SERVICE MASTERLIST FOR
2-STROKE ENGINES
2-stroke engines in Japanese and Euro dirt bikes 1969-2012
CYLINDER HEAD MODS $30
This service includes all machining modifications per situation and application. Services include gasket surfacing, turning, clearance-machining for big bores and or strokers, flat-top piston conversions as well as hemi and conical dome shaping, lowering compression for low octane pump gas with ethanol, raising compression for high altitude, TIG-welding, o-ring groove cutting, plug-hole turning and threading. Send the cylinder head for service.
POWERVALVE SERVICE $30
Powervalves are built into the cylinder around the exhaust port. They’re supposed to make the exhaust port bigger when you twist the throttle open. Powervalves are complicated mechanisms prone to failure. We know what parts break and we usually stock them. We offer a service to clean, inspect, and adjust the powervalves. This service comes standard with all porting and big bore packages. Send the complete top end assembly for service.
CYLINDER BASE and HEAD MACHINING $75
Cylinder head and cylinder bases can be turned and machined to produce a powerband that is better for beginners and trail-riders. The technical reasoning is that this modification serves to retard the port timing and increase the squish velocity produced in the cylinder head. If you just want more low-end power and don’t want to spend a fortune, this is the best mod that will give you the biggest bang for your buck! Includes light diamond honing to ready the bore for new piston and rings. Send the complete top end assembly for service.
CYLINDER PLATING (aluminum cylinders) $275
Most modern dirt bikes use hard coatings applied directly to the aluminum cylinder bore. Nickel-composite plating is the hardest low friction coating available. We can plate a cylinder back to original size or to a big bore size for no extra charge. 1-Year warranty This service includes cylinder head resurfacing, stud removal and thread repair, and powervalve service and assembly on applicable models. Send the complete top end assembly for service.
CYLINDER PLATING (iron cylinders) $275
This service is especially great for vintage cylinders with cast iron sleeved bores and CR500s. It is designed to preserve the bore at a particular size. Nickel-composite coating that is very hard and longwearing and comes with a 1-year warranty. Send the complete top end assembly for service.
BORING and HONING for iron-lined cylinders $50
This service includes cleaning, boring, diamond-honing, port chamfering, exhaust bridge relieving and polishing. We offer Wiseco, Pro-X, JE, Athena, Magnum, and Vertex piston kits as well as generic gaskets and bearings. Send the complete top end assembly for service.
2-STROKE PORTING For Japanese and Euro dirt bikes 1990+
All 2-stroke porting packages include the following; disassembly and cleaning of all the top end components, complete porting and polishing, cylinder head machining, base machining, diamond honing, baking soda blasting, powervalve service or epoxy-filling, powervalve assembly and timing of applicable models.
50cc AUTO BIKES $75
Cobra, KTM, Polini; cylinder porting with head mods to push the limit for advanced riders.
65-112cc MINIS $125
Your choice of porting for powerbands that work best for beginner and trail riders as well as national caliber experts in Supermini classes.
125-200cc BIG BIKES $195
Three powerband choices of more low to mid-range, more mid to top end or a smoother broader powerband, plus all of the services listed above.
SCHOOLBOY/JUNIOR NATIONAL LEVEL MX 125 PORTING $195
This service includes cylinder porting and race-ready honing to a new OEM cylinder. You can supply your cylinder for porting or we can sell you a brand new ported cylinder for $400
The porting powerband choices include stadium (low&mid hit) and outdoor (mid-top). Head mods and powervalve service included.
SHIFTER KARTS $195
What a sick twisted form of racing! G-Forces that will give you kidney failure and the ability to cut lap times faster than an Indy car! Eric offers a wide range of services ranging from cloning old cylinders to setting up specs for mx class and IC engines and even clay-oval outlaw racing. Eric specializes in CR125s and also handles all the IC engines like the Pavesi, TM, and CRC,
Eric performs cylinder porting and matching head mods, along with diamond honing of the bore for only $195.
CLONE PORTING $195
Racers are a superstitious bunch and if you have a cylinder that is trashed and you need a new one cloned to the old one for good luck sake, Eric can fulfill your wish. Send the old cylinder and a new one, blueprints or drawings are OK too if the old cylinder is destroyed.
VINTAGE PORTING $185 For Japanese and Euro dirt bikes 1969-89
The vintage mx market is growing rapidly and former barn junkers are becoming expensive collectibles with a lot of rewarding hard work. Racers are prepping spare bikes for VMX and AHRMA events in the US and in countries like Australia, England, and Belgium vintage mx is the biggest class in racing.
Working as a mechanic and tuner since 1971, Eric has accumulated porting specs from all sorts of sources like factory racing directives, practical experience, and the use of modeling software. You might say he’s a bit of a vintage freak and sympathetic to vintage meisters like yourselves.
Eric works on all brands of Japanese and European motocross bikes. If you are a vintage freak and have historical specifications that you would like machined to a cylinder, Eric will cater to your needs. He has also ported cylinders to exact historical factory specifications from Harley Davidson Racing directives from Dick O’Brien to Team Green to Yamaha Wrench Report and even Swedish-language blue-prints from Husqvarna.
