I have a 96 zr 440 top is 75 on my unit... start with easy new belt, track tension, compression test, clutch springs my be weak. run 91- 92 gas, I ran 87 one tank and lost 10 mph...

 

my 1998 ZR440 would run in the low 90's all day long. You have a problem, check the clutch and secondary for full shift, also check your belt.

Also check your air box and exhaust for a mouse nest.

 

how is it geared?

 

I would start with the gearing first...if it pulls to 40-45 like you say I would guess (?) it was geared for sno x. I would also check your clutching too. I ran a 97 XC 440 back in the day and the ZR would pretty much walk it every time and my sled ran 80+ pretty consistantly.

 

My 98 ZR 440 consumer, 85 in 1000', stock clutching, gearing, jetting.96 trail studs.Mid 90s 2000' ice. Like they said check comp, gears, clutches,jets.I know they won't pull big weights for top speed, but they pull hard to 50-60 with them.

 

Thanks for all of your help, I had one of the cylinders replated and put in new pistons and rings. Sled has greater power and top speed. I need to count the teeth on gears to see if that is why top speed is still a little low but was wondering if anyone would know about the spring on the secondary clutch. How does the amount of preload on the spring change the speed? Also I am having a hard time finding 90+ octane fuel in my area does it matter if it has ethanol (10%) or are there additives available that boost octane that would be better?

 

Each hole on the secondary spring is about 100 rpm. the tighter to the right the higher the rpm.

 

You should really search the forum before posting this. This topic has been posted about 10 times in the last 2 yrs.....

 

You should really search the forum before posting this. This topic has been posted about 10 times in the last 2 yrs.....

Although this is good advice....

This place has been around for how long now?? 7-8 yrs? What you just posted, you could post to anyone about any subject and it would be true. If everybody used the search feature all the time there would be no interaction and this place would be boring as could be.

 

top speed zr440

Take a pencil and mark a line on your primary clutch from the center of the clutch to the outer edge, on the belt surface. Take a lap on the sled top speed, then stop and shut off the engine to see if the belt shifted out on the clutch all the way, if it did the mark will be gone, if not you need to rebuild your clutches, When the parts get worn, they bind on each other and will not allow the shift. No shift, no top end. You might need to drop your top gear 1 tooth also.

 

I am going to try the pencil line idea. Is there a maximum RPM we are shooting for?

 

8500 rpm MAX

 

97 zr 440 will do about a 100 mph. back in winter of 97 at the I500 Brad Pake was clocked at 103 coming across the lake on a 20 mile stretch on a lake during the race. Everyone was shocked that the sled would go that fast.

 

Everyone was shocked that the sled would go that fast.

Likely for good reason, because 9 out of 10 of them won't come near 100 mph.