Only running on one side

[jerry]

750ss finally running again after 3 years of renovation ,, But only firing on Vertical cylinder ,,

Horizontal has spark at plug and coils and ignighters are fine I swopped them around to test ,, there is fuel in carb too but not going bang on that cylinder ??????


Now the carbs have been stripped , Ultrasounded, cleaned and rebuilt with all new seals etc float valve set same on both carbs ,, no leaks or overflowing ?

Did it all just like on all my other rebuilds and these carbs have been serviced by me 3 times in last 16 years , so Im not sure now what to do next other than open that carb up again and have a look ????

[Mark64]

Electrics is favourite, swap plugs & other components to prove

[jerry]

OK Swopped plugs , HT cables , coils etc but no change all electicals working correctly nice big sparks ,, but horizontal cylinder still not running just spit backs ,, so it must be carb related .. ho hum .. ???? carbs coming off to check ????

[utopia]

I know you're very familiar with these engines and their foibles but I can't help wondering how long you have cranked it for and/or left it running on just the one cylinder.
My own M750 always take ages to fire up properly on both cylinders after a long lay-off and this seems to be related to the float bowls taking an absolute age to refill after their former contents have evapourated.
It is often the case that one cylinder will fire and run for 30 secs to even a full minute (at least it seems like that long) before the second cylinder will kick in.
I assume this is while it is trying to fill the float bowls, which seems to take an awfully long time even on the first cylinder to fire and an absolute age on the second cylinder.
Of course my fuel pump is original and therefore may not be operating at full efficiency after 25 years of diaphragm deterioration, which may be a contributory factor.
Anyway, long story short, it might be worth letting it run for a little longer on the one cylinder to see if the other will eventually kick in, before stripping the carbs.
Or even priming both float bowls with a syringe and tubing like I believe Dookbob used to do.

[jerry]

Ok checked carbs all in perfect order , so back together and try again ,, well is is sort of running on 2 now but not ticking over even with throttle stop screw wound in and it wont balance up properly its definitely firing better on one than the other ,, one side seems lean but when you change over the HT cables it switches to other side so i will try the electricals from the M750 onto the 750ss to see if it improves ..maybe some component is working but weak ???

I have had it running now for 20 minutes so I reckon the float bowls are full ..

time for a cuppa

[Dukedesmo]

Possible poor connection on one of the pickups/coils etc.?

My bike has an Ignitech ignition module rather than the igniter boxes but, shortly after fitting this I had a cylinder cut out on me. One of the wires in the multiplug on the Ignitech had come loose from it's crimp terminal and so was only making occasional contact.

The odd thing is that the bike sounded and seemed fine at idle speed when running on just the rear cylinder and even on the road it didn't seem particularly rough, just wouldn't go above 40/50 mph.

[jerry]

Last time i had this type of problem it was the spark plugs being wrong specification but i have NGK DPR8 so thats correct ones ,,, another time it was one carb with a defective airscrew jet ,,,

I will swop all the electrics over from the monster which is running perfectly and see what happens , i also have spare coils and spark plugs in stock .. but Im not in a hurry now as its too late in the season to get the bike on the road and im off to Thailand and the S4 next week for 9 weeks so 750ss can wait ...when im back for Xmas and the new grandchild I will have plenty time in miserable UK weather in Jan and Feb to get it perfect for spring ....

Also going to upgrade the Monster 750 front forks with Ktech 20mm cartridges as its got feeble damping , giving it a harsh , jittery ride on ny less than billiard table smooth roads.

I have been speaking with some suspension guru's, Brooks, MH , etc They all recccomend Ohlins or Ktech valve and 20mm cartridge kits set to my bike and full fork overhaul etc approx £400 but they dont seem to rate the fully adjustable Adreani .

[Dukedesmo]

Originally Posted by jerry

Also going to upgrade the Monster 750 front forks with Ktech 20mm cartridges as its got feeble damping been speaking with some suspension guru's They all recccomend Ohlins or Ktech valve and 20mm cartridge kits set to my bikes .

My Monster has Showa (916) forks, I had the Ktech valving fitted and they work really well.

I also had Ktech valving fitted to the Ohlins on my 916 and they're even better but they are a larger size, 25 or 30mm IIRC so maybe that's why they work better?

Either way, I'd highly recommend Ktech. I take all my suspension jobs to them and have always received a 1st class service - convenient that they're nearby too.

[jerry]

Duke Desmo my S4 has Showa 996 superbike forks on with Ktech valves and 8.5 springs they are very good now compared to the original crummy showa units ,,, it has Ohlins on rear

The Monster 750 has original un adjsutable showas ,, they have some 9nm Ohlins springs but thats it Im not changing the forks just getting them revalved and the cartridge changed , It also has an Ohlins or rear ,,

The front end is jittery on bumps and it messes with the handling on bumpy roads and with braking also not really compliant at the front compared to the Ohlins at the rear ,, So its time to sort it out .

Now im in Cricklade MH suspension is only 9 miles away and he has 40 years experience with Ohlins and Ktech