No Power...1600 SP

[froggy]

Took the van out for a drive over the weekend (was planning on going to Stonor) and to be totally honest the van has no get up and go, show it any sort of hill and you might as well get out and walk.
Timing is spot on, carb (30 pict 2) is re-conned and set up according to solex, points correctly adjusted, valves adjusted (numerous times).
Engine revs fine (and now also idles at junctions) but put your foot down and forget it, pulls well in 1st and not to bad in 2nd but 3rd and 4th forget it, struggles to get above 45mph wind assisted down hill foot flat to the floor.
Very Very dis-appointed with it.
Planning on doing a compression test and take it from there but any other ideas?

 

[Trikky2]

Make sure all the adjustments are correct and that the timing is correctly set for the dissy you have and that the timing marks you are using are right. Yes theres still people setting timing using pulleys with the wrong marks on them and setting timing according to the figures in the manual without realising the dissy is not the one originally fitted, to which the figures apply.

Check the advance and vac advance are working. (strobe)

Have a look at a plug or two to see if its running rich or weak.

Check the air cleaner is not blocked.

I could go on and end up writing a manual but you get the idea.

If all checks out then a compression test is your next step to check for a dodgy valve. Its not likely to be a problem with rings since if they were worn you would be using oil and getting a blue smokey exhaust and lots of back pressure in the crankcase.

 

[BJ1]

Also check that the accelerator pump on the carb is actually working by quickly opening throttle whilst looking down the carb choke. You should see and hear a good squirt of fuel. If not your engine will behave exactly as you describe. If it's not working it will either be a blocking passageway/jet or more likely the diaphragm is split.

 

[kev mc]

also check when the pedal is on the floor that the carb is fully open

 

[Ali]

I had almost the exact same problem last year

It turned out to be a small crack in the head, between the valves. It ticked over lovely, revved up lovely, but like you say, show it any sign of a hill and nothing...

I would think your compression check should highlight if this is the case. I didn't do one, instead just started stripping to see what was up.

It was a very fine crack, almost invisible, but as the head warms up, the crack opens up...

Good luck.

 

[froggy]

I'm currently completely rebuilding the engine, there were loose bolts on the heads, on the engine case itself, the rocker arms so decided to strip and fully rebuild it with new bearings.

 

[r73]

hows the build going bud?

 

[froggy]

Bottom end almost complete, didn;t realise that a crank oil seal isn't part of rebuild gasket kit so need to order 1 of these.
Still trying to decide whether to build with single port or twin port heads, occasionally think single as i have everything i need but then think twin to uprate the carb?
Hopefully by next weekend it will be drivable then its time to start on the electrics

 

[r73]

cool beans 8)