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535 Cylinder problems


peddro

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Hi, has anyone had this problem with a 535 cheetah cylinder?

 

5 of the 11 studs are pulling out of the cylinder, however the threads have not been stripped it just seems to be pulling all the metal around the stud from out of the cylinder.

The engine has been run for over 100 miles with no problems, then I removed the head to check the Orings & tried to re-torque the head & it felt like some of the threads where going to strip, but in fact the threads are sound its just pulling the stud & thread together out of the cylinder!

All were fine when I first built the motor & all torqued down correctly to 20lb, I have now got a mess!

 

I have been told that it maybe a heat treatment issue when the cylinder was made?

 

Also I was told that the reason for this was that “I over tightened the studs” (So how come the threads didn’t strip then?).

Has anyone seen this before?3b64beb8.jpg

 

35bab4f0.jpg

 

Many thanks

 

Peddro.

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Hey Peddro,

Nice clear pics. I have been running my Cheetah 4 mil cylinder for a few years and have not seen this issue.

I would call Calvin Pollet at CP industries, the maker of the cylinder, and get his input. You could also send him an email.

 

You may also want to post this on atvdragracers.com to get their input.

 

As a side note, why are the water passages so rusty? Are you running water straight from the garden hose in your bike?

 

Mailman

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Hey Peddro,

Nice clear pics. I have been running my Cheetah 4 mil cylinder for a few years and have not seen this issue.

I would call Calvin Pollet at CP industries, the maker of the cylinder, and get his input. You could also send him an email.

 

You may also want to post this on atvdragracers.com to get their input.

 

As a side note, why are the water passages so rusty? Are you running water straight from the garden hose in your bike?

 

Mailman

 

Thanks for the advice, I will try to contact Calvin.

 

Yes, just using straight water just to start with, as I was setting the bike up & was going to be draining the coolant a few times, so didnt want to waste the antifreeze.

I will add antifreeze mix, now that I have sorted out the ignition & jetting. Just need these studs sorting out now!

The bike was going great before noticing this stud issue, never mind I am sure someone will help.

 

Best regards

 

Peddro.

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Could this possably be a sign of a trinity dome? To much compression? Pm windycityjohn and he'll give u a piece of mind. The only way I see that happening is over torqueing the head stud, I no its tuff to admit to but its a life lesson we all make once. You can repair them by using a heli coil, good luck

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Could this possably be a sign of a trinity dome? To much compression? Pm windycityjohn and he'll give u a piece of mind. The only way I see that happening is over torqueing the head stud, I no its tuff to admit to but its a life lesson we all make once. You can repair them by using a heli coil, good luck

Hi Nick,

 

Hi Nick thanks for the reply.

However, but I am a "City & Guilds" of London Engineer.

So these were all torqued down correctly to 20lb.

 

I have been told that I can get them repaired with either a Helicoil, or a Time-Sert,

but I am concerned with the lack of metal by the "O"ring groove.

 

However these are Trinity domes, 27cc, is their a problem with them?

Engine spec:-

They are Trinity Racing Domes 73.5-27-10 (27cc)

Squish:- 1.01mm.

Ignition is RD/YPVS F2 std CDI Unit

Pipes are custom built.

Bellies:- 129mmm OD.

Stingers:- 26mm ID.

Stinger Length approximately:- 220mm

Mikuni TM38mm carbs

K&N 4" air filters.

Set up:- 30:1 oil/fuel ratio. Super Unleaded

sorry but it has to be pump gas, 97Ron in the UK) As its a road bike.

Oil Silkolene Pro 2

Spark plugs: NGK BR10EV

 

I have built lots of race engines & have won 2 British 250cc Championships & twice runner-up,

plus countless other titles, so I can build the odd engine.

(sorry Nick, but I hope I dont seem to be disrespectful).

 

 

This is a great shame as the bike is going great & other that the pipes,

everything else was made by hand by myself, including all the carbon fiber.

 

 

post-67-127153333541.jpg

 

 

Thanks again.

 

Peddro.

Edited by peddro
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Hey Peddro,

The angle cut on the Trinity domes is not always accurate which can cause a convergent squish angle and wreak havoc on the msv and combustion process. It caused me to go through a lot of money, time, and dyno testing to find the root cause.

On another note, do you have the DM shell or the older style Cheetah shell? I feel there are some issues here as well. PM me for the details.

 

Mailman

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Hey Peddro,

The angle cut on the Trinity domes is not always accurate which can cause a convergent squish angle and wreak havoc on the msv and combustion process. It caused me to go through a lot of money, time, and dyno testing to find the root cause.

On another note, do you have the DM shell or the older style Cheetah shell? I feel there are some issues here as well. PM me for the details.

 

Mailman

 

Mailman,

You have got an Email.

 

Peddro

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Mailman has got this. He's in good hands. :notworthy:

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Nick, Now you just have to get that Trinity sticker off your machine and update your picture so we will know your bike is fast now. LMAO. :rotflmao:

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  • 6 years later...

I wish I knew where all the cheetah cylinders went. Can you imagine what a hit they would have been in today's market with how well the servals are doing. That is if they got the bugs with the power valves and domes worked out.

I had 2 16 mil Cheetahs (at least 1 was PV) and, a 14 Mil. 2 of them were sold in MO, I forget where the other went. The 14 Mil was a Dan Hull motor and was the most impressive. None of them compare to what Super Cubs are doing now though. I think I dynoed one of the 16s with the power valves installed normally and with them locked all the way up and not a lot of difference if I recall. To me, that says something was set up wrong (as you imply with your statement about getting the bugs worked out.)
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