Jump to content

New XS400...


plain old dave
This post is 5910 days old and we'd rather you create a new post instead of adding to this one. You can't reply in this post.

Recommended Posts

Do you want an ad-free experience? Join today and help support the Yamaha Owners Club.

Just got one, and am having a heck of a time starting the fool thing. The feller I bought it from had a bit of trouble starting it, and my neighbor got it going with a bit of hassle. It is kick only and I am wondering if I am just not doing it right. HELP!

I guess it is a sohc XS400 ? if so I would check all engine settings, as follows :-

Intake Valve clearence 0.1mm

Ex Valve clearence 0.15mm

Set the ignition timing statically LF on the rotor for left cyl and RF for the right cyl at those marks the points should just open but ensure you have the engine on the correct stroke i.e both valves shut on the cyl you are timming

Clean out carbs (make sure no hole/jet is done also insure the rubber bungs over the jet are ok and fit snugly)

Fit new plugs (in the U.K they were BP7ES but maybe different elsewhere, but make sure the plugs are projected tip type signified by the P after the B).

Obtain a vaccum gauge,strobe & dwell meter.

attach guages,meter & strobe

Start the motor and allow to warm up.

Set the dwell to 22.5% then check ignition timming adjust as required then recheck the dwell. This is a bit of a fiddle you need to obtain the correct ignition timming & dwell so you will have to recheck both a few times !

When this done time to go to the carbs !

Set Idle to 1100 rpm or close to

Check vaccum readings both cyls should be the same and between 20-30 Kg/Cm if not adjust with the screw located between the carbs (the idle speed may alter as you adjust the carbs, if it does reset to 1100 rpm and continue with the adjustment when have the carbs set equal (and within tolerance).

If you cannot get the engine to run with the balance equal but you can with readings of say 20 on the left and 40 on the right its time to take the head off and look at the valves & bores :huh:

But if all is ok move onto the last stage

screw the idle mixture screws inwards until the engine starts to die then screw out until the idle rpm starts to increase (after this you may end up with an idle above 1100 rpm readjust it to 1100rpm).

Let the engine idle then switch on the lights if the engine idle drops screw the mixture screws inwards a fraction, continue switching the lights on and off & adjusting the mix screws untill the idle doesn't alter.

Stop the motor and restart and heypresto it fires up first or second kick.

Regards Jim

P.S I guess you are using the choke correctly

Link to comment
Share on other sites

Good info and when I sit down with my mech ( I go to church with my mechanic, pretty cool) I will pass this on. Anybody got the carb specs? The carbs have been rebuilt, I just want to make sure they are set up right; float level, etc....

I guess it is a sohc XS400 ? if so I would check all engine settings, as follows :-

Intake Valve clearence 0.1mm

Ex Valve clearence 0.15mm

Set the ignition timing statically LF on the rotor for left cyl and RF for the right cyl at those marks the points should just open but ensure you have the engine on the correct stroke i.e both valves shut on the cyl you are timming

Clean out carbs (make sure no hole/jet is done also insure the rubber bungs over the jet are ok and fit snugly)

Fit new plugs (in the U.K they were BP7ES but maybe different elsewhere, but make sure the plugs are projected tip type signified by the P after the B).

Obtain a vaccum gauge,strobe & dwell meter.

attach guages,meter & strobe

Start the motor and allow to warm up.

Set the dwell to 22.5% then check ignition timming adjust as required then recheck the dwell. This is a bit of a fiddle you need to obtain the correct ignition timming & dwell so you will have to recheck both a few times !

When this done time to go to the carbs !

Set Idle to 1100 rpm or close to

Check vaccum readings both cyls should be the same and between 20-30 Kg/Cm if not adjust with the screw located between the carbs (the idle speed may alter as you adjust the carbs, if it does reset to 1100 rpm and continue with the adjustment when have the carbs set equal (and within tolerance).

If you cannot get the engine to run with the balance equal but you can with readings of say 20 on the left and 40 on the right its time to take the head off and look at the valves & bores :huh:

But if all is ok move onto the last stage

screw the idle mixture screws inwards until the engine starts to die then screw out until the idle rpm starts to increase (after this you may end up with an idle above 1100 rpm readjust it to 1100rpm).

Let the engine idle then switch on the lights if the engine idle drops screw the mixture screws inwards a fraction, continue switching the lights on and off & adjusting the mix screws untill the idle doesn't alter.

Stop the motor and restart and heypresto it fires up first or second kick.

Regards Jim

P.S I guess you are using the choke correctly

Link to comment
Share on other sites

  • Moderator

Good info and when I sit down with my mech ( I go to church with my mechanic, pretty cool) I will pass this on. Anybody got the carb specs? The carbs have been rebuilt, I just want to make sure they are set up right; float level, etc....

down load manual here

http://www.files.pioneerx.co.uk/index.php?...torbike%20Files

Link to comment
Share on other sites

Good info and when I sit down with my mech ( I go to church with my mechanic, pretty cool) I will pass this on. Anybody got the carb specs? The carbs have been rebuilt, I just want to make sure they are set up right; float level, etc....

They should be fine .. unless some one has played with them. I did the noted procedure day in day out. The only reason someone would p about with the carbs is if the did not understand what was wrong with the service of the motor or some one else said it was a good idea. I accept that the bikes r now old and the previous things could have been done in the past but I guess everything will be cool following the service plan.

regards Jim

Link to comment
Share on other sites

They should be fine .. unless some one has played with them. I did the noted procedure day in day out. The only reason someone would p about with the carbs is if the did not understand what was wrong with the service of the motor or some one else said it was a good idea. I accept that the bikes r now old and the previous things could have been done in the past but I guess everything will be cool following the service plan.

regards Jim

Just went for a ride.... My biggest prob apparently is not enough Wheaties in the right leg. Ran like a champ, plenty of pep. Seemed to be a bit touchy on the road, though. Might be that I am used to cruisers. Also seemed to be geared VERY short, but then again my last bike was a 1985 H-D XLH1000 with a 4-speed. I'll say this: $10 for a tankful of gas don't take gettin' used to....

Link to comment
Share on other sites

Just went for a ride.... My biggest prob apparently is not enough Wheaties in the right leg. Ran like a champ, plenty of pep. Seemed to be a bit touchy on the road, though. Might be that I am used to cruisers. Also seemed to be geared VERY short, but then again my last bike was a 1985 H-D XLH1000 with a 4-speed. I'll say this: $10 for a tankful of gas don't take gettin' used to....

Hi Dave

ur on cheap fuel still !!! My FS1 costs £10 to fill from empty :angry: but it will do well over 100 miles between fill ups.

They were not the best handling bikes in the world, but do the checks and service to the chassis

Change the fork oil (the clips in the top of the forks are buggers to get out).

Tyre pressures

Replace the rear shocks with ones that work, the are ok but not firm enough for my riding style !

Does the bike feel 'hinged' in the middle ? If so there is a chance you will have to shim the swinging arm (assumig the shims are still avalible).

Regards Jim

Link to comment
Share on other sites

  • Who's Online (See full list)

    • There are no registered users currently online
  • Recently Browsing

    • No registered users viewing this page.
×
×
  • Create New...