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[Roadrunner]

Hope someone can help here. Built a 1960 Crusader Sports engine, new barrel, piston, rings, new camshaft, new valves, new guides, new valve springs, new pushrods, cam followers correct, everything I can think of. BUT there is no compression in the motor. I run twins usually, and they have bags of compression, but on the 250, nothing. Bore is honed, I also have a +.040 barrel and piston which I swapped out to see if that would help, no difference. I set up the valve timing with a disc, I set it up with the dots. Its doing my head in. Is there something stupid I have missed?

[Alan R]

Hi Roadrunner--------Ouch !!.......and after all that time and money too....Just to help us, is this non-compression like not having the cyl. head on at all ie no resistance to the kick starter OR}-- is there some but very small compression??---------Squirt some eng. oil into the plug hole and replace plug...Work the engine over a few times .... With the air filter etc. removed open the throttle fully and lock it in this position...Now put one hand over the carb inlet and work the kick starter a few times.....Can you feel any suction at all ??...........Further thoughts}--- When valve timing what tappet settings did you use ??......Just for these test purposes re-set your tappets to be "rattling" at TDC compression stroke....Let's say nip-up to nil then half a turn back and lock-up....Try the kick starter....This is just to take a possible tight tappet out of the equation.....More from others soon I hope ??

[Ian Martin]

Some years ago I rebuilt a Panther 650 engine and left it under the bench while I restored the rest of the bike. Fitted the engine in the frame about 6 months after its rebuild and when I tried to start it....no compression. The fault was eventually traced to a sticking exhaust valve which had stuck in the open position. Could this throw some light on your problem?

[Mark M]

With yhe rocker cover off, are you sure the valves are opening and closing? Do you have the right pushrods and cam followers? There were some changes to the valve geometry about 1959-60. Are the piston ring gaps lined up? Is the clutch slipping so much it's not actually turning over? All these things have happened before! REgards, Mark

[Alan R]

Hi Roadrunner-----------any news ??

[Leon Novello]

Is it a low-compression piston?

[Alan R]

Hi Leon, Not that one mate !!---------approx CR 13:1 -------Suzuki 600 racer --------OK, I cheated !! Less than 2 mins with Google Search and a wee bit of "Reverse Engineering" and a visit to Suzuki's web site.....but well worth the effort...I'd not heard of "Perforated Piston" Technology before...You learn something new every day ( and all before Breakfast you'll note.. ).....Big "Thank you " for the image........meep-meep

[Roadrunner]

Many thanks for the replies.
One word. SNOW!!
I have struggled to get in the garage over the past month due to the miserable weather conditions. It has been below zero for the past few weekends and yet more snow last week. I did try the oil down the bore and there was an improvement in compression, but the battery needed a charge, and I didn't have enough time. Will try again this weekend!

[Beezabryan]

If you now have some compression I might suggest getting it fired up, chances are compression will return. Happened before, may happen again

[Roadrunner]

Okay. Took the plug out, stuck in a bit of oil and got a little bit of compression. So switched on the petrol, primed it up, and tried some kicks. The most I got was a pop on a couple of kicks, which tells me the timing is okay. It just doesn't have enough compression to catch and just fire up. I'll just keep trying....