Forum

[andy w]

I have been running in my 350 Bullet and have done about 700 miles. I fitted the higher compression Indian piston from our hosts. When first put together the compression seemed low (as gauged by the feel of the kickstart lever),but it started and ran well. The bike is still running well but the compression seems poor and seems to leak away when the kickstart is pushed down.
European rings are listed in the Hitchcocks catalugue,would these help? Any experiences?
I fitted the piston and forgot to check the ring gaps as I should have done.
I am using budget 20/50 oil.
I would appreciate any comments on rings and running in. I was planning to put some more miles on the engine and then strip the top end to check the piston and rings.

[Shane]

HI, this really is a job for a compression tester. Guessing or trying to gauge from the kick start lever is not helpful. A comparison of dry (just put the gauge in, open throttle and kick until the pressure stops rising) versus wet (squirt some oil in then repeat the other steps) will show if the rings are possibly at fault.

[simon]

To test if it's rings get a compression tester and measure the comp as is then retest having squirted a couple of shots of engine oil down the plug hole. If it's rings the compression should go up. I had a dud set of rings sold to me for my Ducati once but it made huge quantities of smoke. It could also be a head gasket issue or valves. I found a leaking gasket once by painting a detergent and water mixture around the junction of the head and barrel when the bike was ticking over. Needs to be reasonably cold obviously.

[simon]

Whoops Shane beat me to it

[scotty]

Rings in the right order, with indian bullets there used to be 1 ring with top marked on it this only indicated top side of ring not its position on the piston it goes in middle groove chrome ring goes on top groove get them wrong and you lose comp and burn oil. My 2 bobs worth.

[neddy]

If you forgot to gap the rings, as Scotty states maybe in wrong order and the gaps are not in line are they

[andy w]

Thanks for the comments. I will get hold of a compression tester and check this. Rings were fitted with chrome ring at the top. Top 2 rings were marked "top" I think.

[Dennis C]

Was the cylinder rebored or deglazed?. If not the rings will not bed in.

[andy w]

The cylinder was rebored from +20 to +40 oversize. The surface finish was not smooth but looked honed with a dull finish and stone markings. Not sure if the finish is correct but the job was done by a local engine reconditioning firm.

[Alan R]

As per SCOTTY------ A while ago I had a Honda PC50 in exactly the same state of repair except that it kept smoking after about 5 mins. running............. All the usual tests done but no joy....Piston off, rings removed and checked with a Spy-Glass..Sure enough I could just make out the word "TOP" on one ring......This was fitted in the top groove with the word "TOP" uppermost and guess what ??-------------------------- YEP, no more smoke !!..... Have just returned fromthe Irish Republic so that's my €1 worth ( approx.75p at the moment..)