FZR questions

[trailer rails]

Newbie warning: Long time reader, first time poster.

I recently bought a 94 FZR600R. It is my first street bike. I been riding dirt bikes for many years but never made the transiton to the street untill late this summer. I have been riding the crap out of this bike. The bike is a little beat up. It is missing it's side plastics. I put some new rubber on it, treated it to a K&N air filter, fresh oil, and some R1 front brakes and lever.

The problem I have been having is with the water temp. Recently it has been very slow to warm up, if at all. I rode it today and the needle barely moved off the peg. It was about 25-30 deg F out today. Could have the previous owner removed the t-stat completly for some reason? When I get stuck in traffinc in warmer temps the bike likes to creep up tword the top of the tem guage. Is this normal? Should I do the old school truck trick and put some cardboard in the rad? Also I am not shure my fan is working, I have never heard it running. Is this another problem I should look into?

Do I need to worry about rejetting in these colder temps? This is my first four stroke bike. I have been told that they can handle a broader range of temps and altitudes than two strokes. It revs up quick and the RPMs drop quickly back to the idle just liek it is supposed to. That is how I usally check my two storkes. If the revs stayed high for a sec and then dropped it was lean, if they dropped below idle and then returned to idle then it was rich.

Thanks, and I love this site. I visit almost daily.

[Hooligan]

welcome to the site trailer!

there have been some threads in some of the model specific forums regarding operating temps. try a search and see what turns up. i know there has been some discussion in the past regarding thermostats and such in the yzf750 section.

i can tell you that m yzf750 ran a bit cool as long as it was moving. stop in traffic though, and the temp gauge starts climbing pretty steadily.

you can test your fan and thermostat, i just can't recall how to do it. someone will enlighten both of us.

i wouldn't worry about jetting changes. although four strokes can be jetted differently to adjust your fuel delivery, they are nowhere near as finicky to jetting changes as two-strokes. on my bonnie, i made some slight changes to my intake and exhaust which required some jetting changes. a bit more air in and a bit more air out required more fuel everywhere.

flat-slides on the other hand, can be a bit of a pain. so i am told.

[ftang]

Your temp guage behaviour sounds like just what I'd expect from my 750. It's practically an inverse indicator of tyre temperature: the faster you go, the cooler it gets. (I notice some track-only bikes have had the fans removed.) Then you slow down and up it goes, right to almost 100C. And 25-30 deg F is below freezing, isn't it? So there's sub-zero air rushing past the rad. I would hardly expect it to lift until you were in traffic.

My fans cuts in at nearly 100C. Maybe yours has just never got that hot? If it's not working, I guess you'll eventually boil over, so if you don't, maybe it's ok. Obscuring the rad would stop the fan sucking air through when it needs to. And you shouldn't need to re-jet for winter. Big altitude changes, maybe? A bike I once bought in LA ran like a dog over the Rockies.

Only thing is, if it stays properly cold, and you only do short trips, you could put in a thinner oil which'll get up to working temp a bit quicker.

[djalbin]

Trailer Rails,
Normal thermostat opening temperature is 80 to 84 degC (176 to 183 degF). Fully open at 95 degC (203 degF). Valve travel when fully open is not less than 8mm (5/16 of an inch).
The only way to check the thermostat is to take it out and put it into a pan of water. Using a thermometer, gradually heat the pan of water and check the temperature when the value first starts to open. Should be 80 to 84 degC. Continue heating the water until the valve is fully open. Should be 95 degC. When the valve is fully open, measure how far the valve has traveled. Should be 8mm or more.
Of course, if you're going to bother taking the old one out for testing you could just skip the test and replace it with a new one (they're not that expensive).
As far as your bike's behavior, it sounds like mine ('94 FZR1000). The bike will heat up when sitting still and cool down when moving. During the summer it heats up quickly, high temperature is 100 degC, holds at 100 degC when the fan starts up, and depending on ambient temperature and altitude during my ride - will be anywhere from 60 to 80 degC while moving. During the winter, it heats up slowly, high temperature around 80 degC when sitting still, and depending on ambient temperature and altitude during my ride - will be anywhere from 40 to 60 degC while moving.
The cooling capacity on these bikes is not large and air flow while moving makes a big difference. The coolant capacity, depending on year and model, range from 2.2 qts to 3.0 qts.
Don

[trailer rails]

Wow! You guys shure know your shit.
It looks like I don't have much to worry about. I may switch to a lighter oil, as suggested, because I do a lot of short trips.
I have never smelled it or heared it boiling over so I guess I am ok on the high end. I don't ride too much in the colder weather anyway.
They salt the roads around here in the winter so I wont ride unless it rains(to wash the salt off the roads) and then the weather turns nicer.

[willi]

you must have a lot of rusty bombs over there if they salt the roads.

[trailer rails]

LOL, yea it sucks. I moved here from a place the does not use salt. My 10 year old truck did not have one spot of rust on it, even on the bare steel frame. Within 2 years I have rust poping up everywhere. The massive amounts of humidity does not help matters either.