Breaking in of Jawa 250cc Rebuilt Engine

Hii, I have a Jawa 250cc In India,
I recently replaced the Engine with a new Cylinder kit & New Standard
piston set
I have Run the Bike for 2500 Kms, but still the engine seems to seize
when run for
speeds inn Excess of 60kmph for more time like 5 minutes.

What should I do to stop this siezure from happening?

What do people do to Run in a new bike for Racing is there a
posibility,
to follow any rules so I can do it on my bike?

Regards Abhi
India

wrote:
> Hii, I have a Jawa 250cc In India,
> I recently replaced the Engine with a new Cylinder kit & New Standard
> piston set
> I have Run the Bike for 2500 Kms, but still the engine seems to seize
> when run for
> speeds inn Excess of 60kmph for more time like 5 minutes.
>
> What should I do to stop this siezure from happening?
>
> What do people do to Run in a new bike for Racing is there a
> posibility,
> to follow any rules so I can do it on my bike?
>
> Regards Abhi
> India


Hello Abhi

It seems you have got lost in the newsgroup section somwhere !

You have anded up in the Aircool Volkswagen section.

Good look finding the right place and with your bike.

Rich

On Fri, 15 Feb 2008 11:57:24 +0100, Tricky >
wrote:

> wrote:
>> Hii, I have a Jawa 250cc In India,
>> I recently replaced the Engine with a new Cylinder kit & New Standard
>> piston set
>> I have Run the Bike for 2500 Kms, but still the engine seems to seize
>> when run for
>> speeds inn Excess of 60kmph for more time like 5 minutes.
>> What should I do to stop this siezure from happening?
>> What do people do to Run in a new bike for Racing is there a
>> posibility,
>> to follow any rules so I can do it on my bike?
>> Regards Abhi
>> India



Sounds like you are running lean, try larger main-jet in your carb(s).
Also try a higer grade(Quality) of oil if it is available.

Is the 250 a Two cylinder engine?
Is it a injector oil system or pre-mix?
If pre-mix, increase oil amount slightly, try 2,5 - 3% of high quality
TT-Oil.

If it has an oilpump and injector system, you can increase oil-mix by
adjusting the oilpump.
Normaly this is done by turning the cable adjuster outwards, try two full
turns.

One problem now after it has seized several times is the Aluminium smear
on the piston, make sure the piston rings are free and not sticking.

If no other factor was changed after installing cylinder and piston kit,
the seizing is caused by a to narrow piston to cylinder tolerance(gap).

If this is a performance(tuning) cylinder, you will be turning higher
revs. and need a richer fuel to air mix. As above, you need a larger
main-jet with slightly increased oil mixture. If the cylinder and exhaust
allows for high rpm, you need a full synthetic high quality two-stroke oil.

Hope this helps.

J.

Ps.
Did you alter the ignition point when you replaced the cylinder? To late
and it will run very hot, to early and it will ping..(melting a hole in
your piston).





>
>
> Hello Abhi
>
> It seems you have got lost in the newsgroup section somwhere !
>
> You have anded up in the Aircool Volkswagen section.
>
> Good look finding the right place and with your bike.
>
> Rich



--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

On Feb 15, 5:57*pm, "P.J.Berg" > wrote:
> On Fri, 15 Feb 2008 11:57:24 +0100, Tricky > *
> wrote:
>
> > wrote:
> >> Hii, I have a Jawa 250cc In India,
> >> I recently replaced the Engine with a new Cylinder kit & New Standard
> >> piston set
> >> I have Run the Bike for 2500 Kms, but still the engine seems to seize
> >> when run for
> >> speeds inn Excess of 60kmph for more time like 5 minutes.
> >> *What should I do to stop this siezure from happening?
> >> *What do people do to Run in a new bike for Racing is there a
> >> posibility,
> >> *to follow any rules so I can do it on my bike?
> >> *Regards Abhi
> >> India


When I worked at a motorcycle shop in NY the only Jawa's we saw were
flat track bikes that were only meant to run 5 min, at full speed. No
brakes even in fact they just ran the oil thru the frame. It was
popular weekend racing in that area.

Mario
oh wrong news group

> schreef in bericht
...
On Feb 15, 5:57 pm, "P.J.Berg" > wrote:
> On Fri, 15 Feb 2008 11:57:24 +0100, Tricky >
> wrote:
>
> > wrote:
> >> Hii, I have a Jawa 250cc In India,
> >> I recently replaced the Engine with a new Cylinder kit & New Standard
> >> piston set
> >> I have Run the Bike for 2500 Kms, but still the engine seems to seize
> >> when run for
> >> speeds inn Excess of 60kmph for more time like 5 minutes.
> >> What should I do to stop this siezure from happening?
> >> What do people do to Run in a new bike for Racing is there a
> >> posibility,
> >> to follow any rules so I can do it on my bike?
> >> Regards Abhi
> >> India


When I worked at a motorcycle shop in NY the only Jawa's we saw were
flat track bikes that were only meant to run 5 min, at full speed. No
brakes even in fact they just ran the oil thru the frame. It was
popular weekend racing in that area.

Mario
oh wrong news group


http://www.speedway-grasstrack.nl/20...ad-4-mrt/6.JPG

http://www.speedway-grasstrack.nl/20...ad-4-mrt/5.JPG


--
Arrie

Performance Bikes: The Navigator eats corners and spits out rocks afterwards

Back in the 1970's the USA Jawa distributor folded and 125 and 250cc
Jawa tw0 stroke singles were dumped on the market dirt cheap. I
considered getting one just for the oddity of it but I figured getting
replacement parts would be unobtainable.

Good service info was already provided so all I will ad is; before any
failed two stroke engine is rebuilt from a top end failure, the reason
for the failure needs to be addressed before rebuilding the engine or
you will end up doing it all over again....

Tony