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Author: Subject: First drive
johnhsmith

posted on 17/2/19 at 07:12 PM Reply With Quote
First drive

You may remember my setup.....cvh engine, Yamaha R1 carbs, Canems ignition.
I have just today finally driven the car on the road legally and for more than a few hundred yards. Had obviously wound the springs up massively too high so it was fairly scary to get home. Adjusted them and now a lot better but I think they may still need some adjustments. I may call round to Matt at Procomp and say hello, he wasn't very well last time so I hope he's better now.
The engine runs but backfires a lot and is not at all smooth. I have managed to balance the carbs but I think I probably need to start at the beginning and tune them first.
However, one of the biggest problems is that the revs are so slow to die down. I took great care to ensure that the throttle linkage was free and I'm sure that it springs back to the stop fine, but most gear changes are done at 2,000 revs. You can imagine how horrible it is to drive like that.
Can anyone point me in the right direction to sort that?
If I am to to adjust the pilot screws the Haynes manual for the Yamaha tells me to start with pilot screw settings 2.5 or 3.125 turns out for 1998/1999 or 2000/2001.
I don't know which model carbs I have yet, does anyone know how I can tell which year they are?
Any advice would be great.
Thanks

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Dingz

posted on 17/2/19 at 07:30 PM Reply With Quote
Pilot screws won't affect the problem you have, but I would start at about 2 1/2 turns. Check that you have strong enough return spring to close the throttle quickly. Could be sticking throttle slides or possibly air leaks on the inlet manifold.
Are all the vents on the carbs open?





Phoned the local ramblers club today, but the bloke who answered just
went on and on.

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Slater

posted on 17/2/19 at 09:01 PM Reply With Quote
Bike carbs need a throttle return spring fitted to the rotating shaft via a quadrant in order to close quickly. Have a search on here, some pics in my archive too.

I used 2 springs, a Short section of cable with nipple and 5p coin with hole drilled in.

A bike throttle has 2 cables. One to open and one to close.





Why do they call Port Harcourt "The Garden City"?...... Becauase they can't spell Stramash.

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Dingz

posted on 17/2/19 at 10:32 PM Reply With Quote
Mine just use the standard R1 return spring but I have a return spring on the pedal.





Phoned the local ramblers club today, but the bloke who answered just
went on and on.

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mikeb

posted on 18/2/19 at 07:52 AM Reply With Quote
Air leaks from your inlet and mounting rubbers/hoses is a likely cause
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rusty nuts

posted on 18/2/19 at 10:06 AM Reply With Quote
Check for air leaks , carb balance and for over advanced ignition timing..
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