Trying to find rpm

sticky · 10 July 2006, 18:31

Fairly new to ribbing but find this site extremely helpfull, fingers crossed someone can help with this one.
Since using my rib I,ve noticed that my honda 90 never gets above 5000k at full throttle(Honda state 5k-6k).I thought I would look under the bonnet and investigate.Noticed that the throttle linkage was only at the 3/4 position/usage also the carbs were not fully open.So I thought it was a simple task of adjusting the throttle cable.
Next trip out WOW 5800k rpm and a lot faster great I thought!
Not so, as I went into neutral the idle speed was 1200rpm and subsequently could not get it into gear.Back under the bonnet back to original everthing ok.
What am doing wrong?
Why cant I find that extra rpm?

Andy Moore · 10 July 2006, 18:35

I am no expert, but what about a different prop?

slimtim · 10 July 2006, 18:54

if its anything like my tohatsu...

There will be an idle adjustment screw located by the carbs which adjusts the rpm at idle. It should be about 900 ish out of gear and 800 ish in gear i think. It sounds like you need to adjust the throttle cables as you did but then adjust the idle screw to calm her down.

Failing that, props wrong

Ribald · 10 July 2006, 19:23

Quote:

Originally Posted by Andy Moore

I am no expert, but what about a different prop?

Sound about right. When we changed the props over on our Suzuki the rpm went up by over 600rpm.

Nos4r2 · 10 July 2006, 22:41

If the throttle isn't opening fully then that's where the problem lies- WOT means the butterflies at fully open position. I doubt it's a prop problem.

How does the linkake work between the cable end and the throttle butterflies? Could it be a slightly bent linkage bar or similar? I'm not familiar with the setup under the cowl on Hondas.

fast fred · 11 July 2006, 11:59

you needed to adjust the carb linkage, not the cable, put the cable back.
should be a cam that drives the carbs, depending on what flavor moda ya got.

RAS · 11 July 2006, 13:23

Sorry to disagree but my first check would be to see the amount of movement on the throttle cable, it sounds as though you are not moving the linkage far enough, ie adjust for full throttle and the cable then does not retract far enough for tick-over.

If you check inside the gear/throttle lever on the console you should see several different positions for attaching the throttle cable, each giving a different amount of cable movement between tickover and full throttle. Just chose the one that suits the amount of movement that the engine needs.

Hope that this helps.