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Bike-Doc, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 671
Experience:  I have fixed & modified bikes for 35 yrs I'm now THE Mobile Bike Mechanic for S.LONDON since 1990
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Roadstar 1600 ran perfect yesterday tried to start today and

Customer Question

roadstar 1600
ran perfect yesterday tried to start today and it has no compression in either cylinder
Submitted: 1 year ago.
Category: Motorcycle
Expert:  Bike-Doc replied 1 year ago.


Welcome to JustAnswer

Sorry to have to ask what may seem like stupid questions, but it is obviously difficult diagnosing problems remotely, I cannot see, hear ,touch or smell anything & I have only what a customer tells me to make a correct diagnosis of the problem.

Also I dont know how proficient a customer is or what they may have done already. So I need to ask stuff which may seem obvious or unrelated

Thats a bit more than strange, that smacks of sabotage possibly

Can you tell me more please?

How have you disgnosed no compression ?

Customer: replied 1 year ago.
I Pulled both plugs out on left side of bike and just put my finger over the holes one at a time and there was pretty much almost no cylinder pressure when I turned the motor over. I removed the cover from the compression relief mechanism next to the cam cover to make sure it wasn't stuck and it seems to be working . no one messed with the bike it was in my garage. I also removed the air cleaner and there seems to be blow back through the carb . I rode the bike last night and it was running perfectly when I turned it off
Customer: replied 1 year ago.
the bike only has 3000 miles
Expert:  Bike-Doc replied 1 year ago.

Blow back through the carbs means that the inlet valve is not fully closed when that cylinder sparks. So its either a valve, valve timing or ignition timing problem

Take the cover off decompression solenoid and make sure the brass spoon is just touching the tip of the solenoid. Does the solenoid click when trying to start her

Customer: replied 1 year ago.
I removed the cover and the solenoid depresses the spoon when I press the start button. then retracts when I let off the starter button. it seems to be operating properly
Expert:  Bike-Doc replied 1 year ago.

OK I cant tell from the manual how that system works precisely, but there are 2 decompression push-rods, can you tell if they are returning properly pls

Customer: replied 1 year ago.
not sure of the location of the rods or how to access them
Expert:  Bike-Doc replied 1 year ago.

OK they are under the cam cover on RH side of engine

Do you have a manual?

Will you be happy to remove the camshaft etc if necessary?

If so I will get detailed instructions for you

Customer: replied 1 year ago.
ok I will check the operation of the rods in the morning
no I do not have a manual
yes I need to fix the bike no matter what I have to do
Thanks Fuzzy
Expert:  Bike-Doc replied 1 year ago.

OK I will look out the info for you meanwhile

Customer: replied 1 year ago.
I removed the timing cover and the rods moved freely
the rear cylinder now has compression
still no compression in the front cylinder
i was wondering if something may be stuck or bent on the other side of the front cam
not sure if you can view the other end of the cam by removing the right side cover or the cam has to come out
I was also wondering if someone with an intimate knowledge of these motors might say
oh yeah this is what it is it happens all the time
and just so you know I am a certified marine mechanic and I also turn wrenches at the local Harley shop if it was a Harley I would probably have some ideas lol
Expert:  Bike-Doc replied 1 year ago.


Ill throw this question open to other experts who may be able to help you

Good Luck

Rid Safe