Tweet
I took my ’82 Maxim 1100 in for a tweek. I wanted a little more “umph” in the low to mid range. My local Kawasaki dealer, Bobby Pugh, is big time Legends car racer. He leads the nation in points this season for the Pro (road course) class of Legends cars. You can see the standings here if you’re so inclined.
Legends Race Standings
When I finally grasp what a Legends car was it dawned on me this guy would be a good choice to help me work on Zilla. He has a full blown shop with machining equipment for radius cut valve jobs, cylinder boring and milling of most parts.
Legends cars use the venerable Yamaha FJ1200 power plant. Bobby is a Legends dealer and he has rebuilt in XS of 1100 of these FJ1200 power plants over the last decade…seriously. So far this year he has built 97. I had never heard of Legends racing before I met him. Now I know it’s a big deal. A very affordable way to race.
Since Pugh had rebuilt so many Yammy air cooled I-4s and the FJ1200 is the offspring of the XS Eleven. I figured he had plenty of experience with the platform.
Through out this ordeal I have gained a great deal of respect for guys like Bobby and guys like our own Dan Hodges. Not only are these people bright but they have to be very tenacious to get the results they need to compete in a race environment.
So a couple months ago I brought Zilla into tweek the low end. Bobby Pugh slotted the intake sprockets and dialed the intake up 5 degrees. WOW! That made a significant difference. After that the torque curve was very well developed down low. Here’s the graph:
I brought the bike in after a long road trip. It was sick. Pugh put in on the dyno and it was only making 40 some hp. One of the carb diaphrams was pinched. He fixed that and dialed the intake up. As you can see Zilla made 72 hp and 54 ft-lb in stock condition with no mods. Not bad for the weakest of the Elevens…the Maxim. But the shift in the torque curve was awesome. I had hand fulls of it right off idle. If you need your torque down low I highly recommend this mod. You’ll have to slot the intake cam sprocket and advance it 5 degrees.
One other thing you should know just for reference. The Dynojet 1522 dynamometer that Stillwater Kawasaki employs was designed specifically for the1300 lb. Legends car. Though the cars use a motorcycle engine…they weigh a lot more than any bike. Due to the fact that rear wheel chassis type dynos compute horsepower from inertial forces this specific model of Dynojet is a little pessimistic regarding motorcycle RWHP. In general I think they’ve found that on most big street bikes the dyno rings up about 5 to 7 hp less than what one would normally see on something like a Dynojet 250. Given that Zilla’s stock hp would likely have registered in the high 70’s on a bike dyno.
This is really of no consequence because the dyno is most useful to mete changes in horsepower. The “big appendage syndrome” of absolute horsepower that has overtaken our sport is really nothing more than a pissing contest. So… If the slightly lower numbers of this experiment “bug” you then feel free to add an additional 5 (+-) hp to the figures. More than likely I will take the bike to another dealer and get a dyno run just for comparison. I spent this much…what’s another $100?
If you notice the maximal torque on the bike after the cam advance shifted to the 3500 – 5500 range. And upon riding the thing it was evident. If you look at bone stock Elevens…with no mods… most of them develop peak torque in the 6 – 7 k range. And they all demonstrate the typical dip in power and torque in the 4500 to 5000 range. As you can see in this graph that is not the case.
Shortly after this mod, I decided to get a little more radical. Since Zilla is a full dressed touring bike I really had no interest in building a “drag” machine. The objective of this rebuild project was to gain power and torque across the entire rev range but especially in the low to mid range rpm. A secondary issue was to increase gas mileage. Later I will tell you good news. We accomplished that task.
I had several 20 minute meetings with Bobby in his office. We discussed a plan of attack to rebuild the Eleven. I would gather up all the parts…bring the bike in and they’d go to work on it.
It took me about 3 weeks to get all the parts in. Last year I bought a 1981 cylinder block and head complete with cams for a whopping $50 on Ebay. I would use these as the basis of the rebuild. That way I could ride the bike while we bored the block and reworked the head. Another plus to using the ’80 block was getting rid of that damnable YIKES(yics) port.
