Finally time to come back(from broken motor) - Yamaha Raptor Forum
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post #1 of 5 (permalink) Old 09-09-2019, 12:36 PM Thread Starter
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Finally time to come back(from broken motor)

Been off the forum for a while, so here’s a quick story on the bike, I put a race port +2mm , 5050 cam , pc5 ,wk 54mm tb, dmc force4 dual exhaust, cp 11:5 big bore 105.5, hotrods stroker crank, it worked really good and felt really strong, but eventually the crank snout broke off, and damaged the head and cam, and it lasted 5 years, thousands of miles, riding it hard, trail riding , drag racing, you name it. So after all those years, it wasn’t my priority anymore. This happened about a year and a half ago, and the head was a big deal braker for me, and I let it sit for a good while. So now I want to start over but I want to spend much, I just want to be able to ride it again.

So here’s my question

Since I have a stock head lying around, and the big bore cylinder and piston is good to use, Im seeing if theres a decent priced stroker crank that would work, since hotrods apparently changed their process, and their crank have a really bad reputation, I would like something else, and I think if I have a stroker crank, the piston wouldn’t work with a stock crank.

And since I have a 54mm tb, how good would it work with a hot rods stage 3 and stock head? Or would a 5050 or web4 be a much better choice even with stock head?
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post #2 of 5 (permalink) Old 09-09-2019, 08:16 PM
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Originally Posted by Raptorkiller View Post
Been off the forum for a while, so here’s a quick story on the bike, I put a race port +2mm , 5050 cam , pc5 ,wk 54mm tb, dmc force4 dual exhaust, cp 11:5 big bore 105.5, hotrods stroker crank, it worked really good and felt really strong, but eventually the crank snout broke off, and damaged the head and cam, and it lasted 5 years, thousands of miles, riding it hard, trail riding , drag racing, you name it. So after all those years, it wasn’t my priority anymore. This happened about a year and a half ago, and the head was a big deal braker for me, and I let it sit for a good while. So now I want to start over but I want to spend much, I just want to be able to ride it again.

So here’s my question

Since I have a stock head lying around, and the big bore cylinder and piston is good to use, Im seeing if theres a decent priced stroker crank that would work, since hotrods apparently changed their process, and their crank have a really bad reputation, I would like something else, and I think if I have a stroker crank, the piston wouldn’t work with a stock crank.

And since I have a 54mm tb, how good would it work with a hot rods stage 3 and stock head? Or would a 5050 or web4 be a much better choice even with stock head?
How did the head and cam get damaged and the piston is OK?

Your HR crank had a 5mm stroke with a shorter rod. This allowed the use of a stock stroke piston. The old (good) style HR crank had a bushing in the small end, new (not so good) style HR doesn't have a bushing. A name brand stroker will cost minimum of $1,000 and only the 5mm stroke may use your piston. More popular are 2, 4, and 8mm stroker using a special piston, (I have some).

Your 11.5:1 piston with the 5mm stroker gave you about 12.2:1 corrected compression. Anyway, your 105.5 piston will work with a stock crank with a loss of about 2-3HP.

Your bad motor prolly made about 75 - 80HP. Your new build with big bore piston, stage 3 and factory head and 54TB may make 65 - 70HP. The 54TB may decrease the bottom end but top end should be good. A +3TB may be a better choice to keep velocity up. A stock crank will decrease torque 4 - 5.
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'19 Can-Am X3, RS Turbo, 172 HP, 1300x15 STU #2 paddle, Tribute front, DynaTec controller, cat delete, GTP blow off valve, custom flame wrap, Bent Metal windshield, Blazer wiper, rear window, 48in LED light bar, 14in LED light bar, GTP LED side lights, S3 shock tower brace, aluminum rear pull plate, 5K Badlands winch, dual batteries, 5ft lighted whips, Rugged radio and intercom, interior lights, rock lights, chase lights, over $200 additional switches, YES, street legal with dirt tires.
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post #3 of 5 (permalink) Old 09-09-2019, 11:59 PM Thread Starter
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Originally Posted by DEZPERADO View Post
How did the head and cam get damaged and the piston is OK?

Your HR crank had a 5mm stroke with a shorter rod. This allowed the use of a stock stroke piston. The old (good) style HR crank had a bushing in the small end, new (not so good) style HR doesn't have a bushing. A name brand stroker will cost minimum of $1,000 and only the 5mm stroke may use your piston. More popular are 2, 4, and 8mm stroker using a special piston, (I have some).

Your 11.5:1 piston with the 5mm stroker gave you about 12.2:1 corrected compression. Anyway, your 105.5 piston will work with a stock crank with a loss of about 2-3HP.

Your bad motor prolly made about 75 - 80HP. Your new build with big bore piston, stage 3 and factory head and 54TB may make 65 - 70HP. The 54TB may decrease the bottom end but top end should be good. A +3TB may be a better choice to keep velocity up. A stock crank will decrease torque 4 - 5.
This is exactly what I needed to find out, appreciate your opinion, help and suggestions .

I need to clean the piston up and do a better inspection on it, it has marks on it but not sure if that would compromise its functionality?

Can I get any hotrods old good style crank anywhere yet?

And how much are the ones you have with piston?
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post #4 of 5 (permalink) Old 09-10-2019, 12:41 AM
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If the piston has any damage it's strength may be compromised. If reused be sure to replace and gap the rings.

I'm sure there are older HR cranks out there, but hard to find for sale. I've had 2, one sold in my last 727 and the other to a builder.

I don't have any stroker cranks, just stock. I do have 2, CP 105.5 pistons for 2mm and 4mm cranks.

'19 Can-Am X3, RS Turbo, 172 HP, 1300x15 STU #2 paddle, Tribute front, DynaTec controller, cat delete, GTP blow off valve, custom flame wrap, Bent Metal windshield, Blazer wiper, rear window, 48in LED light bar, 14in LED light bar, GTP LED side lights, S3 shock tower brace, aluminum rear pull plate, 5K Badlands winch, dual batteries, 5ft lighted whips, Rugged radio and intercom, interior lights, rock lights, chase lights, over $200 additional switches, YES, street legal with dirt tires.
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post #5 of 5 (permalink) Old 09-11-2019, 04:14 PM Thread Starter
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Originally Posted by DEZPERADO View Post
If the piston has any damage it's strength may be compromised. If reused be sure to replace and gap the rings.

I'm sure there are older HR cranks out there, but hard to find for sale. I've had 2, one sold in my last 727 and the other to a builder.

I don't have any stroker cranks, just stock. I do have 2, CP 105.5 pistons for 2mm and 4mm cranks.
I have a stock crank, I think Ill throw it together like that and save up for a stroker, big bore high compression race ported head with a web4 or 5050 cam
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