Problems with Honda RPM's

Michael Robertson · Joined: 10 Apr 2002 Posts: 24

I'm having trouble getting over 3000 RPM's on my 6.5hp Honda. Anyone have any idea what I might try? This is a sealed engine class, so I can't change jets or anything. Can't even change the exhaust pipe. And I run out of steam at the end of the straight.

Chad Stapleton · Joined: 19 Jul 2001 Posts: 4403

Assume you have disconnected the governor , and the throttle is opening fully?
Check the choke is opening & closing correctly,
fit new valve springs (Gx140 if allowed)
& reset lash
Clean out the carb
Check correct jets fitted
New plug
Compression test if still no good.

Michael Robertson · Joined: 10 Apr 2002 Posts: 24

Thanks Chad. You don't know any links for people running the GX200 6.5hp Hondas do you?
I can't find anything anywhere on the net.

Chad Stapleton · Joined: 19 Jul 2001 Posts: 4403

the OHC / Honda forum on 4cycle.com has a fair traffic, but most honda racing is in Europe or Canada
Try Canada's JWO racing :- http://members.rogers.com/jworacing/
Or www.karting.co.uk - tech tips section has a series of articals for the GX160 but is applicable to the 200
The Author , Brian Pollard, has produced a GX tuning and maintenance "bible" available on CD Rom

Mike Robertson · Posted: Thu May 30, 2002 7:29 pm Post subject: Problems with Honda RPM's

Thanks Chad, that is a great help.

adam daly · Joined: 01 Jun 2002 Posts: 3 Location: IRL

it could be valve bounce. this probably can be easily fixed with new springs. also check that the valves seat well and that there is no leakage. check this by pouring fuel into the exhaust/inlet port when valves are in place and check to see where any fuel leaks through.

adam

Hance Lord · Joined: 30 Oct 2001 Posts: 44 Location: Afghanistan,

quote:
Originally posted by Michael Robertson:
I'm having trouble getting over 3000 RPM's on my 6.5hp Honda. Anyone have any idea what I might try? This is a sealed engine class, so I can't change jets or anything. Can't even change the exhaust pipe. And I run out of steam at the end of the straight.

If you are running a sealed engine I'd say you're out of luck.
Carb adjustments and Governer settings should help, but if these engines are all set to be the same you may just need a gearing change.

Chad Stapleton · Joined: 19 Jul 2001 Posts: 4403

Even bone stock, with the governor, the GX200 makes peak power at 3600rpm , so of you cant make that -there is something out of whack ! even lazy valve springs wont slow you that much.
"Sealed" stock racing motors should run to 5500 - 5900 rpm.
Is the governor fitted or not ??
Oh, and have you checked your rev counter ? some are set for 2-strokes and read half engine speed if used on a 4-stroke !!!

Hance Lord · Joined: 30 Oct 2001 Posts: 44 Location: Afghanistan,

Ummmm...
A GX200 k1 Honda has a flywheel with one ignition exciting magnet attached. It is a four stroke cycle engine. Wouldn't it fire off a spark every time the magnet passes the coil regardless of what the valves are doing?
So a Honda GX200 rev counter should be set to "2 stroke", right?

Graham Macleod · Posted: Wed Jun 05, 2002 3:40 am Post subject: Problems with Honda RPM's

right

Rodney Ebersole · Posted: Wed Jun 05, 2002 4:32 am Post subject: Problems with Honda RPM's

Right, but there is a setting on most digatrons that make it show 1/2 the rpm's that it is really doing. If your really only turning a little over 3 grand the thing propably wouldn't pull its self out of the pits.

Dean Giles · Joined: 04 May 2002 Posts: 4 Location: Saskatoon

I run a 6.5 hp honda. My clutch doesn't engage until 2600-2800 RPM. I agree that you would barely move at 3600. I am finding that 6400 RPM is about max power although I have pulled 6700 RPM on some days and geared for a short track.

Hance Lord · Joined: 30 Oct 2001 Posts: 44 Location: Afghanistan,

Have any of you ever driven a rental kart? Around here they are stock 5.5 and 6.5 Honda engined. These Bone Stock engined karts pull themselves out of the pits, they are 450 pounds and governer is not even touched. The 5.5 *max out* at 3800 rpm.

Micheal did you get it figured out? Fill us in, we all want to learn.

Jim Testioro · Joined: 18 Dec 2001 Posts: 19 Location: Northern Calif.

Good point I guess it depends on gearing and stuff.

adam daly · Joined: 01 Jun 2002 Posts: 3 Location: IRL

i had a similar problem last weekend. turned out to be fuel, but i think that is only really a problem in northern ireland. we have people over here diluting the petorl with parrafin and diesel to earn a larger profit.
but it is worth considering. look at the fuel and if it is slightly greenish, its been doctored. only use petrol that is very yellow.

adam http://www.spadboys.org.uk/adamdaly