The other prescribed parts were a Wiseco 1196 piston kit, a Web Stage II intake cam, and a Motad header. I had talked to several people about the Motad. Dan had sent me some info on the MAC Tri-Y system. It was a 4-2-1 setup and designed to take out the “dip” that is so prevalent around 5000 rpm. It cost quite a bit more but I figure it would be the ticket since a good 4-2-1 is designed for low end and mid range.
Boy did that turn out to be a disappointment. The Motad did not meet our expectations. More on this later.
Bobby cleaned the head up and installed new valve seals, and Kibblewhite springs. He re-cut the valve seats and did a 5 angle radius cut in the intake valves. I know nothing about building engines from the ground up. Apparently the idea for bottom and mid range it to get as much air into the engine as possible. The exhaust wasn’t open up much at all. Just the port face matched to the header flange. But on the intake he not only matched the ports to the intake boots but he removed enough material on all the intake ports to fill a 16 oz cup with shavings. I know…sat there and watched him with a die grinder thinking “Oh my gawd this guy ruining my pristine 1981 head!”. There was no polishing the head. Apparently this technique can actually hurt torque especially on the intake.
He also bored the block to match the pistons. Then he bead blasted the exterior of the head and block and painted the block with some high heat epoxy. It really looks good. Later I will sand and polish the fin edges for a nice little touch.
After Michael (one of Pugh’s mechanics) got it all put back together, we installed the Motad header and started it to make sure nothing serious was wrong. The bike sounded good so up on the dyno it went.
One other thing I didn’t mention. Bobby offered to try a set of his 36 mm Mikuni carbs off an FJ1200. I ask him if he thought they’d work and he said quite boldly with a big smile “…OH HELL YEAH!” I thought COOL…I’m game for anything.
The first couple runs are warm ups. But by the third run we knew something wasn’t right. Bobby had jetted the bike so that it should’ve been in the ball park for these mods and a 4-2-1 header. But the dyno runs were all very rich on the AF curve. So we pulled the door off the airbox and made a pass. Nothing changed. The run was still rich and the maxim only peaked at 68 hp.
Bobby loosened the clamp on the Motad and removed the muffler. WHAM! the dyno jumped to 72 hp but the AF was still rich. So I pulled the “Y” out and just let the exhaust flow through the 4 down pipes. The bike made 77 hp but was still rich…way rich…off the chart in spots.
Next we pulled the piece of BS (British Sterling) known as a Motad and installed the OEM exhaust. I thought this was a waste. But Mr. Pugh assured me the little Japanese guys in the white coats in Yokohama were very accomplished in what they did. We fired the bike up and made a pass. BINGO!!! The 1200 cc Maxim tipped the scale at 82 hp and the AF went lean mostly in the upper mid range. I started getting excited. I was having visions of grandeur. I began to hallucinate that we might install main jets with holes big enough to stick you fist through just to feed Godzilla the proper amount of food for the 300 hp we were about to experience as the mighty Maxim ripped the DynoJet from the moorings of the concrete floor!
Just then I snapped back to reality as I heard the bittersweet little nagging voice of a 110 lb female saying “I hope you can get a job here. You’re gonna have to do something to pay for ALL this!” I turned to see SWMBO walking straight to the dynamometer.
Have ya ever been in a garage full of dirty grease covered men when your wife walks in the door whining about her trip to Mazatlan going up in smoke out the tailpipe of your prized possession. I wanted to crawl under the drum of Dynojet and beg Bobby to make a quick run to get it over with.
After the tongue lashing we raised the needles on the 36mm Mikunis. Another run proved a slight increase of about half a pony and the AF was still lean. Michael had that dreaded look on his face that every mechanic gets when they have to pull carbs to re-jet. What he didn’t realize is how easy the Eleven is to remove it’s fuel distributors. He’d been working on those wretched crotch rocket Ninjas for years. You know the ones where the carbs are so tightly fit they look like they were melted and poured into the intake boots.
