CB125T racer 12,000rpm dyno run

My daughter's Honda CB125T racer gets a run on the Tim Blakemore Racing Dynojet Dyno after some engine modifications. Following re-jetting the bike ran to 13,000rpm on a later run: producing 15.04bhp.

Category:

Autos & Vehicles

Tags:

• CB125T
• racer
• dyno
• Blakemore
• Racing
• Bristol

[kiwiavi]

I hope to get onto the CB125T later this year. We are allowed 150 cc in F4 racing and I have a 150cc upgrade kit. My current single can be viewed at

I hope to get onto the CB125T later this year. We are allowed 150 cc in F4 racing and I have a 150cc upgrade kit. My current single can be viewed at

Search CB150 12500 (Can't seem to paste a link)

About 18.5 hp.

About 18.5 hp.

[Kompins]

Hi Kiwiavi,

Nice machine mate.

I love the little Honda engines.

My wife is coming out of retirement to race the 125 this year so it has been freshened up with a much modified Dyna S CB750 ignition. Hopefully this will cure a miss fire above 12,000rpm.

Also building a new engine with lightened crank and maybe home made pistons.

[tpvalley]

@Kompins

I had a missfire at high rpm and found it was to weak a spark and it actually ran better with a smaller than standard plug gap!?

Isnt the standard max power at about 13,000rpm on the 125 twin?

I looked at one cb125 twin engine and it had inlet ports of only about 10-15mm; but I heard that some engines were of lower restricted power as the standard was about 16bhp, so did they make a restricted version with the small ports for smaller carbs?

[Kompins]

@tpvalley I run Dyna coils and a total loss ignition system, big fat sparks until the battery gets below 10volts. See my comments above about rear wheel horsepower and rpms. The CB125TA was the non restricted version for the UK, later versions have small bore exhausts and a retard in the electronic ignition to limit power.

[Kompins]

Honda claimed 16.5hp @ 11000 rpm. This was emphatically NOT at the back wheel, rear wheel hp was more likely 13.

Manufacturers claims of hp were based on crankshaft hp and usually optimistic at that Honda! For example they claimed 42 for the CB500T but when tested in 1975, actual rear wheel hp was 33.5! CBX1000; they claimed 103, actual 85.5.

[OZLAVERDA]

Beautiful sound ... just excellent

[Kompins]

Yes it sounds wonderful, I would love to take it for a run around a race track but it would destroy the sound meter!

[ijzerable]

very nice!

[bravo3000pirate]

your daughter has taste!

[Scootertuner1000]

@jonesjpthrower The CB100 was a single cylinder engine. The CT125T is a two cylinder with twin carbs. In standard trim it put out 17hp at 11,000rpm. The 100 cc engine was a single and was also available as a 125 and a 185.