Dying due to air promblem or overheating maybe?

[Viirin]

I been having some issues with my GZ as of late - if i have a clear run for about 90 seconds at about 35-40 mph, the bike looses power and then the engine cuts out all together. The bike can't be started immediately but it can be after about 40 seconds but then the idle sounds very uneven and if it's ridden again, dies in about 100 meters. sometimes if i've got a fairly long run up to a set of lights i can hear the engine idling at about half of what it normally does and then it feels like a race to for the lights to turn so i can get going before it cuts out. - I thought the bike wasn't getting enough fuel but i checked the line and it seems fine. Maybe it isn't getting enough air or is overheating or both. I guess it could always be the carb again but the overheating idea just came to me because i had such a nightmare with it last summer and it always seems to break down on the sunny days :cry: Any similar experiences you guy could share would be greatly appreciated as it might save me pushing it 4 miles down the motorway/free-way to the next exit in full gear! thanks.



just before i forget so far i've :
checked/cleaned the fuel line - seems clear
checked the oil level - seems fine
added some fuel additive just in case

thanks again
Vii

[JWR]

Does it do this with the fuel lever in the PRI position??

[BillInGA]

Does it do this with the fuel lever in the PRI position??

That's a great question. My initial thought was fuel starvation, although you said you checked the flow from the tank.

You may have a vacuum leak between the carb and the fuel valve, causing the fuel valve to shut off fuel when it's set to ON or RES.

[blaine]

Let the carb cleaner work for a while to see if there is any difference in the way it runs then you will know if you have a carb problem or not.It sounds like your carb is plugged and when you let bike sit carb fills up again.

[Viirin]

I'll stick it on Prime tomorrow and see if it's a vacuum problem but there seemed to be decent suction from it last time I had the tank off which wasn't too long ago - is it common enough for them to get blocked or loose suction?

How often should you clean or replace the air filter? Could a dirty one stop the air from cooling the bike or even starve the combustion chamber?

[JWR]

I don't think the filter is your problem.

Will the bike rev up in neutral when you first start it up??

[blaine]

Not common to lose vacuum unless diaphain is gone in petcock.Fuel would still flow if in prime possision.Filter should be changed if dirty on the INSIDE or oil soaked.If engine running very lean will cause it to overheat.Plugged filter will cause engine to run very rich and flood.

[Viirin]

Yeah she'll rev fine in neutral, it only dies after a long stretch of consistently high revs but after that it has trouble even in neutral...at least for about 30 minuets. It's so strange, it's like it has more trouble idling after it gets warm which is completely counter-intuitive to what i normally think. I had it running today for about 10 minuets in neutral and it didn't seem to have an problems ticking over at the normal pace (but i never thought of setting it to PRI).

Thanks again for getting back to me so quickly - I got exams coming up in the next couple of weeks and i'd be sunk if i couldn't get the bike running - you guys are life savers!

[Viirin]

oh no - just checked the fuel line and it's keeps flowing even when it's in the PRI position - what kind of implications does this have? not good i'm guessing...

[BillInGA]

The fuel is supposed to keep flowing when the fuel valve is in the PRI (prime) position. The question is whether the engine continues to act up when you ride with the fuel valve in PRI.

[blaine]

The fuel should NOT flow anywere but PRIME If it does the diaphram is gone in the petcock.

[Canuck]

are the valves up to spec?

[JWR]

You must ride the bike while in the PRI position in order to tell if it is a vacuum leak.

[Water Warrior 2]

Also check the airbox drain tube. It hangs down under the frame a bit and has a plug in the end. Remove plug, drain any crap out and put the plug back in. Did you say you had the tank off recently ? Hey guys, is there an overflow tube or vent tube that might have gotten squashed upon tank install ? I can't honestly remember since it has been 3 years from the last GZ tank R/R.

[blaine]

Only overflow tube is on float bowl of carb.

[Viirin]

I'll try taking her for a ride today with it in PRI - if it's running fine should it continue to run or will it run out of juice while primed?

when you say the "plug" at the end of the airbox drain tube, I couldn't find a plug - it just looks like a loose pipe hanging down - am I missing something here?

[alantf]

when you say the "plug" at the end of the airbox drain tube, I couldn't find a plug - it just looks like a loose pipe hanging down - am I missing something here?

First of all, check which drain tube you're talking about - there are 2 - The tube that comes from the bottom of the carb does NOT have a plug. The tube that comes from the bottom of the air filter box DOES have a plug (fixed with a clip around the bottom of the tube) If the plug is definitely missing from the bottom of the air box tube, I've heard that a golf tee will do the job until you can get the proper one from the dealer. :2tup:

[Viirin]

Oh right i thought the one at the bottom was missing a plug but if there wasn't supposed to be one in the first place then thats one less thing to wory about. I'll try running it in PRI tonight if i get a chance later on. The bike seems to be ticking over alright so i don't think it's anything TOO major.

In terms of the diaphram going - could a fuel additive be the cause of it? I mean can the disintegrate the rubber seals around them if the mixture was too concentrated?

[blaine]

A posibality.but not likley as there are no rubber parts used any more.

[Viirin]

Right, the plan is to fix her on Saturday, i've ordered a few things and the should arrive Friday night.
- I coouldn't find an air filter online that wasn't really, really expensive so i just got a can of compressed air to blow the crap out of my current one. Could this damage it?
- I got a new oil filter (figure it couldn't hurt and seeing as i'm taking the bike apart anyway...) from K&N, Are these alright?
- Lastly, if the diaphram is really messed up, is it possible to buy replacement parts or would i have to buy an entire petcock?

Thanks again for all the help and rapid replies

Vii

[blaine]

If cleaning filter with air blow from "OUTSIDE" only or filter will be ruined.Look up 'HIFLO-FILTRO-HFA-3503" air filter about 15.00 dollars.oil filter is"HF-136'.from same site.Don't know if you can buy parts for petcock.check with dealer.

[Viirin]

ok good news - I cleaned out the air filter and carb yesterday - i didn't see anything major coming out of the air filter but when i drained the bottom of the air box you should have seen the amount of crap that came out - I don't think it had been done since I bought it and now all the backfire is gone! - I'm about to take it on a longer run now to see if she still dies at about 40mph but i'm feeling more confident that it won't since it's have a litre of oily-watery-gunk lighter than it was the last time.

Thanks a million for all the help as usual guys
I'll let you know if she's back to normal later on tonight

Thanks again
Vii

[Viirin]

Took it out for a longer run and the loosing power issue seems to have gone - i replaced the fuel line just in case it was contributing to the problem - finally shes back on the road!

[Water Warrior 2]

Sometimes it is the simplest bit of maintenance to get the bike going properly. Glad it worked out and wasn't more complicated.

[blaine]

Great,ride safe!