About an hour later we had it back together with larger mains. Again this run showed lean!!! Except this time we lost power. Now something was really up. Something that went far beyond the wading pool depth of my experience in a real garage. Mr. Pugh walked around to the back of the dynojet where the “sniffer” pump was. He removed a small threaded bottle with an air filter. It was plugged solid. Well so much for the past several runs. It was 6 pm. We called it a night and went home.
Next day with Godzilla facing east we continued our homage of bowing to the mighty Dyno…goddess power. Exhaust gas from the 1200cc mythical beast rose slowly upward like the incense of a burning alter. Then goddess Dyno revealed something we already knew. Zilla was rich. The plugged up air filter in the dynojet’s sniffer gave a bogus reading. Michael’s eyes rolled back in his head as he went for the tools to once again remove the FJ1200 carburetors from the mouth of Zilla. And once more he re-jetted to a more modest orifice size in hopes of getting the bike on target.
This time the dyno rang up 84 hp and we were almost there on the AF curve. So we put the door back on the airbox and started drilling holes. We drilled eight 1 inch holes in all and that didn’t do the trick…still rich. Then we took a die grinder and carefully excavated a hole in the back of the air box under the seat. As the AF got leaner we kept enlarging the hole until the Air Fuel ratio was right. Then we made one last needle adjustment to put it right on the money. The last run of that day registered 87.6 hp and 60.5 ft-lbs. Add the fact that the Dynojet 1522 is NOT designed for motorcycles and I think we can safely assume we are in the low to mid 90’s on rwhp at this point.
However when I test rode the bike the bottom was gone. We quickly figured out the idle jets were backed way out. Once those were set the bottom came back but was still a little mushy. So I asked Bobby to advance the intake back to the recommended dial. He had originally retarded the cam to help the bike build more top end. After he dialed it back to 108* we got a lot of the bottom and all of the mid back. We lost about 1hp on top.
This latest dyno shows the curves uncorrected. I personally printed it out today. The shop was jumping alive being it’s a Saturday and I hated to bother any of the employees to help me print it out. So I went to the Dyno Workstation and did the best I could. The scales look a little bogus and the graph is shy. The actual corrected numbers after dialing the cam forward were 86.4 hp and 60.4 ft-lbs. But you can at least see the base run of the Stock Zilla and the new 1200cc version.
Considering the fact we were stuck with the OEM exhaust I wasn’t too disappointed. We had gained 15.6 hp. That’s almost a 22% gain with no header. Now my only problem was finding a Supertrapp or Kerker. The reason I am bent on a Supertrapp or Kerker is because all the reading and research I’ve done talking to people like Dan Hodges indicates that Kerker/Supertrapp is the best choice for highly modified engines. Though the Motad would be a great choice for a replacement or minor mods (ie…re-jet and K&N) it simply wouldn’t flow enough to support 1200cc of fire breathing Japanese beast. The OEM pipes don’t do this motor justice either. So I’m just gonna have to take it on the chin and belly up to the table for a proven performer. $530! Ouch!
The good news is I found a Kerker yesterday. “The” Guru of XSives…the High Priest of Temple Eleven
in Kansas City…Bobby Jones…actually had a Kerker in his possession. It came off one of his personal bikes and he was willing to part with it. Apparently he’s rebuilding his bike to some new prototype called an SSR/2. I suppose you can go to www.merriamcycles.com and check it out if you are
so inclined.
The Kerker should be here mid-week. I will install it and strap Mr. Zilla back onto the Dynojet for a final tuning. Typically with a good header and re-jet you can expect to see 10 to 15% gain in peak power and a nice fat boost across the entire range. If that happens in this case (as it should) the Maxim will be ringing up something on the order of 95 and 65 ft-lbs of capital “T”. And if I take it to Tulsa or OKC to run it on a “motorcycle” dyno we might even see it drift into the magical realm of 100.
