CB125t engine tuning in Wellington?

[bikemad311]

Hi there, I was wondering if anyone has any idea who I could call in the Wellington area about getting some engine work done on a 1981 honda CB125T motor. I know that these are getting a bit long in the tooth now but my dad gave me the donor bike so I would like to see what could be done with it and get some idea of cost. I am pretty sure its the motor with the high lift cam, although it doesn't have flatside carbs on it. I am in the process of building a FZR 3LN chassis to run it in. From what I know these motors can be bored out to 142cc but am unsure of what gains maybe made with upping the compression and giving everything a bit of a tickle up (lightening, porting etc). This motor will end up back in the honda chassis which I am turning into a cafe racer, but I would like to run it on the track for a bit. I've also heard that a 12volt conversion is possible using a loome and cdi from the later superdream, which might be a good mod. Any suggestions from you guy's would be great
Cheers

[koba]

Hi there, I was wondering if anyone has any idea who I could call in the Wellington area about getting some engine work done on a 1981 honda CB125T motor. I know that these are getting a bit long in the tooth now but my dad gave me the donor bike so I would like to see what could be done with it and get some idea of cost. I am pretty sure its the motor with the high lift cam, although it doesn't have flatside carbs on it. I am in the process of building a FZR 3LN chassis to run it in. From what I know these motors can be bored out to 142cc but am unsure of what gains maybe made with upping the compression and giving everything a bit of a tickle up (lightening, porting etc). This motor will end up back in the honda chassis which I am turning into a cafe racer, but I would like to run it on the track for a bit. I've also heard that a 12volt conversion is possible using a loome and cdi from the later superdream, which might be a good mod. Any suggestions from you guy's would be great
Cheers


There is heaps you can do with these.

Downsides are weight, difficult crank rebuilds.

12v shouldn't be too hard.

Rocking up to Kaitoke is probably the best first step, come have a yarn. There have been a few pretty fast ones locally (a while ago now), 142cc is conservative, you can go bigger. I think it's pretty easy to hit 152 or something (Legal for buckets when considering overbore allowance).

I'll mention this thread to a local guy with a good amount of experience in these, he knows the good picks for pistons etc.

Heaps of fast ones have come out of Auckland too, thanks to John Connor.

[koba]

Also, I suspect it will never get back to cafe racer once you start playing with a proper racer!

[bikemad311]

There is heaps you can do with these.

Downsides are weight, difficult crank rebuilds.

12v shouldn't be too hard.

Rocking up to Kaitoke is probably the best first step, come have a yarn. There have been a few pretty fast ones locally (a while ago now), 142cc is conservative, you can go bigger. I think it's pretty easy to hit 152 or something (Legal for buckets when considering overbore allowance).

I'll mention this thread to a local guy with a good amount of experience in these, he knows the good picks for pistons etc.

Heaps of fast ones have come out of Auckland too, thanks to John Connor.

Cheers for that mate, it would be great to talk to someone with a bit more knowledge on the subject. I will definitely be coming out to the track again soon. I was out there a couple of months ago but have been away on holiday and since then I've been trying to pay for it. Looking forward to getting the thing up and running properly and going racing, looks like a brilliant way to spend a day

[koba]

Cheers for that mate, it would be great to talk to someone with a bit more knowledge on the subject. I will definitely be coming out to the track again soon. I was out there a couple of months ago but have been away on holiday and since then I've been trying to pay for it. Looking forward to getting the thing up and running properly and going racing, looks like a brilliant way to spend a day

it is.




......

[jasonu]

Hi there, I was wondering if anyone has any idea who I could call in the Wellington area about getting some engine work done on a 1981 honda CB125T motor. I know that these are getting a bit long in the tooth now but my dad gave me the donor bike so I would like to see what could be done with it and get some idea of cost. I am pretty sure its the motor with the high lift cam, although it doesn't have flatside carbs on it. I am in the process of building a FZR 3LN chassis to run it in. From what I know these motors can be bored out to 142cc but am unsure of what gains maybe made with upping the compression and giving everything a bit of a tickle up (lightening, porting etc). This motor will end up back in the honda chassis which I am turning into a cafe racer, but I would like to run it on the track for a bit. I've also heard that a 12volt conversion is possible using a loome and cdi from the later superdream, which might be a good mod. Any suggestions from you guy's would be great
Cheers

Ride it as it is and save up for an FXR. That will be way cheaper in the long run.

[bikemad311]

I hear what you are saying, and I have given it a lot of thought. I am wanting to sort this motor as it will eventually go back on the road in the original frame. The donor bike is another project which is a ground up rebuild in a cafe racer style, new shocks forks brakes bodywork etc so I would like to get this motor sorted and when the rest of it is done I'll bolt it back in.

[mr bucketracer]

a fast fxr is about the same as a fast honda twin , just the weight

[F5 Dave]

I hear what you are saying, and I have given it a lot of thought. I am wanting to sort this motor as it will eventually go back on the road in the original frame. The donor bike is another project which is a ground up rebuild in a cafe racer style, new shocks forks brakes bodywork etc so I would like to get this motor sorted and when the rest of it is done I'll bolt it back in.
Is it worth it? As non std it won't be worth anything to a nostalga freak (I'm restoring a T125 Stinger on the slow) but rego etc makes it unviable to use as anything but a quick out of sight of the law type ride.