Yamaha Speed MX, a rare two stroke bike in Thailand BLOG
1/8/10: I have been looking for a nice 2 stroke bike for a racing project, a friend of mine has the same bike, he wont sell it. I was working on my X1 and I saw an old man cruising the block not exceeding 2nd gear, he is about 65yo. I thought if I could get Grandpa's bike it may be a good project bike.
I saw him go past one day, and I chased him down, and spoke to him in my best & politest Thai that I could. He eventually agreed on a price and I acquired the bike, Grandpa now cruises on a bicycle, he said its better for him, no need spend money for gas.
The old guy never dropped the bike, it is in pristine condition for a Thai owned bike, it has never been in an accident, everything is original and mint.
I acquired the mint race bike for 13,500 baht or $400, my mechanic friend says its expensive, but its a bargain for me, everything is mint!
I gave it a bath, stripped off the seat, took it to a seat specialist shop for a re-cut and new skin (200 baht or $6.00). I stripped off all the plastic fairing parts and took it to the race bike shop for a pearl white spray and re-finishing. The theme for this bike will piss off anyone I rip past or race with, Thai people just love their bikes and spend everything into them.......it will be sick when they get beat by an old bike with pink hello kittys on it.
I figured I could easily take the bike to a full race mod or a stage 4 as I know it. I started with removing the oil pump and reservoir, and made a plate and gasket (similar to a budwiser box material) to cap off the hole, plugged up the oil lines and removed all the stupid shit. I will end up doing a stage 3 mod, milled head, premix, polished exhaust port, re-gear for a longer wind up, and mod the carb.
I was very disappointed to find out I dont have to port the bike out, the exhaust already matches the expansion chamber, its fairly massive, I will mirror polish the exhaust port, and mill the head and recut the squish band and polish the dome to really make the bike sing a tinny 2 stroke song! I will decide what to do with the carb when I get there, I may go with a K&N style air-pod and re-jet it properly.
I thought I would have to do a re-bore and bigger piston, but the cylinder was free of any scoring or wear, the piston looked like it was only 1/2 a year old and driven to the temple on sundays and to go shopping. I will buy a set of rings and a new con-rod bearing. I am trying to de-carbonize the inside of the pipe, I am using gasohol, nuts, bolts, sharp scrap metal, I remembered to count all the pieces before inserting them! If I can not clean it right, I will just buy a new pipe for 500 baht or $15
1/10/10
I spent the day polishing the exhaust port, it has a mirror finish now, before and after:
I am going to look for an expansion chamber, I found out the yamaha one is baffled inside and is not a true racing pipe, its heavy and full of carbon from the old guy putting around on it. I take the head to a machine shop tomorrow, I was quoted 100 baht to mill off 0.40 or take it to the fins as I know it. I painted the spot red, and scribed a line for the machinist to follow.
1/13/10
I got the milled head back and it was only 60 baht to mill, or $2.....amazing thailand! I recut and polished the dome and tested it for leakage, it went fine...........harder to kick start now.
I managed to find an expansion chamber, it was 650 baht, I had to butcher off the j-pipe from my old pipe and fit it and hang it on the bike with a wire. I then pushed it a block to the muffler shop, the kid there must of just gotten out of tech school, but he was killer at welding and brazing, the pipe got a new hanger and was brazed onto the j-pipe. The silencers angle did not look right, they bent the silencer in and up to the correct position, the owner of the shop is a real smart and nice guy. Cost 140 baht $4.00....the kid did such good a job, I gave him a tip of 50 baht. The pipe has a good hollow sound, a bit tinny and peppy at throttle, I have to re-gear the front sprocket now, because I get to the redline much quicker now.
I got a stock genuine yamaha foam air filter and replaced the rotten one, I installed a new spark plug and ran around the block, I have a black spark plug, so I will try to lean it back a bit. Originally it had a black sooty plug in it.
I did some runs on the back roads here, people pull to the side and slow down out of respect, they fear the sound of a racing bike, one jackass tried to chase me with a honda wave 100, he saw my rear tire and smelled smoke, he couldnt look me in the eye after getting destroyed!
1/14/10
Back from the paint shop! 800 baht or $20 A beautiful white w/ pink & blue pearl, those guys did a hell of a job! I decided to do a rebore and new piston, took 3 hours to have done and 300 baht for everything. A new clutch assembly will be installed tomorrow
1/15/2010
Well the shop that sold me the clutch plates gave me the wrong size, the mechanic said the original plates were fine, not ridden hard. Earlier he recommended I buy some springs from dangs race shop, those were installed and everything is like new. Springs 180 baht, labor 200 baht.