But I ain’t holding my breath! 
Don’t hold yours!
I’ll be updating this in a week or so.
CYA XSives
Legends Race Standings
When I finally grasp what a Legends car was it dawned on me this guy would be a good choice to help me work on Zilla. He has a full blown shop with machining equipment for radius cut valve jobs, cylinder boring and milling of most parts.
Legends cars use the venerable Yamaha FJ1200 power plant. Bobby is a Legends dealer and he has rebuilt in XS of 1100 of these FJ1200 power plants over the last decade…seriously. So far this year he has built 97. I had never heard of Legends racing before I met him. Now I know it’s a big deal. A very affordable way to race.
Since Pugh had rebuilt so many Yammy air cooled I-4s and the FJ1200 is the offspring of the XS Eleven. I figured he had plenty of experience with the platform.
Through out this ordeal I have gained a great deal of respect for guys like Bobby and guys like our own Dan Hodges. Not only are these people bright but they have to be very tenacious to get the results they need to compete in a race environment.
So a couple months ago I brought Zilla into tweek the low end. Bobby Pugh slotted the intake sprockets and dialed the intake up 5 degrees. WOW! That made a significant difference. After that the torque curve was very well developed down low. Here’s the graph:
I brought the bike in after a long road trip. It was sick. Pugh put in on the dyno and it was only making 40 some hp. One of the carb diaphrams was pinched. He fixed that and dialed the intake up. As you can see Zilla made 72 hp and 54 ft-lb in stock condition with no mods. Not bad for the weakest of the Elevens…the Maxim. But the shift in the torque curve was awesome. I had hand fulls of it right off idle. If you need your torque down low I highly recommend this mod. You’ll have to slot the intake cam sprocket and advance it 5 degrees.
One other thing you should know just for reference. The Dynojet 1522 dynamometer that Stillwater Kawasaki employs was designed specifically for the1300 lb. Legends car. Though the cars use a motorcycle engine…they weigh a lot more than any bike. Due to the fact that rear wheel chassis type dynos compute horsepower from inertial forces this specific model of Dynojet is a little pessimistic regarding motorcycle RWHP. In general I think they’ve found that on most big street bikes the dyno rings up about 5 to 7 hp less than what one would normally see on something like a Dynojet 250. Given that Zilla’s stock hp would likely have registered in the high 70’s on a bike dyno.
This is really of no consequence because the dyno is most useful to mete changes in horsepower. The “big appendage syndrome” of absolute horsepower that has overtaken our sport is really nothing more than a pissing contest. So… If the slightly lower numbers of this experiment “bug” you then feel free to add an additional 5 (+-) hp to the figures. More than likely I will take the bike to another dealer and get a dyno run just for comparison. I spent this much…what’s another $100?
If you notice the maximal torque on the bike after the cam advance shifted to the 3500 – 5500 range. And upon riding the thing it was evident. If you look at bone stock Elevens…with no mods… most of them develop peak torque in the 6 – 7 k range. And they all demonstrate the typical dip in power and torque in the 4500 to 5000 range. As you can see in this graph that is not the case.
Shortly after this mod, I decided to get a little more radical. Since Zilla is a full dressed touring bike I really had no interest in building a “drag” machine. The objective of this rebuild project was to gain power and torque across the entire rev range but especially in the low to mid range rpm. A secondary issue was to increase gas mileage. Later I will tell you good news. We accomplished that task.
I had several 20 minute meetings with Bobby in his office. We discussed a plan of attack to rebuild the Eleven. I would gather up all the parts…bring the bike in and they’d go to work on it.
It took me about 3 weeks to get all the parts in. Last year I bought a 1981 cylinder block and head complete with cams for a whopping $50 on Ebay. I would use these as the basis of the rebuild. That way I could ride the bike while we bored the block and reworked the head. Another plus to using the ’80 block was getting rid of that damnable YIKES(yics) port.
