the magic button and a 440cc kit!). So anyways they are basically new parts if your interested PM me.

 

[JimE]

Actually looks like he's "semi retired". Call this guy he is super duper nice and knows everything there is about these.
http://www.kientech.com/

 

[Maddevill]

An air leak in the exhaust can make it pop on decel. Check around the flanges at the head. As far as the fuel, rebuild your petcock. It sound like it's leaking as is your primary valve in the carb. For sure repack the muffler. It's been oil soaked and the wrap in there isn't doing much any more.

 

[Sharky]

In addition to checking for exhaust leaks, perhaps a jetting change could help. My XRL stopped popping completely once I got the jetting squared away. My KTM pops like a MFer' and it's jetting feels great. You mileage may vary, but I support the aftermarket exhaust probably doesn't help.

 

[ScottRNelson]

My XRL stopped popping completely once I got the jetting squared away.

Mine pops like crazy under similar conditions to what the original poster has described. I just live with it. Throttle response is excellent everywhere. so if the only annoying thing it does is pop under deceleration, I can live with that.

 

[Sharky]

Mine pops like crazy under similar conditions to what the original poster has described. I just live with it. Throttle response is excellent everywhere. so if the only annoying thing it does is pop under deceleration, I can live with that.

I would take good throttle response over some popping any day. I barely notice it on my KTM anymore.

 

[BlitzkriegWulf]

If your looking to FIX the bike I have a Mikuni TM33 pumper carb, adapter, header pipe and stock muffler (might even have the modded one). Got those from Jesse Kientech before he retired. They are currently on a '90 DR350S but I think I just don't have time for that one as I have a '98 as well (with the magic button and a 440cc kit!). So anyways they are basically new parts if your interested PM me.

The bike isn't broken... Runs wonderfully, has great throttle response, and does everything it was designed to do. I'm not looking to make it a race bike, if I need more oomph (freeway for long periods) I'll just take another bike or the car.

The issue is two-part, the combination of overall noise and the popping. Even when I am wearing a helmet, I think the noise is borderline obnoxious. I can sit in the house and hear it coming from ~4 blocks away. I have a feeling that if I can quiet the bike any, that I can live with the popping.

Edit: I've heard a few DR-350's with the stock exhaust, and they're pretty quiet. I will try repacking the exhaust and see how big of a difference that makes.

An air leak in the exhaust can make it pop on decel. Check around the flanges at the head. As far as the fuel, rebuild your petcock. It sound like it's leaking as is your primary valve in the carb. For sure repack the muffler. It's been oil soaked and the wrap in there isn't doing much any more.

Thanks for the advice

To my knowledge, all DRs have this "feature."... The loud aftermarket pipe accentuates this behavior...

I applaud your intent to quiet the bike.
Lex

I wasn't aware it was normal (I've heard a lot of bikes and ridden a handful, none ever pop as much as the DR). Knowing that it's normal makes me feel better.

As for quieting the bike... If it's loud enough to grab the attention of the people around me, that's OK, if they can't see me, hopefully they can hear me. If I'm waking up/annoying the entire neighborhood and the surrounding blocks, it's too loud, and needs to be taken down a notch (I ride to have fun(respectful of my surroundings!), not to get on the neighborhood shit-list! ).

Mine pops like crazy under similar conditions to what the original poster has described. I just live with it. Throttle response is excellent everywhere. so if the only annoying thing it does is pop under deceleration, I can live with that.

If the popping is just the nature of the motorcycle, I can live with it. Hopefully re-packing the exhaust will help with the noise.

 

[ScottRNelson]

If the popping is just the nature of the motorcycle, I can live with it. Hopefully re-packing the exhaust will help with the noise.

I was referring to my XR650L in that post, in response to somebody else mentioning theirs.

Just in case you're interested, my fuel injected KTM 990 Adventure pops on deceleration too, but since it has the full original exhaust, you can barely hear it. Back pressure and better mufflers get rid of most popping noise.