As you may have seen from the last update on www.dirtrider.com, I have been putting our 2006 CR125R through the wringer. After being abused like a rental car through break-in, the Dirt Rider and Mini Rider shootouts and a handful of after-work fun rides, I took the little 125 under my wing as my Long Haul bike. With the addition of a new 144cc kit and motor work courtesy of Leavitt Speed Equipment (you can find the full scoop in "Fixing the MXers," May '06), the Honda has been race-ready ever since, and the hours have certainly stacked up.
To say that the CR144 has been ridden hard would be a major understatement. Seeing as the majority of the time put on the bike has been race hours, the outgunned and underpowered 144 has been run wide-open for most of its life. Overall, I am still stoked on the engine, which has definitely helped renew my faith in two-strokes. When ridden in the right spot in the rpm range, the bike is consistent, powerful and clean, and it is more than willing to go toe-to-toe with the four-strokes. It may not be more powerful or torquey, but the 144 has holeshot an entire gate full of 250Fs on more than one occasion! Aside from a bit of detonating (caused by running too much pump gas in the 50/50 race/pump mixture), the motor hasn't had any problems to speak of, and the performance has stayed surprisingly steady considering the hard time on the engine.
At the 35-hour mark, we decided it was time to do a top end, so I took the bike to the LSE shop for boss-man Larry Leavitt to work his magic on it. A quick teardown (those two-stroke top ends are easy!) revealed a very clean, well-oiled piston with surprisingly little wear. Sweet! A bit of blowby was visible on the sides beneath the ring, but the rest of the top end showed absolutely no major problems. Due to the amount of oil on the piston, we decided to lean out the bike a few steps by replacing the 450 main jet with a 420. In talking to Leavitt, I let him know about the bike's lack of bottom and mid, and I explained that the sweet spot on the motor was a little tough to stay in. With this in mind, Leavitt decided to replace the domed GP-style piston with a flattop one, which is claimed to increase bottom-to-mid power and help with detonation. Along with this, Leavitt also did some work on the head in order to gain a bit more power. In hopes that the longer exhaust will fatten up the meat of the 144's power, I replaced the FMF Shorty silencer with an FMF PowerCore 2 when the top end was reassembled. The only other modification that I did was to swap the stock air filter with a Uni Filter, which is thicker and a little easier to clean than the stock unit.
At this point, I am stoked to continue to put time on the trusty 144. Seeing that the engine has withstood such abuse has certainly boosted my confidence in the machine and serves as a reminder that 125s are-contrary to popular belief-built to last. As we go to deadline, I haven't ridden the CR with these latest modifications, but it will be interesting to see how the longer silencer and new motor work affect the powerband. The fork seals, chain and sprockets have seen better days, and I have a feeling that the clutch is getting ready to buy the farm, though I am hoping to baby it for a while longer. I also noticed that the Platinum 1 hourmeter broke again, so I will have to replace that as well. But for the most part, I am darn impressed with the 144, and I will continue to enjoy every minute aboard the bike that I can get. After all, given the current four-stroke boom, these things probably aren't going to be around forever...
Running Tally #2
Hours on Bike: 35
Modifications: $1850.80
Machine cylinder head: $110
Split and match cases: $299.95
Platinum 1 TimeBomb hourmeter: $38.95
Sunline Blast Shield hand guards: $49.99
FMF PowerCore 2 Silencer: $119.99
Uni Filter: $26.95
Maintenance and Repairs: $666.56
Piston kit: $120
5 5-gal. containers VP Race fuel: $49.99 ea.
10 Bottles HP2 Premix oil: $6.99 ea.
3 oil changes
Bel-Ray gear Saver: $6.95