The other prescribed parts were a Wiseco 1196 piston kit, a Web Stage II intake cam, and a Motad header. I had talked to several people about the Motad. Dan had sent me some info on the MAC Tri-Y system. It was a 4-2-1 setup and designed to take out the “dip” that is so prevalent around 5000 rpm. It cost quite a bit more but I figure it would be the ticket since a good 4-2-1 is designed for low end and mid range.
Boy did that turn out to be a disappointment. The Motad did not meet our expectations. More on this later.
Bobby cleaned the head up and installed new valve seals, and Kibblewhite springs. He re-cut the valve seats and did a 5 angle radius cut in the intake valves. I know nothing about building engines from the ground up. Apparently the idea for bottom and mid range it to get as much air into the engine as possible. The exhaust wasn’t open up much at all. Just the port face matched to the header flange. But on the intake he not only matched the ports to the intake boots but he removed enough material on all the intake ports to fill a 16 oz cup with shavings. I know…sat there and watched him with a die grinder thinking “Oh my gawd this guy ruining my pristine 1981 head!”.
There was no polishing the head. Apparently this technique can actually hurt torque especially on the intake. He also bored the block to match the pistons. Then he bead blasted the exterior of the head and block and painted the block with some high heat epoxy. It really looks good. Later I will sand and polish the fin edges for a nice little touch.
After Michael (one of Pugh’s mechanics) got it all put back together, we installed the Motad header and started it to make sure nothing serious was wrong. The bike sounded good so up on the dyno it went.
One other thing I didn’t mention. Bobby offered to try a set of his 36 mm Mikuni carbs off an FJ1200. I ask him if he thought they’d work and he said quite boldly with a big smile “…OH HELL YEAH!” I thought COOL…I’m game for anything.
The first couple runs are warm ups. But by the third run we knew something wasn’t right. Bobby had jetted the bike so that it should’ve been in the ball park for these mods and a 4-2-1 header. But the dyno runs were all very rich on the AF curve. So we pulled the door off the airbox and made a pass. Nothing changed. The run was still rich and the maxim only peaked at 68 hp.
Bobby loosened the clamp on the Motad and removed the muffler. WHAM! the dyno jumped to 72 hp but the AF was still rich. So I pulled the “Y” out and just let the exhaust flow through the 4 down pipes. The bike made 77 hp but was still rich…way rich…off the chart in spots.
Next we pulled the piece of BS (British Sterling) known as a Motad and installed the OEM exhaust. I thought this was a waste. But Mr. Pugh assured me the little Japanese guys in the white coats in Yokohama were very accomplished in what they did. We fired the bike up and made a pass. BINGO!!! The 1200 cc Maxim tipped the scale at 82 hp and the AF went lean mostly in the upper mid range. I started getting excited. I was having visions of grandeur. I began to hallucinate that we might install main jets with holes big enough to stick you fist through just to feed Godzilla the proper amount of food for the 300 hp we were about to experience as the mighty Maxim ripped the DynoJet from the moorings of the concrete floor!
Just then I snapped back to reality as I heard the bittersweet little nagging voice of a 110 lb female saying “I hope you can get a job here. You’re gonna have to do something to pay for ALL this!” I turned to see SWMBO walking straight to the dynamometer.
Have ya ever been in a garage full of dirty grease covered men when your wife walks in the door whining about her trip to Mazatlan going up in smoke out the tailpipe of your prized possession. I wanted to crawl under the drum of Dynojet and beg Bobby to make a quick run to get it over with.
After the tongue lashing we raised the needles on the 36mm Mikunis. Another run proved a slight increase of about half a pony and the AF was still lean. Michael had that dreaded look on his face that every mechanic gets when they have to pull carbs to re-jet. What he didn’t realize is how easy the Eleven is to remove it’s fuel distributors. He’d been working on those wretched crotch rocket Ninjas for years. You know the ones where the carbs are so tightly fit they look like they were melted and poured into the intake boots.