Recently Eric built a IT250 for Scott Lind, the moderator of the vintage forum at Thumper Talk. TT did a review of what it was like to restore the bike for vintage mx. Here is a link to the ThumperTalk thread
250-550cc BIG BIKES $225
Three powerband choices of more low to mid-range, more mid to top end or a smoother broader powerband, plus all of the services listed above.
HONDA CR500 PORTING $225
In the glory years of the 500cc Grand Prixs in Europe throughout the mid-1980s and 90s, Eric’s CR500 tuned Hondas were the boss ride. Legends like Jorgen Nilsson and Leif Persson of Sweden, Rob Herring and Mark Eastwood of England, Jacky Vimond of France, and Peter Dirkx of Belgium owned the first turn at the GPs and turned the ultra-expensive HRC Factory bikes into insignificant bridesmaids. At the 1992 USGP at Glen Helen, Swedish champion Jorgen Nilsson holeshot the field in both motos.
In modern days the Service Honda CR500AF’s have reveled in the praise of American dirt bike magazines for the last 12 years. Eric offers porting through Service Honda and in 2006 Dirt Rider magazine ran an Internet Bike Shootout and www dirtrider.net teamed with Service Honda. DR’s test riders demanded that a manual clutch be installed on the bike because the powerband was so smooth they thought the Rekluse auto clutch was slipping. The testers praised the porting and powerband with the smooth powerband with extra revs on top. You can choose the type of powerband and fuel type. Eric builds a lot of CR500s for mx, enduro, desert, hill-climb, dirt track, and ice-supermoto and oval racing.
The porting package on the CR500 includes cylinder porting, base machining, head work, manifold matching and polishing, epoxy porting, soda-blast cleaning, and diamond honing to the next oversize if needed for $225 Additional parts options include your choice of pistons from Wiseco Pro-Lite, Vertex, and Pro-X piston kits $185, Cometic stainless steel gaskets $30, and top end bearings $20 The CR500 porting package with top end parts is $450.
YAMAHA YZ465, 490, & WR500 $225
Starting with the first YZ250A in 1974, Eric tuned and raced YZs through the 80’s as the tuner for DGY Racing. In 1980 he teamed with Troy Bradshaw and hit the nationals. Troy pulled some awesome starts and great placings in the Trans-Am series and soon Team Keystone Yamaha’s sported Eric’s Flow-Ported YZ cylinders. In 1981 Keystone’s Jeff Hicks battled with Team Honda’s Danny “Magoo” Chandler in the Trans Am series. That series launched Jeff Hick’s career as a factory sponsored Team Yamaha rider.
In 1984 Troy Bradshaw made history at Loretta Lynn’s by winning the Open Class championship and besting the factory sponsored riders from Yamaha and Kawasaki whom rode 1985 prototypes and factory bikes.
The porting, cylinder head and carb tuning specs developed in that era can help your YZ run much better and be less sensitive to fuel quality and jetting. The key is improvements in the loop-scavenging through porting and epoxy reshaping. This service includes diamond honing to an oversize. Top end parts are available or you can supply your own piston kit.
BIG BORE KITS 50-550cc 2-STROKES
For model applications check the Big Bore Masterlist
All packages include
Cleaning and disassembly
Inspection and measurement
Over-boring
Porting
Replating with nickel silicon-carbide composite plating
Diamond honing
Head mods
Powervalve service
Piston, gasket kits, and top end needle bearing.
You’ll get your choice of powerbands; more low/mid, more mid/top, broader powerband, and choices of fuel; pump or race gas.
Powervalve timing and assembly
Wiseco top end assembly with piston, bear, gaskets, alignment pins, & seals.
Piston check with ring end gapping
Cylinder bore “break-in finish”, no safety measures needed, just ride!
Backed up by a 1-year warranty on the plating and free updates to the porting and diamond honing. Send the complete top end assembly for service.
PRICES: US Dollars
50-72cc $350
73-112cc $400
124-144cc $500
250-300cc $660
325-550cc $660
BOTTOM END ENGINE REBUILDING SERVICES
Individual and all-inclusive services related to the whole engine or just the components of the crankcase.
CRANKSHAFT REBUILDING $75
Includes cleaning, disassembly, polishing of critical surfaces, rod pressing in an RCE crankshaft jig, and truing. Rod kit extra $80-300. Send the crankshaft assembly for service.
CRANKSHAFT STROKING $350
Includes the same work as rebuilding and relocation of the big end pinhole to change the stroke length of the crankshaft. Rod kit extra $80-300. Requires crankcase boring/porting, and head mods to accommodate the crankshaft stroke change. Send the crankshaft assembly for service.
CRANKCASE BORING/PORTING $100
This service is used in conjunction with big bore stroker mods. Each case half is bored at the center surface to accommodate the clearance of the stroker connecting rod. Then each case half is match-ported to the cylinder and make clearance for the big bore piston skirt. Send the crankcases and cylinder, plus dimensions on the stroker crank.
ENGINE DISASSEMBLY AND ASSEMBLY $300
This service includes internal flushing and exterior baking-soda blast-cleaning and works into disassembly, clean & inspect, precision measuring, and a detailed estimate with performance and durability options like bearings, clutch baskets, cranks, OE parts. Parts are extra. No warranty is included on used dirt bike engine service. Send the complete engine except carb, for service.
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