Scooterguy Mount With Tanaka 47R Engine

[5-7HEAVEN]

The 460 engine in this picture has been removed, as well as expansion pipe and boost bottle. In its place is a new bone-stock GP460 engine, mounted upside down so the sparkplug faces the ground. My special "bonnet" is upside-down, so it needed a few holes for drainage.This new powerplant has an OEM clutch, but its 8000rpm clutch springs were replaced with lower rpm springs.

This new engine started instantly at WOT; I had to lift the bike's tail and hit the kill switch. Surprisingly, the throttle cable housing needed to be shortened 1/4" to run properly. Carb adjustment seemed okay. The test and tune was short, as the engine's power snapped the bike chain just as it started to climb the steep grassy hill. The repair was easy enough, but need to visit the LBS for a new chain.

This MB's "Achilles' heel" is its bike chain. I need to find a super-duty one that can withstand the power of its high-powered engine.

 

[5-7HEAVEN]

Chain Issues

The bike chain is STILL jumping off in 1st gear. I'm using 3rd thru 6th gear, which bypasses the chain jump issues. The repaired chain is still holding up, but a new one is in my backpack, just in case.

I rode my bike to work yesterday. No troubles, as long as I avoid 1st and 2nd gears. Third gear is pretty low to start off, so no biggie.

Engine runs well with stock muffler.There's less hp and rpm range, but enough power to spare. I've been avoiding the highway and riding the side streets, until most of the bugs can be worked out. Since I'm not winding out the engine, gas mileage has greatly improved. The biggest issue is a fine oil mist from the exhaust, which ends up on my shirt. Also carbon monoxide issues. I need to install exhaust hose from engine to rear axle to prevent carbon monoxide poisoning.

JMO, oil spray and breathing carbon monoxide are the biggest issues that need to be addressed.

 

[Hawaii_Ed]

Not at all related to the bike build, but Julie and I had the pleasure of watching football and discussing life over beer and wings with 5-7 heaven. Good times! Thank you for hanging out with us

 

[5-7HEAVEN]

Holy Moly!

LOL! Ed, thanks for the night out, man!

Good food, good company and UH beat LA TECH!

Oh, and your wife Julie looked nice last night, as did Chelsea and Jennifer and Rachel, lol.

 

[5-7HEAVEN]

I rode my bike to work today. No issues, even after not using it for 8 days. Not using 1st, 2nd and 8th gear prevented the chain jumping. I still need to address the problem. In the meantime, I'll adjust the derailleur stops to prevent me from shifting into those gears.

Rick seems to be using a HT muffler on his 460! Hmmmm, If that works for him, I'll probably try the HT expansion pipe and see how that works for my engine. I'm having fine oil splatter and carbon monoxide thrown my way. Need to fix that pronto!

My friend Rick bought my 460 engine and installed it onto his Specialized. Can't wait to see it running. Maybe Hawaii Ed, Rick and I can cruise thru Waikiki. That's about 10 miles from our location. Maybe to Sandy Beach, which is 20 miles east.

Now all three of us have the power and acceleration to ride safely in Honolulu!

 

[5-7HEAVEN]

Hawaii Ed and my friend Rick dropped in on their motorized bikes. Unfortunately, Ed's MB conked out before he reached my place, so he stuck his bike in my van and drove to Stadium McD's. Rick and I mounted up and motored there, which is less than a mile downhill from my place.

It's amazing how well-mannered and quiet Rick's GP460 engine behaves, especially with the Happy Time stock muffler. My 460 engine is box-stock, but is much louder than Rick's. In fact, at the traffic light, I asked him if his engine was running (it was.).His 460 idles like my 2.2hp Mitsubishi engine, but with twice as much hp. On the way back to my place, Rick and I buzzed up the hill side-by-side, at about 30mph. He runs a Staton gearbox with NuVinci hub. I have shift kit with 2nd thru 7th gear cassette. My chain never jumped, so blocking out 1st and 8th gear was a good solution.

In search for more hp, I loaned Rick my 460 Dominator expansion pipe. If he can make it fit, I'll sell it to him.

Rick's setup looks good. He's running a 1.5 liter HT fuel tank, connected to a Walbro carb. Rick's not running his fuel-return line. I'm installing a 4-liter HT tank, so I just might plug my fuel-return line like Rick did.

Rick likes my upside-down 460 engine. Too bad we forgot to take pictures!

We'll run again when Hawaii Ed's bike is fixed. Orange Brian(from the other MB site) lives less than a quarter-mile away. This high-school kid has a Happy Time setup. Maybe he can join us next time.

 

[5-7HEAVEN]

I rode my bike to work today, a 5-mile run.

I noticed feeling dizzy on the days I use my MB to commute to work.

I have a hunch it's carbon monoxide poisoning. The stock muffler's short tip points forward, right below my head/helmut when I'm riding.

My son will bring the van to carry me and the bike home. No more riding until a solution is found.

Unsure if all MB's with Scooterguy engine mounts have this problem, if they don't extend the exhaust past the rider.

 

[5-7HEAVEN]

I ordered a SBP Happy Time expansion pipe for my GP460 engine. Although not specifically designed for the 460, it SHOULD work well for street use.

This pipe will allow me to add a tailpipe and extend the exhaust past the rear axle.

Boy, my headache lasted all day yesterday. I'm almost 64 years old, and can count the number of headaches I've had in my life on one hand. This was the worst; never had one that lasted all day.

 

[5-7HEAVEN]

The SBP pipe arrived yesterday, and I installed it today. Installation notes on the website helped a lot. Since my engine is upside-down, there's a lot of room for me to run the pipe ABOVE the engine. The expansion chamber itself does a 90-degree at the seat tube, then exhaust hose and SBP muffler attached to the chainstay.

The expansion chamber runs VERY close to my 18oz aluminum fuel bottle's cap. I can still pull the bottle out from the bottle cage holder. A 12oz aluminum fuel bottle will provide more clearance to the SBP expansion chamber.

The SBP pipe runs alongside, but below the bike's top tube. There's enough room for me to replace my 1.5 liter goped fuel tank with a Happy Time 4-liter tank.

I need to take my van into town for repairs. After a testrun, I'll stick the bike in the van, so I have a way to get home from the repair shop five miles away.

Pics to follow when my friend Hawaii Ed or Rick see my bike.

Time for test and tune!

 

[5-7HEAVEN]

This SBP pipe is THE BOMB! LOL.

Good fit, good price, good power, good looks, compared to my ADA S1 pipe, which looked like a shiny, chrome twisted party balloon on my engine. This one hugs the frame and engine, long and slim.

Test run up the grassy hill was the most powerful climb ever...and in 2nd gear, no less. I dropped off my van in town, then rode my MB home.

Engine's running super rich, spitting oil out the muffler. Need to lean out the carb. I also installed a new K&N air filter, so that might richen the engine.

Pics to follow when I meet up with Hawaii Ed and Rick.

Tonight I'll swap the 1.5 liter goped tank to a Happy Time 4-liter tank. The SBP pipe runs between engine and HT tank with great clearance.