HONDA EXPRESS SR VRS URBAN

Have been "told" that '81 Honda Express SR engine (NX50) is same as the '82 Urban's (NU50).

1) Anyone knows for sure that this is true?

2) Can we bolt the entire NX engine onto a NU frame with no "modifications" to "make it work?"

3) If engine IS same, does this imply that carb, air box, gas cable, etc. can be also used from one bike to other?

Second issue: After 10 years (covered) we tried to start SR. Couldn't get gas line to provide fuel. Tried experiment: Did a premix, put it in oil tank and tried to start bike. It ran, but the gas seems to flow out of the overflow line on the bottom of the float bowl--if the engine is running or not! You can put the gas in and it just comes right out via the overflow just as fast as gravity allows. Any ideas why this might happen? Solutions? Suggestions?

We would like to take this functioning engine and put it on the larger, more durable Urban chassis if possible.

Thanks for any info.

Re: HONDA EXPRESS SR VRS URBAN

Jonas Quimby /

The two engines are in fact the same with one important differance.

The SR has a smaller back wheel, so the final reduction gearing at the back is differant and would need to be changed.

These bikes use an odd sort of fuel cutoff valve that tends to fail in the shut position, hence no gas.

I'd also highly suggest you take apart and clean the carb until it's utterly spotless.

I wrote a guide to getting a garage sale Express running which you can find if you use the search function. It's for the older NC50, but a lot of the techniques and specifics are the same.

Re: HONDA EXPRESS SR VRS URBAN

Okay...given that issue: How hard is it to change the final reduction gear? We have SOME of the NU engine still on the bike, but couldn't tell you what's there, what's missing yet, since we haven't had time to work it.

I will check on partsfish.com and try to identify from their schematics what the "final reduction gear" looks like. But if you have any other suggestions, please, feel free.

Thanks

Re: HONDA EXPRESS SR VRS URBAN

Jonas Quimby /

On the back of the transmission underneath the cover is a set of gears that connect the transmission to the wheel. These gears are the ones you fill with oil.

If the NU50 still has it's transmission, it probably has the final reduction gears.

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