I bought custom made pink yamaha stickers and some pink hello kitty stickers, the bike now looks like a girls bike, it will be sick to get beaten by some girls bike! Stickers 300 baht.
1/19/10
The other night I got beat by my friends old speed mx, I tested his bike today and it has a no limit CDI, I need to get my hands on one too, his bike can do 40 kmph in 1st gear, 80 in 2nd..............sick!
I am looking at pulling the flywheel and having it milled for lightness. The bike is on the 2nd tank of break in gas because of the rebore, once finished, I will mix at 40 to 1, I may do a special race mix gas additive too.
1/21/10
I been looking for a racing CDI without a rev limiter, I read on some boards that an aftermarket CDI made in Thailand is unrestricted, a new restricted one is 1900bt from yamaha, dangs race shop sells them by special order only for 1700bt. I went to my favorite store that a nice chinese thai lady owns, she had an aftermarket thailand made one for 800bt, I slapped it on and sure enough, at 30kmph no limiter, 40kmph was redline in first gear, so its possible to do 80kmph in 2nd gear like my friends stock bike does.
I have already changed the stock 14 tooth front sprocket to a 15 tooth, because I have high compression head mod. I modified a carb needle to the right length, it is off a similar vm22 carb, and has a slow taper and 5 height adjustments. I installed this for a leaner mixture, I'll switch to the K&N style airpod later, I have a cool looking one made of stainless steel mesh, I hope the spark plug color goes to a cocoa brown.
1/22/10
I am switching back to the 14 tooth sprocket, the 15 is good for highway usage, I am riding in town, so I'd like to have a quick bike...............youtube video added
1/23/10
New stickers added for the girly bike effect!
I welded a custom rubber coated T-bolt to keep the kick starter off the newly painted panels, the kicker can only get 1/2 inch near the painted panel. Its by the oil plug, or in the middle of the kicker.
1/26/10
got the bike to 60 kmph in 1st gear today, I have the gas/oil mix at 45 to 1............freaking scary for how quick it is!
2/8/10
I go and buy an expansion chamber that is what looks like a drag race pipe, I did some research and from what I remembered, a short cone/stubby pipe is for low end like on a motorcross bike, and a long cone is for mid to high speed as in GP track racing.
I paid 450 baht for it, and welded the j-pipe on myself at very low power with my welder, it does not leak, but the pipe is very loud at mid range cruising
My first test pass on the bike was scary, the power band kicked in at 20 km/h and went to 60 instantly, the G-force pull back on the body very scary if you are not used to it, it "straightened out my arms" and snapped my neck back, I was not ready and too relaxed, 2nd gear did the same thing when the power band kicked in, same neck snap and G-force. This thing has some serious off road power, its loud, raucous and should be used by experts only or for drag racing, if a turn was done, and too much throttle was applied, the rear tire might spin out, fish tail, break traction, and would be ugly. I may change the pipes silencer tomorrow, it needs a longer silencer.
The bike can wheelie for 50 meters or more at 1/2 meters off the ground in 1st gear without clutching same as my RZ 350 yamaha, I think if I had enough room, I could shift in the air and hold 2nd gear for another 30 meters.
2/9/10
After doing some research, I learned the stinger pipe needs to be a certain length, and I decided to gut the strainer tube silencer and add a big hole strainer tube. The combination of the new tube and stinger extension made the sound more mellow, but its still loud, everyone on bikes pull over to the side of the road to let me pass, one guy packing his girlfriend made a comment and gave a look like "what an animal that guy is" yep he is right, and his sissy yamaha fino sucks dick!
2/15/10
I lost the first stinger tip I installed on the road somewhere, so I made another one, if you fire up the bike without the stinger tip, its very loud, with the stinger tip on, its loud.............people freak out on their bikes and pull over to the side to let you pass!
3-22-10
I decided to swap silencers on the pipes, the drag pipe has a quieter silencer now, the pipe is still a little loud and still scares the average thai (which is what I want) they do not do stupid things in front of me now and they pull over to the side, they did not do that when I had the old quiet pipe on. Cost me 80 baht in machine shop fees to get some respect!