About an hour later we had it back together with larger mains. Again this run showed lean!!! Except this time we lost power. Now something was really up. Something that went far beyond the wading pool depth of my experience in a real garage. Mr. Pugh walked around to the back of the dynojet where the “sniffer” pump was. He removed a small threaded bottle with an air filter. It was plugged solid. Well so much for the past several runs. It was 6 pm. We called it a night and went home.
Next day with Godzilla facing east we continued our homage of bowing to the mighty Dyno…goddess power. Exhaust gas from the 1200cc mythical beast rose slowly upward like the incense of a burning alter. Then goddess Dyno revealed something we already knew. Zilla was rich. The plugged up air filter in the dynojet’s sniffer gave a bogus reading. Michael’s eyes rolled back in his head as he went for the tools to once again remove the FJ1200 carburetors from the mouth of Zilla. And once more he re-jetted to a more modest orifice size in hopes of getting the bike on target.
This time the dyno rang up 84 hp and we were almost there on the AF curve. So we put the door back on the airbox and started drilling holes. We drilled eight 1 inch holes in all and that didn’t do the trick…still rich. Then we took a die grinder and carefully excavated a hole in the back of the air box under the seat. As the AF got leaner we kept enlarging the hole until the Air Fuel ratio was right. Then we made one last needle adjustment to put it right on the money. The last run of that day registered 87.6 hp and 60.5 ft-lbs. Add the fact that the Dynojet 1522 is NOT designed for motorcycles and I think we can safely assume we are in the low to mid 90’s on rwhp at this point.
However when I test rode the bike the bottom was gone. We quickly figured out the idle jets were backed way out. Once those were set the bottom came back but was still a little mushy. So I asked Bobby to advance the intake back to the recommended dial. He had originally retarded the cam to help the bike build more top end. After he dialed it back to 108* we got a lot of the bottom and all of the mid back. We lost about 1hp on top.
This latest dyno shows the curves uncorrected. I personally printed it out today. The shop was jumping alive being it’s a Saturday and I hated to bother any of the employees to help me print it out. So I went to the Dyno Workstation and did the best I could. The scales look a little bogus and the graph is shy. The actual corrected numbers after dialing the cam forward were 86.4 hp and 60.4 ft-lbs. But you can at least see the base run of the Stock Zilla and the new 1200cc version.
Considering the fact we were stuck with the OEM exhaust I wasn’t too disappointed. We had gained 15.6 hp. That’s almost a 22% gain with no header. Now my only problem was finding a Supertrapp or Kerker. The reason I am bent on a Supertrapp or Kerker is because all the reading and research I’ve done talking to people like Dan Hodges indicates that Kerker/Supertrapp is the best choice for highly modified engines. Though the Motad would be a great choice for a replacement or minor mods (ie…re-jet and K&N) it simply wouldn’t flow enough to support 1200cc of fire breathing Japanese beast. The OEM pipes don’t do this motor justice either. So I’m just gonna have to take it on the chin and belly up to the table for a proven performer. $530! Ouch!
The good news is I found a Kerker yesterday. “The” Guru of XSives…the High Priest of Temple Eleven
in Kansas City…Bobby Jones…actually had a Kerker in his possession. It came off one of his personal bikes and he was willing to part with it. Apparently he’s rebuilding his bike to some new prototype called an SSR/2. I suppose you can go to www.merriamcycles.com and check it out if you are so inclined.
The Kerker should be here mid-week. I will install it and strap Mr. Zilla back onto the Dynojet for a final tuning. Typically with a good header and re-jet you can expect to see 10 to 15% gain in peak power and a nice fat boost across the entire range. If that happens in this case (as it should) the Maxim will be ringing up something on the order of 95 and 65 ft-lbs of capital “T”. And if I take it to Tulsa or OKC to run it on a “motorcycle” dyno we might even see it drift into the magical realm of 100.
But I ain’t holding my breath!
Don’t hold yours!
I’ll be updating this in a week or so.
CYA XSives
Comment