90,91 & 97 engine compatability

bunk · Post by **bunk** » Fri Aug 06, 2021 3:22 pm

I have a raft of fzr1k projects and know that i am going to run into some damaged engines during their recommissioning. I know the 90 has its own oil cooler versus the 91 with a heat exchanger. I figure the ace has the same system. What i am curious about is parts swapping between the 3. Also wondering if the ace engine will bolt into the older fzr frame, and can the fzr carbs bolt to the ace engine? The ace engine has 1003 miles and is pretty much a parts bike.

bunk · Post by **bunk** » Fri Aug 06, 2021 5:46 pm

Thank you ! Heres another question, is there a typical failure point on the exup engines? I see alot of cranks on ebay with damage, and my engine has a knock.

bunk · Post by **bunk** » Fri Aug 06, 2021 6:15 pm

In the last 2 years that ive been amassing fzr1k bits every bike ive run into had a knock. Between 8 and 14k miles is the average. fwiw this is the most active board in the world that ive found, fzr's are and their forums are dead in he states

Im just trying to relive some youth as a 89 was the first literbike i rode. Now i have 4 of them in different states of repair, i just want to get the 90 and 91 going, hopefully i have enough parts.

yzfpaul · Post by **yzfpaul** » Sat Aug 07, 2021 3:13 pm

Hi ya
If I had to choose an engine I'd pick the thunderace it has a lighter crank and better midrange clout
What you could do is use the earlier fzr barrels which will give you the exact mounting holes for the frame

Best of luck with the build
And yes this is the ultimate exup forum

bunk · Post by **bunk** » Sat Aug 07, 2021 3:24 pm

yzfpaul wrote:Hi ya
If I had to choose an engine I'd pick the thunderace it has a lighter crank and better midrange clout
What you could do is use the earlier fzr barrels which will give you the exact mounting holes for the frame

Best of luck with the build
And yes this is the ultimate exup forum

Im glad i found this place as im pretty invested in all these bits. I am a machinist with machines at home, so making bits and pieces is easily done. I am a fan of keeping factory assembled engines together, so if the 90's engine is too hurt i'll make the ace engine work. Im going to pick up another parts bike next week, a 91 with a knock

bunk · Post by **bunk** » Thu Aug 12, 2021 2:50 pm

How similar/swapable are the exhaust headers between 90, 91 and 97?

Post by **Stig** » Thu Aug 12, 2021 4:39 pm

90 & 91 direct fit. Depending on application the rad has to be spaced out to fit the Exup headers in the ace frame

bunk · Post by **bunk** » Thu Aug 12, 2021 6:07 pm

Stig wrote:90 & 91 direct fit. Depending on application the rad has to be spaced out to fit the Exup headers in the ace frame

That seals the deal, going to sacrifice the 91 to get the 90 going. Its blue/white gray if anyone needs body panels send me a message, i am in Seattle.