Another Cause of Rough Running Discovered and Shop Shout Out

[jas]

Thought I would share a bit of information on a 2004 Rockster (purchased new in 2006), 32,000 miles, that is ridden year round. Bike has a ztechnik exhaust system and carbon canister removed, other than that it is pretty much as it came out of the box. Bike maintained by me since 6K miles.

Recently my mileage started to suffer, idle was all over the place and the bike generally ran rough. The first thought was the dreaded stick coils, although after troubleshooting I could not single out a bad coil. Next I changed the plugs, spece’d the valves and completed a tbs (could get the throttle bodies close but not right on).

After much frustration I took the bike to a local independent mechanic (Mitch’s Motorcycles) in Boise. A few days later, I’m back on the bike and it runs like a champ. The primary issue was an air leak at the intake manifolds. The manifolds became warped over time and the o-ring did not seat properly. Evidently this happens over time, and the extreme hot and cold conditions that I ride in (sub freezing to 100+) do not help any.

Next, Mitch traded out the 1150R air intake tubes for the shorter and large diameter tubes from the S model. Which helps withairflow and honestly have made a difference, most noticable is the lack of exhaust popping when rolling off the throttle.

I cannot say enough good things about Mitch and for anyone in the area or traveling through, I highly recommend him for any work that needs completed. Mitch also sell and installs Ohlins (his site is Ohlinsforless.com). When I picked the bike up, I ordered a pair of height adjustable Ohins that are being spec’d and valved for the Rockster.

[boxermania]

jas

Excellent bit of information, along with the stick coils the manifold sealing has begun to show up now and again, specially as the bikes age. The S intake tubes will help you on the top end with a small torque loss at the bottom, the opposite occurs with the GS tubes (longer and smaller diameter) boosting torque dowm low at the xpense of top end. In any event the engine has so much torque (displacement) that any torque gain/loss is hardly noticed.

[sweatmark]

jas - great info! Wish I was just a bit closer for quick run over to Idaho and some fine tuning.

For the air intake: are you talking about the intake runner on left side of bike, that draws air into the airbox? Or do you mean the intakes connecting airbox to throttle bodies? If the latter, then that's the first I've heard of a swap for another oilhead's parts with aims of engine tuning.

Did Mitch replace the intake O-rings with new OE parts?

If you're interested, PM me with your info and I can send you some muffler packing material in appreciation for your info sharing. You're on your own for rivets... next time I repack the ZTechnik I'm going to use aluminum, after struggling with the stainless rivets.

Since Boxermania's in this thread - I've wondered if those of us with ZTechnik system (including y-pipe) might benefit from a slight increase in fuel pressure. Been thinking about trying an adjustable fuel pressure regulator to gauge engine reponse via inaccurate butt dyno... mostly looking for on-throttle smoothness/response, certainly not expecting any real HP increase at top end (who would use it on these bikes?)... IIRC Boxermania used a K-bike regulator within the OE fuel supply/return manifold, but I'm thinking about an external Bosch regulator and by necessity redoing the fuel lines.

[jas]

The air intake tubes I refered to are the intakes that connect the airbox to the throttle bodies, Mitch has done this mod to a few friends GS bikes with great results. With the Z - tek I gained on the low end and lost a little up high, if the increase in tube diameter does as Boxermania suggests (which I'm sure it does) then it might be back to normal? . The intake manifolds were warped as a whole and they both had to be replaced ($50 ea.).

Thanks for the offer of repacking material for the pipe, but I have an extra kit and rivets (I think we emailed back and forth for a bit about how to repack and rivet size).

[f4tweet]

I was told the RT tubes exchange make a big difference on the bottom end with an R1150R. Any input?

[riceburner]

jas - great info! Wish I was just a bit closer for quick run over to Idaho and some fine tuning.

For the air intake: are you talking about the intake runner on left side of bike, that draws air into the airbox? Or do you mean the intakes connecting airbox to throttle bodies? If the latter, then that's the first I've heard of a swap for another oilhead's parts with aims of engine tuning.

Did Mitch replace the intake O-rings with new OE parts?

If you're interested, PM me with your info and I can send you some muffler packing material in appreciation for your info sharing. You're on your own for rivets... next time I repack the ZTechnik I'm going to use aluminum, after struggling with the stainless rivets.

Since Boxermania's in this thread - I've wondered if those of us with ZTechnik system (including y-pipe) might benefit from a slight increase in fuel pressure. Been thinking about trying an adjustable fuel pressure regulator to gauge engine reponse via inaccurate butt dyno... mostly looking for on-throttle smoothness/response, certainly not expecting any real HP increase at top end (who would use it on these bikes?)... IIRC Boxermania used a K-bike regulator within the OE fuel supply/return manifold, but I'm thinking about an external Bosch regulator and by necessity redoing the fuel lines.

Some known mods I know of are :
R1150RT Manifold tubes
K1200LT fuel pressure regulator


errrr - poo, can't remember the rest (have more than likely mentioned them all on this forum in the past) - but I once saw a R1150GS with those two mods, and more, that was so friggin fast it could outrun my Rockster on sheer power, with TWO big burly blokes on it.