65 to 80 or 100

[Padmei]

What's involved with increasing the ccs of a R65 out to a 80 or 100?
Is it a case of just new barrels & piston? New head needed?

There seems to be a lot of R65s around for quite cheap & wondered if easy enough or worthwhile to bore them out a bit.
cheers

 

[Padmei]

Just had a look at specs & notice the 65 has a much shorter stroke than all the rest of them. What's up with that?

Is the increase of torque between the 80/100 noticeable?

I take it the rest of the engine to be identical to other models?

 

[ahebron]

Hi Padmei, I have seen kits to go from 750/800cc to 1000cc but none from 650cc. Check out Motorworks or Motobins.
I guess you might have answered your own question.

Adrian

 

[VAL. H.]

What's involved with increasing the ccs of a R65 out to a 80 or 100?
Is it a case of just new barrels & piston? New head needed?

There seems to be a lot of R65s around for quite cheap & wondered if easy enough or worthwhile to bore them out a bit.
cheers

Just had a look at specs & notice the 65 has a much shorter stroke than all the rest of them. What's up with that?

Is the increase of torque between the 80/100 noticeable?

I take it the rest of the engine to be identical to other models?

It sounds like you will at least need to change the barrels, heads, carbs, and the crankshaft. You might also need to do something with the air box and the ignition setup as well. Oh don't forget the gearing will be different too. So might necessitate a change of gearbox and final drive.

By the time you've spent the extra money and time, you would probably have been better off spending the extra in the first place. Unless that is, your up for the challenge.


Val.

 

[Arch]

R65

Why bother there just as much fun as they are

 

[VAL. H.]

Why bother there just as much fun as they are

What are they like with a chair on the side? I too am looking for a cheep airhead that I can either bob or run a light-ish chair, maybe both.

Would they be man enough? After all the Urals are only 650's, though I'm sure they would have much lower gearing.


Val.

 

[r100gser]

650 to 800 or 1000

the 650 motor is has a shorter stroke the the 800/1000 motor - you will have to change the crankshaft and the top ends.it would be more practical to buy another motor

 

[Padmei]

Thanks guys
I don't think I'll go down that path.
I will test ride one & a 100 & see if I like it. cheers

 

[Rob Farmer]

The 65 was available in either 27BHP or 48 BHP configurations. If you get the right spec one you won't need to upgrade it. Most of the 81 on bikes were at least 48 BHP which is the same as the R80 anyway.

You'll probably find it's a better engine than the 80 anyway.

 

[VAL. H.]

The 65 was available in either 27BHP or 48 BHP configurations. If you get the right spec one you won't need to upgrade it. Most of the 81 on bikes were at least 48 BHP which is the same as the R80 anyway.

You'll probably find it's a better engine than the 80 anyway.

Rob, how can you tell which one you're looking at?



Val.

 

[Rob Farmer]

http://www.bmbikes.co.uk/chassispages/enginechassis650.htm