compression LeMans V

Technical Big Block Tonti and Loop Frame models
1

I recently bought a Lemon V. I used to own one many years ago. I know that I may have rose tinted glasses however this one runs very well i.e. smooth however it feels under powered . There is no briskness to it on acceleration. I have done a compression test left cylinder is 102 ish and right cylinder is about 92. is that good or bad I cant find anywhere that says what the reading should be. The engine dosn’t miss fire or stutter it is just lazy on acceleration. Feels like an old Harley, (any ideas, help ) much appreciated.

Les

2

That’s bad

Would expect north of 125, but ideally 160

You sure you did it right?

Did you put some oil Down the bores to see if it went up?ianboydsnr2013-09-04 20:44:47

3

How many miles are there on it Les? And does it have any after market silencers/air filters?
Rob

4

Throttles wide open?

5

Unless you are very experienced BEFORE shelling out loads of dosh get the compression test done by a professional …Many years ago I had a “problem” so I thought. Took it to a pro, saved me a fortune as it was a leaky valve. The cost at the time was under £20 and a pair of valves which I fitted and re ground the guy rechecked it gratis, all done.

6

If you can do it, a leakdown test may help more. Pressurise the cylinder at TDC through an adapted spark plug, and listen for the air leaking out.

7

cheers for all your hep guy’s I will do the tests again and see what I get when it is warm etc.
Cheers Les

8

Lack of power is often timing too. Check it with a strobe at about 4000 rpm and see if it reaches the fully advanced marks.

9

Good point, retarded makes lots of heat, but not much in the way of forward urge. Is it contact breakers? If so make sure cam is rotating fully. Clean / lubricate as necessary. You can of course go too far the other way, if your fingers are going numb and fillings falling out it’s probably too advanced

10

What you are talking is very similer to my mk111.160and 140.it was also blowing out oil.So I re ringed it.Problem solved.

11

All of the above and are yer accelerator pumps workin ?

12

Waiting for Les… Again, “smooth” may suggest ignition retarded